TIFF 6.0 Specification Coverage

This documentation is best viewed using a graphical browser that supports the latest HTML directives for formatting documents. In particular, this document was authored for viewing with version 1.1 or newer of the Netscape Navigator.

The library is capable of dealing with images that are written to follow the 5.0 or 6.0 TIFF spec. There is also considerable support for some of the more esoteric portions of the 6.0 TIFF spec.

Core requirements Both "MM" and "II" byte orders are handled. Both packed and separated planar configuration of samples. Any number of samples per pixel (memory permitting). Any image width and height (memory permitting). Multiple subfiles can be read and written. Editing is not supported in that related subfiles (e.g. a reduced resolution version of an image) are not automatically updated.

Tags handled: ExtraSamples, ImageWidth, ImageLength, NewSubfileType, ResolutionUnit. Rowsperstrip, StripOffsets, StripByteCounts, XResolution, YResolution,

Tiled Images TileWidth, TileLength, TileOffsets, TileByteCounts
Image Colorimetry Information WhitePoint, PrimaryChromaticities, TransferFunction, ReferenceBlackWhite
Class B for bilevel images SamplesPerPixel = 1
BitsPerSample = 1
Compression = 1 (none), 2 (CCITT 1D), or 32773 (PackBits)
PhotometricInterpretation = 0 (Min-is-White), 1 (Min-is-Black)
Class G for grayscale images SamplesPerPixel = 1
BitsPerSample = 4, 8
Compression = 1 (none) 5 (LZW)
PhotometricInterpretation = 0 (Min-is-White), 1 (Min-is-Black)
Class P for palette color images SamplesPerPixel = 1
BitsPerSample = 1-8
Compression = 1 (none) 5 (LZW)
PhotometricInterpretation = 3 (Palette RGB)
Class R for RGB full color images SamplesPerPixel = 3
BitsPerSample = <8,8,8>
PlanarConfiguration = 1, 2
Compression = 1 (none) 5 (LZW)
PhotometricInterpretation = 2 (RGB)
Class F for facsimile (Class B tags plus...)
Compression = 3 (CCITT Group 3), 4 (CCITT Group 4)
FillOrder = 1 (MSB), 2 (LSB)
Group3Options = 1 (2d encoding), 4 (zero fill), 5 (2d+fill)
ImageWidth = 1728, 2048, 2482
NewSubFileType = 2
ResolutionUnit = 2 (Inch), 3 (Centimeter)
PageNumber, XResolution, YResolution, Software, BadFaxLines, CleanFaxData, ConsecutiveBadFaxLines, DateTime, DocumentName, ImageDescription, Orientation
Class S for separated images SamplesPerPixel = 4
PlanarConfiguration = 1, 2
Compression = 1 (none), 5 (LZW)
PhotometricInterpretation = 5 (Separated)
InkSet = 1 (CMYK)
DotRange, InkNames, DotRange, TargetPrinter
Class Y for YCbCr images SamplesPerPixel = 3
BitsPerSample = <8,8,8>
PlanarConfiguration = 1, 2
Compression = 1 (none), 5 (LZW), 7 (JPEG)
PhotometricInterpretation = 6 (YCbCr)
YCbCrCoefficients, YCbCrSubsampling, YCbCrPositioning
(colorimetry info from Appendix H; see above)
Class "JPEG" for JPEG images (per TTN2) PhotometricInterpretation = 1 (grayscale), 2 (RGB), 5 (CMYK), 6 (YCbCr)
(Class Y tags if YCbCr)
(Class S tags if CMYK)
Compression = 7 (JPEG)

In addition, the library supports some optional compression algorithms that are, in some cases, of dubious value.

      Compression = 32766	NeXT 2-bit encoding
      Compression = 32809	ThunderScan 4-bit encoding
      Compression = 32909	Pixar companded 11-bit ZIP encoding
      Compression = 34999	PKZIP-style Deflate encoding (experimental)
Note that there is no support for the JPEG-related tags defined in the 6.0 specification; the JPEG support is based on the post-6.0 proposal given in TIFF Technical Note #2.

The following table shows the tags that are recognized and how they are used by the library. If no use is indicated, then the library reads and writes the tag, but does not use it internally.

Tag Name Value R/W Library's Use (Comments)
NewSubFileType 254 R/W none (called SubFileType in <tiff.h>)
SubFileType 255 R/W none (called OSubFileType in <tiff.h>)
ImageWidth 256 R/W lots
ImageLength 257 R/W lots
BitsPerSample 258 R/W lots
Compression 259 R/W to select appropriate codec
PhotometricInterpretation 262 R/W lots
Thresholding 263 R/W  
CellWidth 264   parsed but ignored
CellLength 265   parsed but ignored
FillOrder 266 R/W control bit order
DocumentName 269 R/W  
ImageDescription 270 R/W  
Make 271 R/W  
Model 272 R/W  
StripOffsets 273 R/W data i/o
Orientation 274 R/W  
SamplesPerPixel 277 R/W lots
RowsPerStrip 278 R/W data i/o
StripByteCounts 279 R/W data i/o
MinSampleValue 280 R/W  
MaxSampleValue 281 R/W  
XResolution 282 R/W  
YResolution 283 R/W used by Group 3 2d encoder
PlanarConfiguration 284 R/W data i/o
PageName 285 R/W  
XPosition 286 R/W  
YPosition 286 R/W  
FreeOffsets 288   parsed but ignored
FreeByteCounts 289   parsed but ignored
GrayResponseUnit 290   parsed but ignored
GrayResponseCurve 291   parsed but ignored
Group3Options 292 R/W used by Group 3 codec
Group4Options 293 R/W  
ResolutionUnit 296 R/W used by Group 3 2d encoder
PageNumber 297 R/W  
ColorResponseUnit 300   parsed but ignored
TransferFunction 301 R/W  
Software 305 R/W  
DateTime 306 R/W  
Artist 315 R/W  
HostComputer 316 R/W  
Predictor 317 R/W used by LZW codec
WhitePoint 318 R/W  
PrimaryChromacities 319 R/W  
ColorMap 320 R/W  
TileWidth 322 R/W data i/o
TileLength 323 R/W data i/o
TileOffsets 324 R/W data i/o
TileByteCounts 324 R/W data i/o
BadFaxLines 326 R/W  
CleanFaxData 327 R/W  
ConsecutiveBadFaxLines 328 R/W  
SubIFD 330 R/W subimage descriptor support
InkSet 332 R/W  
InkNames 333 R/W  
DotRange 336 R/W  
TargetPrinter 337 R/W  
ExtraSamples 338 R/W lots
SampleFormat 339 R/W  
SMinSampleValue 340 R/W  
SMaxSampleValue 341 R/W  
JPEGTables 347 R/W used by JPEG codec
YCbCrCoefficients 529 R/W used by TIFFReadRGBAImage support
YCbCrSubsampling 530 R/W tile/strip size calculations
YCbCrPositioning 531 R/W  
ReferenceBlackWhite 532 R/W  
Matteing 32995 R none (obsoleted by ExtraSamples tag)
DataType 32996 R none (obsoleted by SampleFormat tag)
ImageDepth 32997 R/W tile/strip calculations
TileDepth 32998 R/W tile/strip calculations

The Matteing and DataType tags have been obsoleted by the 6.0 ExtraSamples and SampleFormat tags. Consult the documentation on the ExtraSamples tag and Associated Alpha for elaboration. Note however that if you use Associated Alpha, you are expected to save data that is pre-multipled by Alpha. If this means nothing to you, check out Porter & Duff's paper in the '84 SIGGRAPH proceedings: "Compositing Digital Images".

The ImageDepth tag is a non-standard, but registered tag that specifies the Z-dimension of volumetric data. The combination of ImageWidth, ImageLength, and ImageDepth, defines a 3D volume of pixels that are further specified by BitsPerSample and SamplesPerPixel. The TileDepth tag (also non-standard, but registered) can be used to specified a subvolume "tiling" of a volume of data.

The Colorimetry, and CMYK tags are additions that appear in TIFF 6.0. Consult the TIFF 6.0 specification included in the doc directory and online.

The JPEG-related tag is specified in TIFF Technical Note #2 which defines a revised JPEG-in-TIFF scheme (revised over that appendix that was part of the TIFF 6.0 specification).

Sam Leffler / sam@engr.sgi.com. Last updated: $Date: 1997/04/04 21:09:45 $