2005.09.08 19:13 "[Tiff] creating JPEG file", by Philip Watkinson

2005.09.09 09:31 "Re: [Tiff] 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/
Download your free TIFF tag viewer for windows here:
http://www.awaresystems.be/imaging/tiff/astifftagviewer.html