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TIFF and LibTiff Mail List Archive

Thread

2005.04.28 13:40 "[Tiff] Delphi 7, TIFF G3/4, Multipage", by Matthias Lach
2005.04.29 16:09 "Re: [Tiff] Delphi 7, TIFF G3/4, Multipage", by Joris
2005.05.02 16:12 "RE: [Tiff] Color TIFF/JPEG compression questions", by Frank, Jason
2005.05.02 13:44 "RE: [Tiff] Color TIFF/JPEG compression questions", by Grissom, Ed
2005.05.02 14:16 "Re: [Tiff] Color TIFF/JPEG compression questions", by Joris
2005.05.02 16:29 "RE: [Tiff] Color TIFF/JPEG compression questions", by Frank, Jason
2005.05.02 17:55 "Re: [Tiff] Color TIFF/JPEG compression questions", by Joris
2005.05.02 18:17 "RE: [Tiff] Color TIFF/JPEG compression questions", by Frank, Jason

2005.05.02 14:16 "Re: [Tiff] Color TIFF/JPEG compression questions", by Joris

then the
points I made.

> TiffTechNote 2 requires that if the underlying JPEG compression > uses YCbCr

Note that Photoshop apparently is able to save CMYK jpeg-in-tiff.

Tagdump of one such image generated with Photoshop:

SubFileType (1 Long): Zero
ImageWidth (1 Short): 3050
ImageLength (1 Short): 2035
BitsPerSample (4 Short): 8, 8, 8, 8
Compression (1 Short): JPEG Technote #2
Photometric (1 Short): Seperated

StripOffsets (407 Long): 26480, 50636, 74784, 99608, 124780, 150312,... SamplesPerPixel (1 Short): 4

RowsPerStrip (1 Short): 5

StripByteCounts (407 Long): 24156, 24148, 24823, 25172, 25532, 25662,... XResolution (1 Rational): 305

YResolution (1 Rational): 305
PlanarConfig (1 Short): Contig
ResolutionUnit (1 Short): Inch
Software (20 ASCII): Adobe Photoshop 7.0
DateTime (20 ASCII): 2004:08:29 15:13:38
DotRange (2 Byte): 0, 255
JpegTables (285 Undefined):

700 (4649 Byte): 60, 63, 120, 112, 97, 99, 107, 101, 116, 32,... Photoshop (17958 Byte): 56, 66, 73, 77, 4, 37, 0, 0, 0, 0, 0, 16, 0,... 34665 (1 Long): 10661832

Upon examination of the first strip data, I see an APP14 marker, and 4 channels

specified in both the SOF0 and SOS marker. The 'color transform' byte in the

Adobe-style APP14 marker equals 0, which I take to mean that actual true CMYK is

encoded in the jpeg data, without additional tranformation.

 Joris Van Damme
 info@awaresystems.be
 http://www.awaresystems.be/
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