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RFC 2301

 
 
 

File Format for Internet Fax

Part 3 of 3, p. 49 to 77
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7. Lossless Color Mode

   This section defines the lossless color mode or Profile L of TIFF for
   facsimile. Implementations of this profile are required to also
   implement Profiles S and C.

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7.1. Overview

   This mode, defined in [T.43], uses JBIG to losslessly code three
   types of color and grayscale images: one bit per color CMY, CMYK and
   RGB images; a palettized (i.e. mapped) color image; and continuous
   tone color and grayscale images. The last two are multi-level and use
   the L*a*b* encoding specified in [T.42].

7.1.1. Color Encoding

   While under development, this mode was called T.Palette, as one of
   its major additions was palette or mapped color images. Baseline TIFF
   only allows RGB color maps, but ITU-T Rec. T.43 requires L*a*b* color
   maps, using the encoding specified in ITU-T Rec. T.42. Palette color
   images are expressed with indices (bits per sample) of 12 bits or
   less, or optionally 13 to 16 bits, per [T.43].

   Enabling T.43 color maps in TIFF requires the extension field
   Indexed, defined in [TTN1], and the PhotometricInterpretation field
   value 10, defined in Section 6.2.1. The following table shows the
   corresponding PhotometricInterpretation, SamplesPerPixel,
   BitsPerSample and Indexed field values for the different T.43 image
   types.

       +----------------------------------------------------------+
       | Image Type |PhotometricIn| Samples  | Bits Per | Indexed |
       |            |-terpretation| PerPixel |  Sample  |         |
       |------------+-------------+----------+----------+---------|
       |     RGB    |    2=RGB    |     3    |    1     |    0    |
       +----------------------------------------------------------+
       |     CMY    |    5=CMYK   |     3    |    1     |    0    |
       +------------+-------------+----------+----------+---------+
       |     CMYK   |    5=CMYK   |     4    |    1     |    0    |
       +------------+-------------+----------+----------+---------+
       |   Palette  |  10=ITULAB  |     1    |    n     |    1    |
       +------------+-------------+----------+----------+---------+
       |  Grayscale |  10=ITULAB  |     1    |   8, 12  |    0    |
       +------------+-------------+----------+----------+---------+
       |    Color   |  10=ITULAB  |     3    |   8, 12  |    0    |
       +------------+-------------+----------+----------+---------+

7.1.2. JBIG Encoding

   T.43 uses the single-progression sequential mode of JBIG, defined in
   ITU-T Rec. T.82. To code multi-level images using JBIG, which is a
   bi-level compression method, an image is resolved into a set of bit-
   planes, and each bit-plane is then JBIG compressed. For continuous
   tone color and grayscale images, Gray code conversion is used. The

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   Gray code conversion is part of the data stream encoding, and is
   therefore invisible to TIFF.

7.2. Required TIFF Fields

   This section lists the required fields, in addition to those in
   Section 2.2.1, and the values they must have to be compatible with
   ITU-T Rec. T.43.

7.2.1. Baseline Fields

ImageWidth(256).                                           SHORT or LONG
    Same page widths as the base color mode; see Section 6.2.1.

NewSubFileType(254) = (Bit 1=1).                                    LONG
    RequiredByTIFFforFAX
    Bit 1 is 1 if the image is a single page of a multi-page document.
    Default = 0 (no subfile bits on, so may not be omitted for fax)

BitsPerSample(258) = 1, 2-8, 9-16.                                 SHORT
    Count = SamplesPerPixel
    RGB, CMY, CMYK: 1 bit per sample
    Continuous tone (L*a*b*): 2-8 bits per sample, 9-12 bits optional
    Palette color: 12 or fewer bits per sample, 13-16 bits optional
    Note: More than 8 bits per sample is not baseline TIFF.

ColorMap(320).                                                     SHORT
    Count = 3 * number of sample values
    Lossless color fax mode supports palette-color (indexed) images
    where the single component value is used as an index into a full
    color lookup table stored in the ColorMap field. The sample value is
    encoded using the number of bits given by the BitsPerSample field
    value. However, per [T.43],the number of sample values may be less
    than 2**BitsPerSample. The color lookup table is only required to
    have as many entries as there are number of sample values. For
    palette-color images in lossless color fax mode, the ITULAB encoding
    with 8 or optionally 12 bits per color map value is supported. To
    utilize a color map, the TIFF Indexed field must be present. TIFF
    orders the color map values so that all the L* values come first,
    followed by all the a* values and then all the b* values. Because
    ITU-T Rec. T.43 specifies a "chunky" ordering with the L*a*b*
    components of the first value, followed by those of the second
    value, and so on, reproducing color map values from a fax data
    stream in a TIFF file requires reordering values.

Compression(259) = 10.                                             SHORT
10: ITU-T Rec. T.43 representation, using ITU-T Rec. T.82 (JBIG)
    coding

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FillOrder(266) = 1 , 2.                                            SHORT
    RequiredByTIFFBaseline
    Profile F readers must be able to read data in both bit orders,
    but the vast majority of facsimile products store data LSB
    first, exactly as it appears on the telephone line.
              1 = Most Significant Bit first.
              2 = Least Significant Bit first

PhotometricInterpretation(262) = 2, 5, 10.                         SHORT
    2: RGB
    5: CMYK, including CMY
    10: ITULAB
    Image data may also be stored as palette color images, where pixel
    values are represented by a single component that is an index into a
    color map using the ITULAB encoding. This color map is specified by
    the ColorMap field. To use palette color images, set the
    PhotometricInterpretation to 10,SamplesPerPixel to 1, and Indexed to
    1. The color map is stored in the ColorMap field. See Section 7.1.1
    for further discussion on the color encoding.

ResolutionUnit(296) = 2, 3.                                        SHORT
    The unit of measure for resolution. 2 = inch, 3 = centimeter;
    Default = 2 (field may be omitted if this is the value)

SamplesPerPixel(277) = 1, 3, 4.                                    SHORT
    1: Palette color image, or L*-only if Indexed = 0 and
       PhotometricInterpretation is 10 (ITULAB).
    3: RGB, or L*a*b*, or CMY if PhotometricInterpretation is 5 (CMYK).
    4: CMYK.

XResolution(282) = 100, 200, 300, 400.                          RATIONAL
YResolution(283) = 100, 200, 300, 400.                          RATIONAL
    The resolution of the image is expressed in pixels per resolution
    unit. In pixels per inch, allowed XResolution values are: 100, 200,
    300, and 400. The lossless color fax mode requires the pixels to be
    square, hence YResolution must equal XResolution. Base resolution is
    200 pixels per inch. See Section 2.2.2 for inch-metric equivalency.

7.2.2. Extension Fields

Indexed(364) = 0, 1.                                               SHORT
    0: not a palette-color image
    1: palette-color image
    This field is used to indicate that each sample value is an index
    into an array of color values specified in the ColorMap field.
    Lossless color fax mode supports palette-color images with the
    ITULAB encoding. The SamplesPerPixel value must be 1.

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7.2.3. New Fields

Decode(433)                                                    SRATIONAL
    Decode is used in connection with the ITULAB encoding of image data
    and color map values; see Section 6.2.3.

7.3. Recommended TIFF Fields

   See Sections 2.2.3. and 2.2.4.

7.4. Lossless Color Fax Mode Summary

   Recommended fields are shown with an asterisk *.

        +--------------------+--------------------------------------+
        |   Baseline Fields  |             Values                   |
        +--------------------+--------------------------------------+
        | BitsPerSample      | 1: Binary RGB, CMY(K)                |
        |                    | 8: 8 bits per color sample           |
        |                    | 9-16: optional                       |
        +--------------------+--------------------------------------+
        | ColorMap           | n: LAB color map                     |
        +--------------------+--------------------------------------+
        | Compression        | 10: JBIG, per T.43                   |
        +--------------------+--------------------------------------+
        | DateTime*          | {ASCII}:  date/time in the 24-hour   |
        |                    | format "YYYY:MM:DD HH:MM:SS"         |
        +--------------------+--------------------------------------+
        | FillOrder**        | 1: Most significant bit first        |
        |                    | 2: Least significant bit first       |
        +--------------------+--------------------------------------+
        | ImageDescription*  | {ASCII}: A string describing the     |
        |                    | contents of the image.               |
        +--------------------+--------------------------------------+
        | ImageWidth         | 864, 1024, 1216, 1728**, 2048, 2432, |
        |                    | 2592, 3072, 3456, 3648, 4096, 4864   |
        +--------------------+--------------------------------------+
        | ImageLength**      | n: total number of scanlines in image|
        +--------------------+--------------------------------------+
        | NewSubFileType     | 2: Bit 1 identifies single page of a |
        |                    | multi-page document                  |
        +--------------------+--------------------------------------+
        | Orientation        | 1**-8, Default 1                     |
        +--------------------+--------------------------------------+
        | PhotometricInter-  | 2: RGB                               |
        | pretation          | 5: CMYK                              |
        |                    | 10: ITULAB                           |
        +--------------------+--------------------------------------+

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        +--------------------+--------------------------------------+
        | ResolutionUnit     | 2: inch                              |
        |                    | 3: centimeter                        |
        +--------------------+--------------------------------------+
        | RowsPerStrip       | n: number of scanlines per TIFF strip|
        +--------------------+--------------------------------------+
        | SamplesPerPixel    | 1: L* (lightness)                    |
        |                    | 3: LAB, RGB, CMY                     |
        |                    | 4: CMYK                              |
        +--------------------+--------------------------------------+
        | Software*          | {ASCII}: name & release number of    |
        |                    | creator software                     |
        +--------------------+--------------------------------------+
        | StripByteCounts    | <n>: number or bytes in TIFF strip   |
        +--------------------+--------------------------------------+
        | StripOffsets       | <n>: offset from beginning of file to|
        |                    | each TIFF strip                      |
        +--------------------+--------------------------------------+
        | XResolution        | 100, 200, 300, 400 (written in       |
        |                    | pixels/inch)                         |
        +--------------------+--------------------------------------+
        | YResolution        | equal to XResolution (pixels must be |
        |                    | square)                              |
        +--------------------+--------------------------------------+
        | Extension Fields                                          |
        +--------------------+--------------------------------------+
        | DocumentName*      | {ASCII}: name of scanned document    |
        +--------------------+--------------------------------------+
        | PageNumber         | n,m: page number followed by total   |
        |                    | page count                           |
        +--------------------+--------------------------------------+
        | Indexed            | 0: not a palette-color image         |
        |                    | 1: palette-color image               |
        +--------------------+--------------------------------------+
        | New Fields                                                |
        +--------------------+--------------------------------------|
        | Decode             | minL, maxL, mina, maxa, minb, maxb:  |
        |                    |minimum and maximum values for L*a*b* |
        +--------------------+--------------------------------------+
        | GlobalParameters   | IFD: global parameters IFD           |
        | IFD*               |                                      |
        +-----------------------------------------------------------+

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        +--------------------+--------------------------------------+
        | ProfileType*       | n: type of data stored in TIFF file  |
        +--------------------+--------------------------------------+
        | FaxProfile*        | n: ITU-compatible fax mode           |
        +--------------------+--------------------------------------+
        | CodingMethods*     | n:compression algorithms used in     |
        |                    | file                                 |
        +--------------------+--------------------------------------+
        | VersionYear*       | byte sequence: year of ITU fax std   |
        +--------------------+--------------------------------------+

8. Mixed Raster Content Mode

   This section defines the Mixed Raster Content mode or Profile M of
   TIFF for facsimile. Implementations of this profile are required to
   implement Profiles S and C, and may optionally implement Profiles F,
   J and L.

8.1. Overview

   Unlike previous fax modes, which use a single coding method and
   spatial resolution for an entire fax page, the Mixed Raster Content
   mode [T.44] enables different coding methods and resolutions within a
   single page. For example, consider a page that contains black-and-
   white text, which is best coded with MMR or JBIG, a color bar chart,
   best coded with JBIG, and a scanned color image, best coded with
   JPEG. Similarly, while spatial resolution of 400 pixels per inch may
   be best for the black-and- white text, 200 pixel per inch is usually
   sufficient for a color image.

   Rather than applying one coding method and resolution to all
   elements, MRC allows multiple coders and resolutions within a page.
   By itself, MRC does not define any new coding methods or resolutions.
   Instead it defines a 3-layer image model for structuring and
   combining the scanned image data. The MRC 3-layer model has been
   applied here using the TIFF format to yield a data structure which
   differs from [T.44] though it applies the same coding methods, uses
   the same compressed image data stream and is consistent with the TIFF
   principle of a single IFD per image.

8.1.1. MRC 3-layer model

   The 3 layers of the MRC model are Foreground and Background, which
   are both multi-level, and Mask, which is bi-level. Each layer may
   appear only once on a page and is coded independently of the other
   two. In our earlier example, the black-and-white text could be in the
   Mask layer, the color chart in the Foreground layer, and the color
   image in the Background layer.

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   Each layer is an image and, when present, is represented by at least
   one IFD in a TIFF file. This is consistent with TIFF, which provides
   fields to define the attributes, such as resolution, image size, bits
   per sample, etc., of a single image or layer. The distribution of
   content among layers is determined by the writer, as is the choice of
   coding method, color encoding and spatial resolution for a layer.

   The final image is obtained by using the Mask layer to select pixels
   from the other two layers. When the Mask layer pixel value is 1, the
   corresponding pixel from the Foreground layer is selected; when it is
   0, the corresponding pixel from the Background layer is selected.
   Details are given in the Introduction of [T.44].

   Not all pages, and not all parts of a page, require 3 layers. If
   there is only one layer present, then that layer is the primary image
   or IFD. If there is more than one layer, then the Mask must be one of
   the layers, in which case it is the primary image and it must be page
   size.

   MRC allows a page to be split into strips, with a variable number of
   scanlines in a strip. A strip can have 1, 2 or 3 layers. A single,
   stripped layer may be stored as a single, stripped image in an IFD,
   e.g., all strips associated with the Background layer may be treated
   as a single image. Alternatively, each strip associated with a layer
   may be stored as a separate image or IFD, e.g., the Background layer
   can be composed of several images that are offset vertically with
   respect to the page. In this case, there can be no overlap between
   images associated with a single layer. According to [T.4] Annex G,
   strips having more than 1 layer SHOULD NOT be more than 256 lines in
   length unless the capability to receive longer strips has been
   negotiated.

   Furthermore, color fax also requires the spatial resolutions of
   Background and Foreground images to be legal fax values that are also
   integer factors of the Mask image resolution. For example, if the
   Mask Layer resolution is 400 pixels per inch, then allowed
   resolutions for the Foreground and Background layers are 100, 200 or
   400 pixels per inch; if the Mask is at 300 pixels per inch, then
   allowed values are 100 and 300. The Foreground and Background layer
   resolutions can be independently set.

8.1.2. A TIFF Representation for the MRC 3-layer model

   In the TIFF representation of the 3-layer MRC model, each page is
   represented by a single IFD, called the Primary IFD, that represents
   the Mask layer (unless the Foreground or Background is the single
   layer present), and a set of child IFDs that are referenced through
   the SubIFDs extension field [TTN1]. To distinguish MRC-specific

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   SubIFDs from other SubIFDs, the NewSubFileType field MUST have Bit 4
   ON, indicating an MRC-related IFD. A new ImageLayer field is also
   introduced that consists of two values that identify the layer
   (Foreground, Background, or Mask) and the order within the layer
   (first, second, ... image of the layer); see Section 8.2.3.

   Because MRC allows strips with variable numbers of scanlines, a
   reader MUST support StripRowCounts field because a writer may use it
   in place of the RowsPerStrip field in this mode. The StripRowCounts
   field allows each layer, with a variable number of scanlines in each
   strip, to be represented by a single IFD, when the coding parameters
   are the same for all strips in the layer. The MRC standard [T.44]
   allows the Foreground and Background layers to have strips with
   different coding parameters. In this case, a separate IFD is required
   to represent the strips which use different coding parameters; see
   text in next paragraph. In all cases, the Mask layer is required to
   be represented by a single IFD and a single set of coding parameters.

   The use of SubIFDs to store child IFDs is described in [TTN1]. An
   example is shown graphically below. The Primary IFD associated with
   page 1 (PrimaryIFD 0) points to page 2 (PrimaryIFD 1) with the
   nextIFD offset. The Primary IFD, corresponding to the Mask layer
   (ImageLayer=[2,1]), contains a SubIFDs field that points to a list of
   child IFDs. The first child IFD represents one image of the
   Background layer, i.e., ImageLayer=[1,1]. This child IFD points to
   the second child IFD via the nextIFD offset. This child represents
   the second Background layer image, ImageLayer=[1,2]. Finally, the
   second child points to the third child, which corresponds to the
   single Foreground layer image, ImageLayer=[3,1]. The next IFD offset
   associated with this Foreground image is 0, indicating no more child
   IFDs exist. Each primary IFD has the NewSubFileType set to 18,
   indicating the IFD is MRC-specific (bit 4) and that it is a single
   page of a multi-page document (bit 1). Each child IFD has the
   NewSubFileType set to 16, indicating the IFD is MRC-specific. The 'V'
   character should be read as a down-pointing arrow.

                       (nextIFD)
       PRIMARY IFD 0  ------------> PRIMARY IFD 1--> ...
           ImageLayer = [2,1]
           NewSubFileType = 18
           SubIFDs
                |
                V
             Child IFD
                ImageLayer = [1,1]
                NewSubFileType = 16
                |
                |(nextIFD)

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                |
                V
             Child IFD
                ImageLayer = [1,2]
                NewSubFileType = 16
                |
                |(nextIFD)
                |
                V
             Child IFD
                ImageLayer = [3,1]
                NewSubFileType = 16
                |
                |(nextIFD)
                V
                0

   In the example above, the SubIFDs field of the Primary IFD points to
   the first IFD in a list of child IFDs. TIFF allows the SubIFDs field
   to point to an array of IFDs, each of which can be the first of a
   list of IFDs. An MRC-enabled TIFF reader must scan all available
   child IFDs to locate and identify IFDs associated with MRC layers.

   In the case where the Background or Foreground layers are described
   with multiple IFDs, the XPosition and YPosition TIFF fields specify
   the offset to the upper-left corner of the IFD with respect to the
   Mask layer; see Section 8.2.2. When there is only a single layer
   (Mask, Foreground, or Background), it is stored as the Primary IFD.

8.2. Required TIFF Fields

   This section describes the TIFF fields required, in addition to those
   in Section 2.2.1, to represent MRC mode fax images. Since MRC mode
   stores fax data as a collection of images corresponding to layers or
   parts of layers, the coding methods, color encodings and spatial
   resolutions used by previous modes apply to MRC. Therefore, the
   descriptions here will typically reference the appropriate earlier
   section. Fields and values specific to MRC mode are pointed out.

8.2.1. Baseline Fields

ImageWidth(256).                                           SHORT or LONG
    Same page widths as the base color mode; see Section 6.2.1.
    In the MRC mode, the width of a Foreground or Background image in
    the coded data stream may be less than the page width. In this case,
    the image width in the coded data steam is used to interpret the
    coded data, and the value of this field is used as the page width.

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NewSubFileType(254) = 16, 18.                                       LONG
    For MRC fax mode, the NewSubFileType field has two bits that are
    required.
    Bit 1 indicates a single page of a multi-page document and must be
    set for the Primary IFD;
    Bit 4 indicates MRC imaging model as described in ITU-T
    Recommendation T.44 [T.44], and must be set for Primary IFDs
    and all MRC-specific child IFDs.

BitsPerSample(258) = 1, 2-8, 9-16                                  SHORT
Compression(259) = 3, 4, 7, 9, 10.                                 SHORT
SamplesPerPixel(277) = 1, 3, 4.                                    SHORT

FillOrder(266) = 1 , 2.                                            SHORT
    RequiredByTIFFBaseline
    Profile F readers must be able to read data in both bit orders,
    but the vast majority of facsimile products store data LSB
    first, exactly as it appears on the telephone line.
              1 = Most Significant Bit first.
              2 = Least Significant Bit first

ResolutionUnit(296) = 2, 3.                                        SHORT
PhotometricInterpretation(262) = 0, 1, 2, 5, 10.                   SHORT
    For Mask layer, see Sections 4.2.1 and 5.2.1.
    For Foreground and Background layers, see Sections 6.2.1 and 7.2.1.

ColorMap(320).                                                     SHORT
Count = 3 * (2**BitsPerSample)
    Used when Foreground or Background layer is a palette-color image;
    see Section 7.2.1.

XResolution(282) = 100, 200, 300, 400.                          RATIONAL
YResolution(283) = 100, 200, 300, 400.                          RATIONAL
    The resolution of the image is expressed in pixels per resolution
    unit. In pixels per inch, allowed XResolution values for all layers
    are: 100, 200, 300, and 400. MRC color fax mode requires the pixels
    to be square, hence YResolution must equal XResolution for all
    layers. The resolution of Background and Foreground layers must each
    be an integer factor of the Primary image, which is the Mask layer,
    when it is present; see Section 8.4.
    See Section 2.2.2 for inch-metric equivalency.

8.2.2. Extension Fields

ChromaSubSampling(530).                                            SHORT
ChromaPositioning(531).                                            SHORT
    For Foreground and Background layers, see Section 6.2.2.

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Indexed(346) = 0, 1.                                               SHORT
    For Foreground and Background layers: 1 indicates a palette-color
    image, see Section 7.2.2.

T4Options(292) = 0, 1, 4, 5.                                       SHORT
T6Options(293) = 0.                                                SHORT
    For Mask layer, see Section 4.2.2.

SubIFDs(330).                                                        IFD
    Count = number of child IFDs
    Each value is an offset from the beginning of the TIFF file to a
    child IFD [TTN1].

XPosition(286).                                                 RATIONAL
YPosition(287).                                                 RATIONAL
    Specifies the horizontal and vertical offsets of the top-left of the
    IFD from the top-left of the Primary IFD in page resolution units.
    For example, if the Primary IFD is at 400 pixels per inch, and a
    foreground layer IFD is at 200 pixels per inch and located at pixel
    coordinate (345, 678) with respect to the Primary IFD, the XPosition
    value is 345/400 and the YPosition value is 678/400.
    Color fax does not currently allow overlap of any component images
    within a single layer.
    Default values for XPosition and YPosition are 0.

8.2.3. New Fields

Decode(433).                                                   SRATIONAL
    For Foreground and Background layers, see Section 6.2.3.

DefaultImageColor(434).                                            SHORT
    Count = SamplesPerPixel
    In areas where no image data is available, a default color is needed
    to specify the color value. If the StripByteCounts value for a strip
    is 0, then the color for that strip must be defined by a default
    image color.

    The DefaultImageColor field uses the same encoding as the image
    data, and its value is therefore interpreted using the
    PhotometricInterpretation, SamplesPerPixel, BitsPerSample, and
    Indexed fields. If the fax data stream requires a different
    encoding, then transferring the default color value between a TIFF
    file and fax data stream requires a color conversion.
    For the Foreground layer image, the default value for the
    DefaultImageColor field is black. For other cases, including the
    Background layer image, the default value is white.

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StripRowCounts(559).                                                LONG
    Count = number of strips
    The number of scanlines stored in a strip. MRC allows each fax strip
    to store a different number of scanlines. For strips with more than
    one layer there is a maximum strip size of 256 scanlines or full
    page size. The 256 maximum SHOULD be used unless the capability to
    receive longer strips has been negotiated. This field replaces
    RowsPerStrip for IFDs with variable-sized strips. Only one of the
    two fields, StripRowCounts and RowsPerStrip, may be used in an IFD.

ImageLayer (34732).                                       SHORT or LONG.
    Count = 2
    Image layers are defined such that layer 1 is the Background layer,
    layer 3 is the Foreground layer, and layer 2 is the Mask layer,
    which selects pixels from the Background and Foreground layers. The
    ImageLayer tag contains two values, describing the layer to which
    the image belongs and the order in which it is imaged.

    ImageLayer[0] = 1, 2, 3.
    1: Image is a Background image, i.e., the image that will appear
       whenever the Mask contains a value of 0. Background images
       typically contain low-resolution, continuous-tone imagery.
    2: Image is the Mask layer. In MRC, if the Mask layer is present, it
       must be the Primary IFD and be full page in extent (no gaps.)
    3: Image is a Foreground image, i.e., the image that will appear
       whenever the Mask contains a value of 1. The Foreground image
       generally defines the color of text or lines, but may also
       contain high-resolution imagery.

    ImageLayer[1]:
    1: first image to be imaged in this layer,
    2: second image to be imaged in this layer,
    3: ...

    Value describing the image order. In MRC, this may be considered
    the strip number. Since MRC mode currently does not allow overlap
    between images within a layer, the order value does not have any
    visual effect.

   In MRC fax mode, it is possible that only a single layer is
   transmitted. For example, if a page contains only a single
   continuous-tone photograph, then only the Background layer may be
   transmitted. In this case, the Background layer will be stored as the
   Primary IFD. ImageLayer[0] will be 1 indicating Background;
   ImageLayer[1] will be 1 since there can be no other IFDs associated
   with that layer. No Mask layer will exist.

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8.3. Recommended TIFF Fields

   See Sections 2.2.3. and 2.2.4.

8.4. Rules and Requirements for Images

   The MRC mode defines a fundamental set of rules for images in the 3-
   layer representation.

   1. If more than one layer exists, then the binary Mask layer SHALL be
      present and be the primary image. The Mask layer SHALL support the
      encoding defined in Section 3 and MAY support the encodings
      defined in Sections 4 and 5. If only one layer exists, then the
      image corresponding to that layer is the primary image.

   2. When the binary Mask layer is the Primary IFD, the Primary IFD
      defines and extends to the entire page boundary; all attached
      model images cannot extend beyond the Primary image. Resolution
      differences may cause some pixels to "hang over" the page
      boundary, but no new pixels should exist completely beyond the
      page extent. When the Foreground or Background layer is the
      Primary IFD, the Primary IFD may not be page width.

   3. The Background and Foreground images SHALL support the color
      encoding defined in Section 6 and MAY support the color encoding
      defined in Section 7. These images MAY optionally cover only a
      portion of the strip or page.

   4. Each Primary IFD and each MRC-specific SubIFD must have an
      ImageLayer field to specify which layer the IFD belongs to, and
      the imaging order of that IFD within the layer.

   5. Each Primary IFD must have a NewSubFileType field value set to 18,
      indicating a single page of a multi-page document (bit 1) and MRC
      mode (bit 4).

   6. Each MRC-specific child IFD must have a NewSubFileType field value
      set to 16, indicating MRC mode (bit 4).

   7. In MRC mode, each layer is transmitted as a sequence of strips. It
      is possible that each strip of each layer can be stored as a
      separate IFD. In this case, the SubIFDs structure pointed to by
      the Primary IFD will contain several IFDs that have an ImageLayer
      field with the layer identified as either Background (layer 1) or
      Foreground (layer 3). There may be no overlap in the vertical
      direction between IFDs associated with a single layer, although

Top      Up      ToC       Page 63 
      there may be a gap from one of these images to the next. The TIFF
      XPosition and YPosition fields are used to indicate the placement
      of these images with respect to the primary image.

   8. When the Mask image is present, the resolution of Background and
      Foreground images must each be an integer factor of the Mask
      image. For example, if the Mask image is 400 pixels/inch, then the
      Background or Foreground image may be at 400 pixels/inch (400/1),
      200 pixels/inch (400/2) or 100 pixels/inch (400/4).

8.5. MRC Fax Mode Summary

   Recommended fields are shown with an asterisk *

       +------------------+-----------------------------------------+
       | Baseline Fields  |               Values                    |
       |------------------|-----------------------------------------|
       | BitsPerSample    | 1: binary mask                          |
       |                  | 8: 8 bits per color sample              |
       |                  | 9-16: optional 12 bits/sample           |
       +------------------+-----------------------------------------+
       | ColorMap         | n: LAB color map                        |
       +------------------+-----------------------------------------+
       | Compression      | 3: Modified Huffman and Modified Read   |
       |                  | 4: Modified Modified Read               |
       |                  | 7: JPEG                                 |
       |                  | 9: JBIG, per T.85                       |
       |                  | 10: JBIG, per T.43                      |
       +------------------+-----------------------------------------+
       | DateTime*        | {ASCII): date/time in the 24-hour format|
       |                  | "YYYY:MM:DD HH:MM:SS"                   |
       +------------------+-----------------------------------------|
       | FillOrder**      | 1: Most significant bit first           |
       |                  | 2: Least significant bit first          |
       +------------------+-----------------------------------------|
       | ImageDescription*| {ASCII}: A string describing the        |
       |                  | contents of the image.                  |
       +------------------+-----------------------------------------+
       | ImageWidth       | 864, 1024, 1216, 1728**, 2048, 2432,    |
       |                  | 2592, 3072, 3456, 3648, 4096, 4864      |
       +------------------+-----------------------------------------+
       | ImageLength**    | n: total number of scanlines in image   |
       +------------------+-----------------------------------------+
       | NewSubFileType   | 16, 18:                                 |
       |                  | Bit 1 indicates single page of a multi- |
       |                  | page document on Primary IFD            |
       |                  | Bit 4 indicates MRC model               |
       +------------------+-----------------------------------------+

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       +------------------+-----------------------------------------+
       | Orientation      | 1**-8, Default 1                        |
       +------------------+-----------------------------------------+
       | PhotometricInter | 0: WhiteIsZero                          |
       | pretation        | 1: BlackIsZero                          |
       |                  | 2: RGB                                  |
       |                  | 5: CMYK                                 |
       |                  | 10: ITULAB                              |
       +------------------+-----------------------------------------+
       | ResolutionUnit   | 2: inch                                 |
       |                  | 3: centimeter                           |
       +------------------+-----------------------------------------+
       | RowsPerStrip     | n: number or scanlines per strip        |
       +------------------+-----------------------------------------+
       | SamplesPerPixel  | 1: L* (lightness)                       |
       |                  | 3: RGB, LAB, CMY                        |
       |                  | 4: CMYK                                 |
       +------------------+-----------------------------------------+
       | Software*        | {ASCII}: name & release number of       |
       |                  | creator software                        |
       +------------------+-----------------------------------------+
       | StripByteCounts  | <n>: number or bytes in each strip      |
       +------------------+-----------------------------------------+
       | StripOffsets     | <n>: offset from beginning of file to   |
       |                  | each TIFF strip                         |
       +------------------+-----------------------------------------|
       | XResolution      | 100, 200, 300, 400 (written in          |
       |                  | pixels/inch)                            |
       +------------------+-----------------------------------------|
       | YResolution      | equal to XResolution (pixels must be    |
       |                  | square)                                 |
       +------------------+-----------------------------------------+
       | Extension Fields                                           |
       +------------------+-----------------------------------------+
       | T4Options        | 0: required if Compression is Modified  |
       |                  | Huffman, EOLs not byte aligned          |
       |                  | 1: required if Compression 2D Modified  |
       |                  | Read, EOLs are not byte aligned         |
       |                  | 4: required if Compression Modified     |
       |                  | Huffman, EOLs byte aligned              |
       |                  | 5: required if Compression 2D Modified  |
       |                  | Read, EOLs are byte aligned             |
       +------------------+-----------------------------------------+
       | T6Options        | 0: required if Compression is 2D        |
       |                  | Modified Modified Read                  |
       +------------------+-----------------------------------------+

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       +------------------+-----------------------------------------+
       | DocumentName*    | {ASCII}: name of scanned document       |
       +------------------+-----------------------------------------+
       | PageNumber       | n,m: page number followed by total page |
       |                  | count                                   |
       +------------------+-----------------------------------------+
       | ChromaSubSampling| (1,1), (2, 2)**                         |
       |                  | (1, 1): equal numbers of lightness and  |
       |                  | chroma samples horizontally & vertically|
       |                  | (2, 2): twice as many lightness samples |
       |                  | as chroma horizontally and vertically   |
       +------------------+-----------------------------------------+
       | ChromaPositioning| 1: centered                             |
       +------------------+-----------------------------------------+
       | Indexed          | 0: not a palette-color image            |
       |                  | 1: palette-color image                  |
       +------------------+-----------------------------------------+
       | SubIFDs          | <IFD>: byte offset to fg/bg IFDs        |
       +------------------+-----------------------------------------+
       | XPosition        | horizontal offset in primary IFD        |
       |                  | resolution units                        |
       +------------------+-----------------------------------------+
       | YPosition        | vertical offset in primary IFD          |
       |                  | resolution units                        |
       +------------------+-----------------------------------------+
       | New Fields                                                 |
       +------------------+-----------------------------------------+
       | Decode           | minL, maxL, mina, maxa, minb, maxb:     |
       |                  | minimum and maximum values for L*a*b*   |
       +------------------+-----------------------------------------+
       | DefaultImageColor| <n>: background color                   |
       +------------------+-----------------------------------------+
       | StripRowCounts   | <n>: number of scanlines in each strip  |
       +------------------+-----------------------------------------+
       | ImageLayer       | n, m: layer number, imaging sequence    |
       |                  | (e.g., strip number)                    |
       +------------------+-----------------------------------------+
       | GlobalParameters | IFD: global parameters IFD              |
       | IFD*             |                                         |
       +------------------+-----------------------------------------+
       | ProfileType*     | n: type of data stored in TIFF file     |
       +------------------+-----------------------------------------+
       | FaxProfile*      | n: ITU-compatible fax mode              |
       +------------------+-----------------------------------------+
       | CodingMethods*   | n: compression algorithms used in file  |
       +------------------+-----------------------------------------+
       | ModeNumber*      | n: version of ITU fax standard          |
       +------------------+-----------------------------------------+

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       +------------------------------------------------------------+
       | VersionYear*     | byte sequence: year of ITU fax standard |
       +------------------+-----------------------------------------+

9. MIME content-type image/tiff

   [TIFF-REG] describes the registration of the MIME content-type
   image/tiff to refer to TIFF encoded image data. When transported by
   MIME, the TIFF content defined by this document must be encoded
   within an image/tiff content type. In addition, an optional
   "application" parameter is defined for image/tiff to identify a
   particular application's subset of TIFF and TIFF extensions for the
   encoded image data, if it is known. Typically, this would be used to
   assist the recipient in dispatching a suitable rendering package to
   handle the display or processing of the image file.

9.1 Refinement of MIME content-type image/tiff for Facsimile
   Applications

   Since this document defines facsimile specific profiles of TIFF, it
   is useful to note an appropriate application parameter for the
   image/tiff MIME content-type.

   The two values of the image/tiff application parameter as defined for
   facsimile are shown below, separated by a comma:

       faxbw, faxcolor

   The "faxbw" application parameter is suitable for use by applications
   that can process one or more TIFF for facsimile profiles or subsets
   used for the encoding of black and white facsimile data.

   The "faxcolor" application parameter is suitable for use by
   applications that can process one or more TIFF for facsimile profiles
   or subsets that can be used for the encoding of black and white, AND
   color facsimile data.

   Since this document defines several profiles of TIFF for facsimile,
   the following rules should be followed when setting the application
   parameter value. For TIFF image data which is encoded for the
   profiles of TIFF for Facsimile that support black-and-white image
   data (Profiles S, F or J), applications which use one of these
   profiles or a subset should set the value of the application
   parameter to "faxbw". For TIFF image data which is encoded for the
   defined profiles of TIFF for Facsimile that support color image data
   (Profiles C, L or M), as well as black-and-white image data,
   applications which use one of these profiles or a subset should set
   the value of the application parameter to "faxcolor".

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   An example of the use of the image/tiff MIME Content-type with the
   application parameter set with the value 'faxbw' follows:

       Content-type: image/tiff; application=faxbw

   In this example, use of this parameter value will enable applications
   to identify the content as being within a profile or subset of TIFF
   for Facsimile that is suitable for encoding black and white image
   data, Before attempting to process the image data.

   In a similar respect, an example of the image/tiff MIME Content-type
   with the application parameter setting suitable for handling a color
   subset or profile of TIFF for facsimile is shown below:

       Content-type: image/tiff; application=faxcolor

10. Security Considerations

   This document describes a file format for Internet fax, which is a
   series of profiles of TIFF for facsimile. As such, it does not create
   any security issues not already identified in [TIFF-REG], in its use
   of fields as defined in [TIFF].  There are also new TIFF fields
   defined within this specification, but they are of a purely
   descriptive nature, so that no new security risks are incurred.

   Further, the encoding specified in this document does not in any way
   preclude the use of any Internet security protocol to encrypt,
   authenticate, or non-repudiate TIFF-encoded facsimile messages.

11. References

   [REQ] Bradner, S, "Key words for use in RFCs to Indicate Requirement
   Levels", RFC 2119, March 1997.

   [T.4] ITU-T Recommendation T.4, Standardization of group 3 facsimile
   apparatus for document transmission, October 1997

   [T.6] ITU-T Recommendation T.6, Facsimile coding schemes and coding
   control functions for group 4 facsimile apparatus, November 1988

   [T.30] ITU-T Recommendation T.30 - Procedures for Document Facsimile
   Transmission in the General Switched Telephone Network, June 1996

   [T.42] ITU-T Recommendation T.42, Continuous-tone colour
   representation method for facsimile, February 1996

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   [T.43] ITU-T Recommendation T.43, Colour and gray-scale image
   representations using lossless coding scheme for facsimile, February
   1997

   [T.44] ITU-T Recommendation T.44, Mixed Raster Content (MRC), October
   1997.

   [T.81] ITU-T Recommendation T.81, Information technology - Digital
   compression and coding of continuous-tone still images - Requirements
   and guidelines, September 1992

   [T.82] ITU-T Recommendation T.82, Information technology - Coded
   representation of picture and audio information - Progressive bi-
   level image compression, March 1995

   [T.85] ITU-T Recommendation T.85, Application profile for
   Recommendation T.82 - Progressive bi-level image compression (JBIG
   coding scheme) for facsimile apparatus, August 1995

   [TIFF] Tag Image File Format, Revision 6.0, Adobe Developers
   Association, June 3, 1992,
   ftp://ftp.adobe.com/pub/adobe/devrelations/
   devtechnotes/pdffiles/tiff6.pdf

        The TIFF 6.0 specification dated June 3, 1992 specification (c)
        1986-1988, 1992 Adobe Systems Incorporated. All Rights Reserved.

   [TIFF-FY] Parsons, G.  and J. Rafferty, "Tag Image File Format (TIFF)
   - F Profile for Facsimile", RFC 2306, March 1998.

   [TIFF-F0] TIFF Class F specification, Apr 28, 1990,
   ftp://ftp.faximum.com/pub/documents/tiff_f.txt

   [TIFF-REG] Parsons, G., Rafferty J. and S. Zilles, "Tag Image File
   Format (TIFF) - image/tiff MIME Sub-type Registration",  RFC 2302,
   March 1998.

   [TTN1] Adobe PageMaker 6.0 TIFF Technical Notes, Sept. 14, 1995,
   http://www.adobe.com/supportservice/devrelations/PDFS/TN/TIFFPM6.pdf

   [TTN2] Draft TIFF Technical Note 2, Replacement TIFF/JPEG
   specification, March 17, 1995,
   ftp://ftp.sgi.com/graphics/tiff/TTN2.draft.txt

   [VPIM2] Vaudreui,l G. and G. Parsons, "Voice Profile for Internet
   Mail - version 2", work in progress, <draft-ema-vpim-06.txt>

   The ITU-T Recommendations are available at http://www.itu.ch.

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12. Authors' Addresses

   Lloyd McIntyre                     Stephen Zilles
   Xerox Corporation                  Adobe Systems Inc.
   Mailstop PAHV-305                  Mailstop W14
   3400 Hillview Ave.                 345 Park Avenue
   Palo Alto, CA 94304 USA            San Jose, CA 95110-2704, USA
   Voice: +1-650-813-6762             Voice: +1-408-536-4766
   Fax: +1-650-845-2340               Fax: +1-408-536-4042
   Email: lmcintyre@adoc.xerox.com    Email: szilles@adobe.com

   Robert Buckley                     Dennis Venable
   Xerox Corporation                  Xerox Corporation
   Mailstop 0128-30E                  Mailstop 0128-27E
   800 Phillips Road                  800 Phillips Road
   Webster, NY 14580, USA             Webster, NY 14580, USA
   Voice: +1-716-422-1282             Voice: +1-716-422-8009
   Fax: +1-716-422-6117               Fax: +1-716-422-6117
   Email: Rob_Buckley@wb.xerox.com    Email: venable@wrc.xerox.com

   Glenn S. Parsons                   James Rafferty
   Northern Telecom                   Human Communications
   P.O. Box 3511, Station C           12 Kevin Drive
   Ottawa, ON  K1Y 4H7, Canada        Danbury, CT 06811-2901, USA
   Phone: +1-613-763-7582             Phone: +1-203-746-4367
   Fax: +1-613-763-2697               Fax: +1-203-746-4367
   Email: Glenn.Parsons@Nortel.ca     Email: Jrafferty@worldnet.att.net

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Annex A:  Summary of TIFF Fields for Internet Fax

   This annex includes tables which list by mode the TIFF fields used in
   the proposed fax file format.  The fields are organized into 3
   categories:

      1)  TIFF Baseline Fields
      2)  TIFF Extension Fields
      3)  New Fields.

   The tables include the allowed values for each fax mode. Entries
   other than explicit numbers are described by:

      n        - single number
      n, m     - 2 numbers
      a, b, c  - 3 numbers
      r        - rational number
      <n>      - array of numbers
      <b>      - byte sequence
      {ASCII}  - string
      IFD      - IFD byte offset
      <IFD>    - array of IFD byte offsets

   A blank entry in the table indicates that the field is not used by
   that particular fax mode.

Table A.1  TIFF Baseline Fields

            +---------------------------------------------------------+
            |                    Fax Mode/Profile                     |
            +---------------------------------------------------------|
            | Minimal | Extended |  JBIG  |  Lossy  |Lossless| Mixed  |
 +----------|   B&W   |    B&W   |  B&W   |  Color  | Color  | Raster |
 |   TIFF   |         |          |        |         |        | Content|
 |  Field   |    S    |     F    |   J    |    C    |   L    |   M    |
 +----------+---------+----------+--------+---------+--------+--------+
 | BitsPer  | 1       | 1        | 1      | 8, 12   | 1, 2-8 | 1, 2-8 |
 | Sample   |         |          |        |         | 9-16   | 9-16   |
 +----------+---------+----------+--------+---------+--------+--------+
 | ColorMap |         |          |        |         | <n>    | <n>    |
 +----------+---------+----------+--------+---------+--------+--------+
 | Compres- | 3       | 3, 4     | 9      | 7       | 10     | 3, 4, 7|
 | sion     |         |          |        |         |        | 9,10   |
 +----------+---------+----------+--------+---------+--------+--------+
 | DateTime |         | {ASCII}  | {ASCII}| {ASCII} | {ASCII}| {ASCII}|
 +----------+---------+----------+--------+---------+--------+--------+
 | FillOrder| 2       | 1, 2     | 1, 2   | 1, 2    | 1, 2   | 1,2    |
 +----------+---------+----------+--------+---------+--------+--------+

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 +----------+---------+----------+--------+---------+--------+--------+
 | ImageDes-|         | {ASCII}  | {ASCII}| {ASCII} | {ASCII}| {ASCII}|
 | cription |         |          |        |         |        |        |
 +----------+---------+----------+--------+---------+--------+--------+
 | Image-   | n       | n        | n      | n       | n      | n      |
 | Length   |         |          |        |         |        |        |
 +----------+---------+----------+--------+---------+--------+--------+
 | Image-   | 1728    | 1728, 2048, 2432  |   864, 1024, 1216, 1728,  |
 | Width    |         | 2592, 3072, 3456  |  2048, 2432, 2592, 3072,  |
 |          |         | 3648, 4096, 4864  |  3456, 3648, 4096, 4864   |
 +----------+---------+----------+--------+---------+--------+--------+
 | NewSub-  | 2       | 2        | 2      | 2       | 2      | 16, 18 |
 | FileType |         |          |        |         |        |        |
 +----------+---------+----------+--------+---------+--------+--------+
 | Orien-   | 1       | 1-8      | 1-8    | 1-8     | 1-8    | 1-8    |
 | tation   |         |          |        |         |        |        |
 +----------+---------+----------+--------+---------+--------+--------+
 | Photo-   | 0       | 0, 1     | 0, 1   | 10      | 2, 5,  | 0, 1,  |
 | metric-  |         |          |        |         | 10     | 2, 5,  |
 | Interp-  |         |          |        |         |        | 10     |
 | retation |         |          |        |         |        |        |
 +----------+---------+----------+--------+---------+--------+--------+
 | Resolu-  | 2       | 2, 3     | 2, 3   | 2, 3    | 2, 3   | 2, 3   |
 | tionUnit |         |          |        |         |        |        |
 +----------+---------+----------+--------+---------+--------+--------+
 | RowsPer- | n       | n        | n      | n       | n      | n      |
 | Strip    |         |          |        |         |        |        |
 +----------+---------+----------+--------+---------+--------+--------+
 | Samples- | 1       | 1        | 1      | 1, 3    | 1, 3, 4| 1, 3, 4|
 | PerPixel |         |          |        |         |        |        |
 +----------+---------+----------+--------+---------+--------+--------+
 | Software |         | {ASCII}  | {ASCII}| {ASCII} | {ASCII}| {ASCII}|
 +----------+---------+----------+--------+---------+--------+--------+
 | Strip-   | n       | <n>      | <n>    | <n>     | <n>    | <n>    |
 | Byte-    |         |          |        |         |        |        |
 | Counts   |         |          |        |         |        |        |
 +----------+---------+----------+--------+---------+--------+--------+
 | Strip-   | n       | <n>      | <n>    | <n>     | <n>    | <n>    |
 | Offsets  |         |          |        |         |        |        |
 +----------+---------+----------+--------+---------+--------+--------+
 | XResolu- | 204     | 200, 204, 300     |    100, 200, 300, 400     |
 | tion     | 200     | 400, 408          |                           |
 +----------+---------+----------+--------+---------+--------+--------+
 | YResolu- | 98, 196 | 98, 196, 100, 200 |    100, 200, 300, 400     |
 | tion     | 100,200 | 300, 391, 400     |                           |
 +----------+---------+----------+--------+---------+--------+--------+

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Table A.2  TIFF Extension Fields

            +---------------------------------------------------------+
            |                    Fax Mode/Profile                     |
            +---------------------------------------------------------|
            | Minimal | Extended |  JBIG  |  Lossy  |Lossless| Mixed  |
 +----------|   B&W   |    B&W   |  B&W   |  Color  | Color  | Raster |
 |   TIFF   |         |          |        |         |        | Content|
 |  Field   |    S    |     F    |   J    |    C    |   L    |   M    |
 +----------+---------+----------+--------+---------+--------+--------+
 | Chroma-  |         |          |        | 1       |        | 1      |
 | Position-|         |          |        |         |        |        |
 | ing      |         |          |        |         |        |        |
 +----------+---------+----------+--------+---------+--------+--------+
 | Chroma-  |         |          |        | <1, 1>  |        | <1, 1> |
 | SubSampl-|         |          |        | <2, 2>  |        | <2, 2> |
 | ing      |         |          |        |         |        |        |
 +----------+---------+----------+--------+---------+--------+--------+
 | Document-|         | {ASCII}  | {ASCII}| {ASCII} | {ASCII}| {ASCII}|
 | Name     |         |          |        |         |        |        |
 +----------+---------+----------+--------+---------+--------+--------+
 | Indexed  |         |          |        |         | 0,1    | 0,1    |
 +----------+---------+----------+--------+---------+--------+--------+
 | Page-    | n, m    | n, m     | n, m   | n, m    | n, m   | n, m   |
 | Number   |         |          |        |         |        |        |
 +----------+---------+----------+--------+---------+--------+--------+
 | SubIFDs  |         |          |        |         |        | <IFD>  |
 +----------+---------+----------+--------+---------+--------+--------+
 | T4Options| 0, 4    | 0, 1,    |        |         |        | 0, 1,  |
 |          |         | 4, 5     |        |         |        | 4, 5   |
 +----------+---------+----------+--------+---------+--------+--------+
 | T6Options|         | 0        |        |         |        | 0      |
 +----------+---------+----------+--------+---------+--------+--------+
 | XPosition|         |          |        |         |        | r      |
 +----------+---------+----------+--------+---------+--------+--------+
 | YPosition|         |          |        |         |        | r      |
 +----------+---------+----------+--------+---------+--------+--------+

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Table A.3   New Fields

            +---------------------------------------------------------+
            |                    Fax Mode/Profile                     |
            +---------------------------------------------------------|
            | Minimal | Extended |  JBIG  |  Lossy  |Lossless| Mixed  |
 +----------|   B&W   |    B&W   |  B&W   |  Color  | Color  | Raster |
 |   TIFF   |         |          |        |         |        | Content|
 |  Field   |    S    |     F    |   J    |    C    |   L    |   M    |
 +----------+---------+----------+--------+---------+--------+--------+
 | BadFax-  |         | n        |        |         |        |        |
 | Lines    |         |          |        |         |        |        |
 +----------+---------+----------+--------+---------+--------+--------+
 | CleanFax-|         | 0, 1, 2  |        |         |        |        |
 | Data     |         |          |        |         |        |        |
 +----------+---------+----------+--------+---------+--------+--------+
 | Coding-  |         |          | n      | n       | n      | n      |
 | Method   |         |          |        |         |        |        |
 +----------+---------+----------+--------+---------+--------+--------+
 | Consecu- |         | n        |        |         |        |        |
 | tiveBad- |         |          |        |         |        |        |
 | FaxLines |         |          |        |         |        |        |
 +----------+---------+----------+--------+---------+--------+--------+
 | Decode   |         |          |        | <r>     | <r>    | <r>    |
 +----------+---------+----------+--------+---------+--------+--------+
 | Default- |         |          |        |         |        | <n>    |
 |ImageColor|         |          |        |         |        |        |
 +----------+---------+----------+--------+---------+--------+--------+
 | Fax-     |         |          | n      | n       | n      | n      |
 | Profile  |         |          |        |         |        |        |
 +----------+---------+----------+--------+---------+--------+--------+
 | Global-  |         | IFD      | IFD    | IFD     | IFD    | IFD    |
 | Parame-  |         |          |        |         |        |        |
 | tersIFD  |         |          |        |         |        |        |
 +----------+---------+----------+--------+---------+--------+--------+
 | Image-   |         |          |        |         |        | n, m   |
 | Layer    |         |          |        |         |        |        |
 +----------+---------+----------+--------+---------+--------+--------+
 | Mode-    |         |          |        |         |        | n      |
 | Number   |         |          |        |         |        |        |
 +----------+---------+----------+--------+---------+--------+--------|
 | Profile- |         |          | n      | n       | n      | n      |
 | Type     |         |          |        |         |        |        |
 +--------------------------------------------------------------------+

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 +----------+---------+----------+--------+---------+--------+--------+
 | Strip-   |         |          |        |         |        | <n>    |
 | RowCounts|         |          |        |         |        |        |
 +----------+---------+----------+--------+---------+--------+--------+
 | Version- |         |          |        | <b>     |<b>     |        |
 | Year     |         |          |        |         |        |        |
 +----------+---------+----------+--------+---------+--------+--------+

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Annex B.  IANA Registration for image/tiff Application Parameter
Values used for facsimile

   To: IANA@isi.edu

   Subject: Registration of new Application parameter values for
   image/tiff

   MIME media type name: image/tiff

   Optional parameters: Application

   New Value(s): faxbw, faxcolor

   Description of Use:

   faxbw - The "faxbw" application parameter is suitable for use by
   applications that can process one or more TIFF for facsimile profiles
   or subsets used for the encoding of black-and-white facsimile data.
   The definition of the use of this value is contained in Section 9 of
   this document (TIFFPLUS).

   Faxcolor - The "faxcolor" application parameter is suitable for use
   by applications that can process one or more TIFF for facsimile
   profiles or subsets that can be used for the encoding of black and
   white, AND color facsimile data. The definition of the use of this
   value is contained in Section 9 of this document (TIFFPLUS).

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Security Considerations:

   Security considerations related to use of the TIFF subsets described
   by the "faxbw" and "faxcolor" values of the Application parameter are
   identified in Section 10 of this document (TIFFPLUS).

Persons & email addresses to contact for further information:

   Glenn W. Parsons (Glenn.Parsons@Nortel.ca)
   James Rafferty (Jrafferty@worldnet.att.net)
   Stephen Zilles (szilles@adobe.com)

   Change Controller:  Stephen Zilles

INFORMATION TO THE SUBMITTER:

   The accepted registrations will be listed in the "Assigned Numbers"
   series of RFCs.  The information in the registration form is freely
   distributable.

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Full Copyright Statement

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