[Image-SIG] PIL not loading some TIFF files?
Green Bryan - bgreen
Bryan.Green at acxiom.com
Wed Nov 5 01:11:50 CET 2008
They are required per the TIFF 6.0 baseline standard. Here is a link (and I pasted the relevant text from p.64):
http://www.alternatiff.com/resources/TIFF6.pdf
Required Fields for RGB Images
These are the required fields for RGB images (in numerical order):
TagName Decimal Hex Type Value
ImageWidth 256 100 SHORT or LONG
ImageLength 257 101 SHORT or LONG
BitsPerSample 258 102 SHORT 8,8,8
Compression 259 103 SHORT 1 or 32773
PhotometricInterpretation 262 106 SHORT 2
StripOffsets 273 111 SHORT or LONG
SamplesPerPixel 277 115 SHORT 3 or more
RowsPerStrip 278 116 SHORT or LONG
StripByteCounts 279 117 LONG or SHORT
XResolution 282 11A RATIONAL
YResolution 283 11B RATIONAL
ResolutionUnit 296 128 SHORT 1, 2 or 3
24
TIFF 6.0 Specification Final—June 3, 1992
The BitsPerSample values listed above apply only to the main image data. If
ExtraSamples are present, the appropriate BitsPerSample values for those
samples must also be included.
Baseline TIFF RGB images were called TIFF Class R images in earlier versions
of the TIFF specification.
-----Original Message-----
From: B. Bogart [mailto:ben at ekran.org]
Sent: Tue 11/4/2008 6:06 PM
To: Green Bryan - bgreen
Cc: image-sig at python.org
Subject: Re: [Image-SIG] PIL not loading some TIFF files?
Thanks for the details.
I've passed this info onto the pd/Gem developers so they can add these
tags to all tifs written by the software.
Are these tags required as part of the TIFF spec? Or are they just best
practise?
Thanks again,
B. Bogart
Green Bryan - bgreen wrote:
> It appears that the problem has to do with the following tags not being
> set in the image. I set these with the tiffset program and PIL then
> loaded the image without any trouble. I do not know how to set these
> tags in PIL. Maybe someone has a suggestion? Also, if you open the
> file in GIMP and save the problem is fixed. I understand this is not a
> solution for you-- just making note.
>
> Most viewers follow fairly closely to the tif spec (they also try and do
> the "right thing" for non-standard software)-- PIL is not so forgiving.
> If needed you could write a script to fix the tags on the fly using the
> command line tiffset program. It is fast.
>
> XResolution (282) RATIONAL (5) 1<72>
> YResolution (283) RATIONAL (5) 1<72>
> ResolutionUnit (296) SHORT (3) 1<2>
>
>
> -----Original Message-----
> From: image-sig-bounces+bryan.green=acxiom.com at python.org
> [mailto:image-sig-bounces+bryan.green=acxiom.com at python.org] On Behalf
> Of Green Bryan - bgreen
> Sent: Tuesday, November 04, 2008 4:52 PM
> To: B. Bogart; image-sig at python.org
> Subject: Re: [Image-SIG] PIL not loading some TIFF files?
>
> There are some differences between the two. Mask.tif claims to have
> been created by the GIMP and has a bps of 3 8-bit values.
> Store-0000.tif has a software type of PD/GEM and a bps of 4 8-bit
> values.
>
>
> c:\store-00000.tif:
> Magic: 0x4949 <little-endian> Version: 0x2a
> Directory 0: offset 1228808 (0x12c008) next 0 (0)
> ImageWidth (256) SHORT (3) 1<640>
> ImageLength (257) SHORT (3) 1<480>
> BitsPerSample (258) SHORT (3) 4<8 8 8 8>
> Compression (259) SHORT (3) 1<1>
> Photometric (262) SHORT (3) 1<2>
> StripOffsets (273) LONG (4) 1<8>
> SamplesPerPixel (277) SHORT (3) 1<4>
> StripByteCounts (279) LONG (4) 1<1228800>
> PlanarConfig (284) SHORT (3) 1<1>
> Software (305) ASCII (2) 7<PD/GEM\0>
>
> c:\mask.tif:
> Magic: 0x4949 <little-endian> Version: 0x2a
> Directory 0: offset 921608 (0xe1008) next 0 (0)
> SubFileType (254) LONG (4) 1<0>
> ImageWidth (256) SHORT (3) 1<640>
> ImageLength (257) SHORT (3) 1<480>
> BitsPerSample (258) SHORT (3) 3<8 8 8>
> Compression (259) SHORT (3) 1<1>
> Photometric (262) SHORT (3) 1<2>
> DocumentName (269) ASCII (2) 66</home/bbogart/Projects/i ...>
> ImageDescription (270) ASCII (2) 22<Created with The GIMP\0>
> StripOffsets (273) LONG (4) 8<8 122888 245768 368648 491528 614408
> 737288 860168>
> Orientation (274) SHORT (3) 1<1>
> SamplesPerPixel (277) SHORT (3) 1<3>
> RowsPerStrip (278) SHORT (3) 1<64>
> StripByteCounts (279) LONG (4) 8<122880 122880 122880 122880 122880
> 122880 122880 61440>
> XResolution (282) RATIONAL (5) 1<72>
> YResolution (283) RATIONAL (5) 1<72>
> PlanarConfig (284) SHORT (3) 1<1>
> ResolutionUnit (296) SHORT (3) 1<2>
>
> -----Original Message-----
> From: image-sig-bounces+bryan.green=acxiom.com at python.org
> [mailto:image-sig-bounces+bryan.green=acxiom.com at python.org] On Behalf
> Of B. Bogart
> Sent: Tuesday, November 04, 2008 4:14 PM
> To: image-sig at python.org
> Subject: [Image-SIG] PIL not loading some TIFF files?
>
> Hello all,
>
> I'm unable to get PIL (Image.open) to load certain TIFF files generated
> by another application (using libtiff).
>
> According to imageMagick the files are the same type:
>
> mask.tif TIFF 640x480 640x480+0+0 DirectClass 8-bit 900.383kb
> store-00000.tif[1] TIFF 640x480 640x480+0+0 DirectClass 8-bit 1.17202mb
>
> mask.tif loads fine:
>
>>>> image = Image.open("mask.tif")
>>>>
>
> but store-00000.tif fails:
>
>>>> image = Image.open("store-00000.tif")
> Traceback (most recent call last):
> File "<stdin>", line 1, in <module>
> File "/usr/lib/python2.5/site-packages/PIL/Image.py", line 1917, in
> open
> raise IOError("cannot identify image file")
> IOError: cannot identify image file
>
> I'm running PIL 1.1.6-3 in python 2.5 on ubuntu hardy.
>
> You can grab these two files from:
>
> http://www.ekran.org/ben/tmp/mask.tif
> http://www.ekran.org/ben/tmp/store-00000.tif
>
> This is a problem because it is files created by this very application I
> need to be able to read with PIL. Converting them is not practical
> because there will be at least 900 images and processing time is an
> issue.
>
> Thanks,
> B. Bogart
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