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July 2007
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2007.07.05 02:41 "Re: BigTIFF extension", by Joris Van Damme
Stephen, Stephen Carlsen wrote: > "Because, for the first time in the 21 year history of TIFF, the > structure itself has changed, and, accordingly, the 'version number' > has changed from 42 to 43. (The 'version number' has, of course, been > 42 since the very beginning of TIFF.) This breaks all existing TIFF > readers." The exact same thing applies to the coming of tiles in TIFF. It wasn't the structure itself that had changed at that time, but it was some of the extremely vital tags, which resulted in the same. It broke all existing TIFF readers. Your reasoning would have applied back then, too, and we'd be forced to use 'tf3' as an extension right now because 'tf2' would have been taken for tiled TIFF. No, actually, we would be forced to use 'tf3' for striped BigTIFF and 'tf4' for tiled BigTIFF, probably. Put things to this extreme, and you can end up encoding all information in the extension. That's not a good thing to do. Put the exact information where it belongs, not more and not less, and don't code anything twice. The extension is for marking the file format, and that's TIFF in both ClassicTIFF and BigTIFF version. The version number, in turn, marks the version. That's just good, and truthfull information encoding management. Best regards, 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