On Wed, Feb 24, 2010 at 3:50 PM, Zoran Zorkic <zomba@...
> >images. If you need >2GB you can still use TIFF up to 4GB (looking forward
> >to BigTIFF support someday), or you can just use PSB and not worry about
> >practical limits. Since TIFF supports several useful compression options
> >varying bit depths, a 4GB TIFF can well be quite larger than it would
> >suggest if you were using only uncompressed data.
> Ah, therein I think lies the problem. It's not 4gb compressed, but 4gb
> UNCOPRESSED limit.
> All TIFFs under 4gb uncopressed opened OK, but compressed no, even though
> the filesize is below 4gb.
Nope, the limit is on the final compressed TIFF, because the limit has to do
with the internal TIFF tag addresses, which are calculated based on the
location of the stored (compressed) samples, which are 32 bit unsigned. It
would be easier if the limit were on the uncompressed - at least then you'd
always know if a file was going to be too big to save (it's impossible to
know if your 10GB uncompressed image will fit in a 4GB compressed TIFF until
you try - and sometimes fail!
> >Of course Photoshop is still not ideal for extremely large work, but it
> Yup, but it's indispensible. I'll probaly end up using both Nip2 and
> I'll just crop the image into the biggest sensible parts and use that in
> Photoshop, merge back later.
Yes, if you want the best of both you might using nip2 to merge tiles
together up to a size you know can be opened (as a TIFF) in Photoshop. Then
open those super-tiles in Photoshop and merge... that way you'd avoid the
overhead of lots of small file operations which Photoshop isn't the most
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