2015.10.08 14:01 "Re: [Tiff] TIFF Specification Allowance for Multi-Page vs. Reduced Res 2nd IFD", by Doug Peterson
Friends of the TIFF info mailing list.
I'm writing to wrap up a thread I started in 2013.
Our software's processing engine for TIFFs was including a "reduced-resolution image" directory using the SubFileType after the main image directory. While technically we were not doing it "wrong" Joris helped us understand that the approach was dated and that readers had to explicitly support it leading to significant issues in readers that did not
explicitly support it.
In 2014 we added an option to simply not include the second IFD and wrote a simple ImageMagik powered droplet to remove the second IFD to use on previously processed files as needed.
It was a problem that only effected a very small % of our users, but we would not have been able to address it without the help of the nice people of this mailing list. I was reminded of this help when a client running an older version of the software ran into this problem and I had to delve back into this thread to remind myself of the particulars and realized I never wrote a conclusion to the thread.
So thanks again for volunteering your help! If anyone ever needs help with medium format digital still camera systems or wedding photography I'd be glad to reciprocate.
On Fri, Jun 14, 2013 at 5:06 PM, Joris Van Damme (AWare Systems) < firstname.lastname@example.org> wrote:
> 2013/6/14 Frank Warmerdam <email@example.com>:
> > I have run tiffinfo on the file and amoung the tags I see:
> > SubIFD Offsets: 79455156
> > So this seems to be a subifd pyramid level. It strickes me as slightly
> > that there is only one overview level and it is just a 2x2 downsampling
> > it is a pyramid level.
> I'm seeing something different, still. I'll try and copy/paste, hope
> you're viewing this as a HTML mail.
> In the main top-level linked list, I'm seeing a single IFD...
> <http://www.awaresystems.be/imaging/tiff/tifftags/imagelength.html> Short1
> <http://www.awaresystems.be/imaging/tiff/tifftags/bitspersample.html>Short > 38, 8, 8 Compression
> <http://www.awaresystems.be/imaging/tiff/tifftags/compression.html>Short1 > LZWPhotometricInterpretation
> <http://www.awaresystems.be/imaging/tiff/tifftags/photometricinterpretation.html> > Short1RGBMake <http://www.awaresystems.be/imaging/tiff/tifftags/make.html>
> Ascii10"Phase One " Model
> <http://www.awaresystems.be/imaging/tiff/tifftags/stripoffsets.html> Long > 93932382, 103176, 170464, 237880, 304740, 373346, 441212, 510264, 578644,
> 648884, 716534, 785266,...Orientation
> <http://www.awaresystems.be/imaging/tiff/tifftags/orientation.html> Short1
> Short 13RowsPerStrip
> <http://www.awaresystems.be/imaging/tiff/tifftags/stripbytecounts.html> > Long93970794, 67287, 67416, 66859, 68605, 67866, 69051, 68379, 70240,
> 67650, 68731, 70254, 71849, 72085,...XResolution
> Rational1300 PlanarConfiguration
> <http://www.awaresystems.be/imaging/tiff/tifftags/software.html>Ascii32"Adobe > Photoshop CS6 (Macintosh) " DateTime
> <http://www.awaresystems.be/imaging/tiff/tifftags/datetime.html>Ascii20"2013:06:14 > 12:14:08 " Prepn