2004.04.21 07:30 "Re: [Tiff] Large TIFF files", by Rob van den Tillaart

Professional Photoshop users needed 64 bit TIFF now. Some high-end print users needed it about 3 years ago.

How does Photoshop solves this need today?

I would break the possibilities down farther:

1. break with existing and keep as much compatibility as possible
2. break with existing and keep only the good ideas, but not value compatibility (meaning that tag values will change, and we can clean out some cruft)

Note that cruft has the nasty attribute of allways appearing again in some way :)

Some people have suggested that ASCII based tags would make debugging far easier - and if we're going to 64 bit values we can use 8 byte tags as well.

tag: 'ICCProfl', 'Compress', etc.

I like this idea but the BTIFF/BIF format is for computers first, a dump tool can make it human readable. Doubt if 8 chars will be enough remember the 8.3 filename style.

Taking this idea to the extreme we could also write the values in ASCII. Reminds me that some time ago I was thinking about an XML version of TIFF. Readability would be improved (although XML considered readable??). We could use all kinds of XML tooling developed during the internet hype. The filesize would however expand at least with a factor 2, processing it takes extra overhead. Some time ago I read about an comparison between ASN-1 coding (strict binary) and XML (strict ascii) and the differences in performance went up to a factor 6. (in an IEEE magazine).

regards,
rob tillaart