LibTIFF Coverage of the TIFF 6.0 Specification

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.

Baseline

Core requirements

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) ColorMap
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 algorithms

Compression tag value	Compression algorithm
32766	NeXT 2-bit encoding
32809	ThunderScan 4-bit encoding
32909	Pixar companded 11-bit ZIP encoding
32946	PKZIP-style Deflate encoding (experimental)
34676	SGI 32-bit Log Luminance encoding (experimental)
34677	SGI 24-bit Log Luminance 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.

Note

For more information on the experimental Log Luminance encoding consult the materials available at http://www.anyhere.com/gward/pixformat/tiffluv.html.

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. For the meaning of the tags look in https://www.awaresystems.be/imaging/tiff/tifftags.html

libtiff supports also many private tags allocated for organizations that wish to store additional information in a TIFF file. Tags for TIFF/EP and for Digital Negative (DNG) Specification 1.1.0 are included.

Note that some tags are meaningful only when a particular compression scheme is being used; e.g. Group3Options is only useful if Compression is set to CCITT Group 3 encoding. Tags of this sort are considered codec-specific tags and the library does not recognize them except when the Compression tag has been previously set to the relevant compression scheme.

Tags Recognized by LibTIFF

Tags used by libtiff

Tag Name	Value	R/W<	Library's Use (Comments)
SubfileType	254	R/W	none (also known as NewSubfileType)
OldSubfileType	255	R/W	parsed but ignored (also known as SubFileType)
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	(tag in tif.h wrongly written as "Threshholding")
CellWidth	264	R/W
CellLength	265	R/W
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	287	R/W
FreeOffsets	288	R/W	parsed but ignored
FreeByteCounts	289	R/W	parsed but ignored
GrayResponseUnit	290	R/W	parsed but ignored
GrayResponseCurve	291	R/W	parsed but ignored
ResolutionUnit	296	R/W	used by Group 3 2d encoder
PageNumber	297	R/W
ColorResponseUnit	300	R/W	parsed but ignored
TransferFunction	301	R/W
Software	305	R/W
DateTime	306	R/W
Artist	315	R/W
HostComputer	316	R/W
WhitePoint	318	R/W
PrimaryChromaticities	319	R/W
ColorMap	320	R/W
HalftoneHints	321	R/W
TileWidth	322	R/W	data i/o
TileLength	323	R/W	data i/o
TileOffsets	324	R/W	data i/o
TileByteCounts	325	R/W	data i/o
SubIFD	330	R/W	subimage descriptor support
InkSet	332	R/W
InkNames	333	R/W
NumberOfInks	334	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
ClipPath	343	R/W
XClipPathUnits	344	R/W
YClipPathUnits	345	R/W
YCbCrCoefficients	529	R/W	used by TIFFReadRGBAImage support
YCbCrSubsampling	530	R/W	tile / strip size calculations
YCbCrPositioning	531	R/W
ReferenceBlackWhite	532	R/W
XMLPacket	700	R/W
Matteing	32995	R	none (obsoleted by ExtraSamples tag)
DataType	32996	R	none (obsoleted by SampleFormat tag)
ImageDepth	32997	R/W	tile / strip size calculations
TileDepth	32998	R/W	tile / strip size calculations
ImageFullWidth	33300	R/W
ImageFullLength	33301	R/W
TextureFormat	33302	R/W
TextureWrapModes	33303	R/W
FieldOfViewCotangent	33304	R/W
MatrixWorldToScreen	33305	R/W
MatrixWorldToCamera	33306	R/W
Copyright	33432	R/W
RichTIFFIPTC	33723	R/W	(also known as TIFF/EP IPTC/NAA; libtiff type is UNDEFINED or BYTE, but often times incorrectly specified as LONG, because TIFF/EP (ISO/DIS 12234-2) specifies type LONG or ASCII)
Photoshop	34377	R/W
EXIFIFDOffset	34665	R/W
ICC Profile	34675	R/W
GPSIFDOffset	34853	R/W
FaxRecvParams	34908	R/W
FaxSubAddress	34909	R/W
FaxRecvTime	34910	R/W
FaxDcs	34911	R/W
StoNits	37439	R/W
Adobe Photoshop Document Data Block	37724	R/W
InteroperabilityIFDOffset	40965	R/W
DNGVersion	50706	R/W	DNG 1.0 tags
DNGBackwardVersion	50707	R/W
UniqueCameraModel	50708	R/W
LocalizedCameraModel	50709	R/W
CFAPlaneColor	50710	R/W
CFALayout	50711	R/W
LinearizationTable	50712	R/W
BlackLevelRepeatDim	50713	R/W
BlackLevel	50714	R/W
BlackLevelDeltaH	50715	R/W
BlackLevelDeltaV	50716	R/W
WhiteLevel	50717	R/W
DefaultScale	50718	R/W
DefaultCropOrigin	50719	R/W
DefaultCropSize	50720	R/W
ColorMatrix1	50721	R/W
ColorMatrix2	50722	R/W
CameraCalibration1	50723	R/W
CameraCalibration2	50724	R/W
ReductionMatrix1	50725	R/W
ReductionMatrix2	50726	R/W
AnalogBalance	50727	R/W
AsShotNeutral	50728	R/W
AsShotWhiteXY	50729	R/W
BaselineExposure	50730	R/W
BaselineNoise	50731	R/W
BaselineSharpness	50732	R/W
BayerGreenSplit	50733	R/W
LinearResponseLimit	50734	R/W
CameraSerialNumber	50735	R/W
LensInfo	50736	R/W
ChromaBlurRadius	50737	R/W
AntiAliasStrength	50738	R/W
ShadowScale	50739	R/W
DNGPrivateData	50740	R/W
MakerNoteSafety	50741	R/W
CalibrationIlluminant1	50778	R/W
CalibrationIlluminant2	50779	R/W
BestQualityScale	50780	R/W
RawDataUniqueID	50781	R/W
OriginalRawFileName	50827	R/W
OriginalRawFileData	50828	R/W
ActiveArea	50829	R/W
MaskedAreas	50830	R/W
AsShotICCProfile	50831	R/W
AsShotPreProfileMatrix	50832	R/W
CurrentICCProfile	50833	R/W
CurrentPreProfileMatrix	50834	R/W
PerSample	65563	R/W	(only internal pseudo tag)
Indexed	346	R/W	TIFF/FX tags
GlobalParametersIFD	400	R/W
ProfileType	401	R/W
FaxProfile	402	R/W
CodingMethods	403	R/W
VersionYear	404	R/W
ModeNumber	405	R/W
Decode	433	R/W
ImageBaseColor	434	R/W
T82Options	435	R/W
StripRowCounts	559	R/W	part of RFC 2301 for fax
ImageLayer	34732	R/W

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".

Tag RichTIFFIPTC (33723) is defined wrongly in TIFF/EP definition as "LONG or ASCII". libtiff defines it as "UNDEFINED or BYTE".

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 and TIFF File Format Specification.

Codecs / Compression

The following tags are used by codecs.

Codec / Compression Tags used by libtiff

Tag Name	Value	R/W<	Library's Use (Comments)
Predictor	317	R/W	LZW codec
JPEGTables	347	R/W	JPEG
JpegInterchangeFormat	513	R/W	OJPEG
JpegInterchangeFormatLength	514	R/W	OJPEG
JpegQTables	519	R/W	OJPEG
JpegDcTables	520	R/W	OJPEG
JpegAcTables	521	R/W	OJPEG
JpegProc	512	R/W	OJPEG
JpegRestartInterval	515	R/W	OJPEG
BadFaxLines	326	R/W	CCITT / fax
CleanFaxData	327	R/W	CCITT / fax
ConsecutiveBadFaxLines	328	R/W	CCITT / fax
Group3Options	292	R/W	CCITT / fax
Group4Options	293	R/W	CCITT / fax
LercParameters	50674	R/W	LERC

Note: This codec-specific tags and the library does not recognize them except when the Compression tag has been previously set to the relevant compression scheme.

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

EXIF / GPS Custom IFDs

In addition to the standard TIFF tags, libtiff has predefined IFDs (image file directories) with the tags for EXIF (version 2.32) and EXIF-GPS as custom directories. For reading / writing of this IFDs refer to TIFFCustomDirectory.

EXIF Custom Tags

EXIF 2.32 Tags used by libtiff

Tag Name	Value	R/W<	Library's Use (Comments)
ExposureTime	33434	R/W
FNumber	33437	R/W
ExposureProgram	34850	R/W
SpectralSensitivity	34852	R/W
ISOSpeedRatings	34855	R/W	After EXIF 2.2.1 ISOSpeedRatings is named PhotographicSensitivity. In addition, while "Count=Any", only 1 count should be used.
OptoelectricConversionFactor	34856	R/W
SensitivityType	34864	R/W
StandardOutputSensitivity	34865	R/W
RecommendedExposureIndex	34866	R/W
ISOSpeed	34867	R/W
ISOSpeedLatitudeyyy	34868	R/W
ISOSpeedLatitudezzz	34869	R/W
ExifVersion	36864	R/W
DateTimeOriginal	36867	R/W
DateTimeDigitized	36868	R/W
OffsetTime	36880	R/W
OffsetTimeOriginal	36881	R/W
OffsetTimeDigitized	36882	R/W
ComponentsConfiguration	37121	R/W
CompressedBitsPerPixel	37122	R/W
ShutterSpeedValue	37377	R/W
ApertureValue	37378	R/W
BrightnessValue	37379	R/W
ExposureBiasValue	37380	R/W
MaxApertureValue	37381	R/W
SubjectDistance	37382	R/W
MeteringMode	37383	R/W
LightSource	37384	R/W
Flash	37385	R/W
FocalLength	37386	R/W
SubjectArea	37396	R/W
MakerNote	37500	R/W
UserComment	37510	R/W
SubSecTime	37520	R/W
SubSecTimeOriginal	37521	R/W
SubSecTimeDigitized	37522	R/W
Temperature	37888	R/W
Humidity	37889	R/W
Pressure	37890	R/W
WaterDepth	37891	R/W
Acceleration	37892	R/W
CameraElevationAngle	37893	R/W
FlashpixVersion	40960	R/W
ColorSpace	40961	R/W
PixelXDimension	40962	R/W
PixelYDimension	40963	R/W
RelatedSoundFile	40964	R/W
FlashEnergy	41483	R/W
SpatialFrequencyResponse	41484	R/W
FocalPlaneXResolution	41486	R/W
FocalPlaneYResolution	41487	R/W
FocalPlaneResolutionUnit	41488	R/W
SubjectLocation	41492	R/W
ExposureIndex	41493	R/W
SensingMethod	41495	R/W
FileSource	41728	R/W
SceneType	41729	R/W
CFAPattern	41730	R/W
CustomRendered	41985	R/W
ExposureMode	41986	R/W
WhiteBalance	41987	R/W
DigitalZoomRatio	41988	R/W
FocalLengthIn35mmFilm	41989	R/W
SceneCaptureType	41990	R/W
GainControl	41991	R/W
Contrast	41992	R/W
Saturation	41993	R/W
Sharpness	41994	R/W
DeviceSettingDescription	41995	R/W
SubjectDistanceRange	41996	R/W
ImageUniqueID	42016	R/W
CameraOwnerName	42032	R/W
BodySerialNumber	42033	R/W
LensSpecification	42034	R/W
LensMake	42035	R/W
LensModel	42036	R/W
LensSerialNumber	42037	R/W
Gamma	42240	R/W
CompositeImage	42080	R/W
SourceImageNumberOfCompositeImage	42081	R/W
SourceExposureTimesOfCompositeImage	42082	R/W

GPS Custom Tags

GPS 2.32 Tags used by libtiff

Tag Name	Value	R/W<	Library's Use (Comments)
VersionID	0	R/W
LatitudeRef	1	R/W
Latitude	2	R/W
LongitudeRef	3	R/W
Longitude	4	R/W
AltitudeRef	5	R/W
Altitude	6	R/W
TimeStamp	7	R/W
Satellites	8	R/W
Status	9	R/W
MeasureMode	10	R/W
DOP	11	R/W
SpeedRef	12	R/W
Speed	13	R/W
TrackRef	14	R/W
Track	15	R/W
ImgDirectionRef	16	R/W
ImgDirection	17	R/W
MapDatum	18	R/W
DestLatitudeRef	19	R/W
DestLatitude	20	R/W
DestLongitudeRef	21	R/W
DestLongitude	22	R/W
DestBearingRef	23	R/W
DestBearing	24	R/W
DestDistanceRef	25	R/W
DestDistance	26	R/W
ProcessingMethod	27	R/W
AreaInformation	28	R/W
DateStamp	29	R/W
Differential	30	R/W
HorizontalPositioningError	31	R/W