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2005.09.09 09:31 "Re: creating JPEG file", by Joris Van Damme
Bob,
> I just verified that GraphicsMagick 1.2 is able to read and write a
> TIFF file conforming to your specification using libtiff 3.7.3. A
> sample is attached.
I cannot make sense of the image.
File "planar-jpeg.tiff"
Byte order: Motorola
Format: Classic TIFF
IFD Tree
Single page at offset 15996
Single page
Offset: 15996
Next IFD: 0
ImageWidth (1 SHORT): 120
ImageLength (1 SHORT): 95
BitsPerSample (4 SHORT): 8, 8, 8, 8
Compression (1 SHORT): JPEG ('new-style' JPEG)
PhotometricInterpretation (1 SHORT): Seperated, usually CMYK
FillOrder (1 SHORT): lower column values in the higher-order bits
DocumentName (17 ASCII): "planar-jpeg.tiff"
Orientation (1 SHORT): 0th row is top, 0th column is left-hand side
SamplesPerPixel (1 SHORT): 4
PlanarConfiguration (1 SHORT): Planar format
Software (65 ASCII): "GraphicsMagick 1.2 unreleased Q16
http://www....
WhitePoint (2 RATIONAL): 0,312700003385544, 0,328999996185303
PrimaryChromaticities (6 RATIONAL): 0,639999985694885,...
TileWidth (1 SHORT): 16
TileLength (1 SHORT): 16
TileOffsets (192 LONG): 8, 249, 548, 899, 1171, 1597, 1921, 2190,...
TileByteCounts (192 LONG): 58, 73, 85, 66, 105, 80, 65, 68, 62,
87,...
InkSet (1 SHORT): CMYK
SampleFormat (4 SHORT): unsigned integer data, unsigned integer data,
unsigned integer data, unsigned integer data
JPEGTables (289 UNDEFINED): 255, 216, 255, 219, 0, 67, 0, 8, 6, 6,...
YCbCrSubSampling (2 SHORT): 2, 2
I've seen YCbCrSubSampling used with YCbCr, of course, and with ITULAB,
and, logically extending it, it could also be used with any other color
space that has a single lightness/brightness channel followed by chroma
channels. But it is not clear to me how it should apply to CMYK. I don't
think this combination makes sense.
Joris Van Damme
info@awaresystems.be
http://www.awaresystems.be/
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