On Sat, Jan 22, 2011 at 11:15 AM, Ralph Zerbonia <ra...@universecentral.com> wrote: > My question is whether or not anyone knows of any image disadvantages, is > there anything about LZW that would allow a loss of any visual fidelity?
LZW is indeed lossless. I just did a quick test[0] to be sure that GIMP's implementation is lossless and it turned out OK[1]. PNG is a lossless format as well, and may give a slightly smaller file size than TIFF. Chris [0] I did the following in GIMP 2.6.10: - Open an uncompressed TIFF file - Save a copy with LZW - Close all files - Open original - Open As Layers LZW copy - Change LZW layer mode to "Difference" - Move the cursor about in the image while looking in the 'Pointer' dialog - All RGB values are 0% (black) throughout the image (could also flatten the image at this point and use levels or curves to verify that there are no anomalies) [1] In an older version of Photoshop (5? 6?) I did the above and came out with a very slight "shift" or "loss". It could have been a mistake on my part, but at the time we figured it was a bug in Adobe's LZW handling. I can't reproduce this any more in Photoshop - so whether or not it was pilot error or a bug, it's no longer relevant - except it's the reason I remember the above procedure ;) _______________________________________________ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
