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1994.01.25 04:02 "Adobe Private TIFF Tag", by Gordon Bennett
1994.01.25 17:59 "Re: Adobe Private TIFF Tag", by Niles Ritter

1994.01.25 17:59 "Re: Adobe Private TIFF Tag", by Niles Ritter

Gordon Bennett writes,

>  Does anyone know what tag 34377 is?  I've encountered it in TIFF files built
>  by Adobe Photoshop, but even though it's a private tag, Adobe says they don't
>  know what it is and referred me to Aldus.

I just created an RGB TIFF file from scratch, using Adobe Photoshop,
and running tiffdump on it I got:

SubFileType (254) LONG (4) 1<0>
ImageWidth (256) SHORT (3) 1<0>
ImageLength (257) SHORT (3) 1<0>
BitsPerSample (258) SHORT (3) 3<8 8 8>
Compression (259) SHORT (3) 1<0>
Photometric (262) SHORT (3) 1<0>
StripOffsets (273) LONG (4) 1<604>
SamplesPerPixel (277) SHORT (3) 1<0>
RowsPerStrip (278) SHORT (3) 1<0>
StripByteCounts (279) LONG (4) 1<196608>
XResolution (282) RATIONAL (5) 1<72>
YResolution (283) RATIONAL (5) 1<72>
PlanarConfig (284) SHORT (3) 1<0>
ResolutionUnit (296) SHORT (3) 1<0>
34377 (0x8649) BYTE (1) 
    388<56 66 73 77 3 233 0 0 0 0 0 120 0 3 0 0 0 72 0 72 0
    0 0 0 2 218 2 40 255 225 255 226 2 249 2 70 3 71 5
    40 3 252 0 2 0 0 0 72 0 72 0 0 0 0 2 218 2 40 0 1
    0 0 0 100 0 0 0 1 0 1 1 1 0 0 0 1 39 15 0 1 0 1 0
    0 0 0 0 0 0 0 0 0 0 0 0 2 0 25 1 144 0 0 0 0 0 64 0
    0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
    56 66 73 77 3 237 0 0 0 0 0 16 0 72 0 0 0 1 0 1 0
    72 0 0 0 1 0 1 56 66 73 77 3 243 0 0 0 0 0 7 0 0 0
    0 0 0 0 0 56 66 73 77 3 245 0 0 0 0 0 72 0 47 102
    102 0 1 0 108 102 102 0 6 0 0 0 0 0 0 0 47 102 102
    0 1 0 161 153 154 0 6 0 0 0 0 0 0 0 50 0 0 0 1 0 90
    0 0 0 6 0 0 0 0 0 0 0 53 0 0 0 1 0 45 0 0 0 6 0 0 0
    0 0 0 56 66 73 77 3 248 0 0 0 0 0 112 0 0
    255 255 255 255 255 255 255 255 255 255 255 255 255
    255 255 255 255 255 255 255 255 255 3   232 0   0   0 0 255
    255 255 255 255 255 255 255 255 255 255 255 255 255 255
    255 255 255 255 255 255 255 3   232 0   0   0   0   255 255 255 255
    255 255 255 255 255 255 255 255 255 255 255 255 255 255
    255 255 255 255 3   232 0   0   0   0   255 255 255 255 255 255 255
    255 255 255 255 255 255 255 255 255 255 255 255 255 255 255 3 232 0 0>

Some parts look like resolution values (72 0 72 0), and other parts look
like lookup tables or perhaps small bitmaps for a mask. In either case,
since this file was created by Adobe, somebody over there *should*
know what the thing is for. Looks like a private structure of some
sort. Ask to talk to one of their technical guys, not the artists.

BTW, every color TIFF image I created was given the same tag and value;
changing the "preferences" of the program, changing the saturation/
levels/brightness/pagesetup/size etc. of the image made no difference.
The only time I got a different count/value of that tag was when I
converted the color tiff to grayscale. An interesting pattern occurs
if you organize the last run of 255's by rows of 28 bytes each:

0   0   255 255 255 255 255 255 ... 255 255 255 255 255 3  232 0   0   
0   0   255 255 255 255 255 255 ... 255 255 255 255 255 3  232 0   0   
0   0   255 255 255 255 255 255 ... 255 255 255 255 255 3  232 0   0   
0   0   255 255 255 255 255 255 ... 255 255 255 255 255 3  232 0   0   

I have no idea what that means; I'm not that good a numerologist:-)

  -niles.