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AndyDe
7th of June 2003 (Sat), 03:07
I'm now taking my 10D photo's in RAW format & editing them in 16bit mode in photoshop & saving any that I want to keep in TIF format.
Does it make any difference what type of compression is used ?
I assume that if I change it to 8 bit to apply any filters etc then there's not much point in converting back to 16 bit...am I correct ?
I've noticed that the saved TIF is larger than 36 meg, does anyone know why this is ?
I suspect these have been asked before, I have had a quick trawl back, if they have then I apologise.
Thanks
Andy
chris maddock
7th of June 2003 (Sat), 07:48
AndyDe wrote:
I'm now taking my 10D photo's in RAW format & editing them in 16bit mode in photoshop & saving any that I want to keep in TIF format.
Does it make any difference what type of compression is used ?

Not if they are TIFFS - as far as I know all TIFF compresion is lossless.

I assume that if I change it to 8 bit to apply any filters etc then there's not much point in converting back to 16 bit...am I correct ?

That's my belief - often I don't even bother starting off in 16-bit, unless a particular image is proving troublesome to get as I want in 8-bit.

I've noticed that the saved TIF is larger than 36 meg, does anyone know why this is ?


I suspect you're using adjustment layers, and those are being saved as well.

KRs
Chris
daveh
7th of June 2003 (Sat), 10:21
AndyDe wrote:
I've noticed that the saved TIF is larger than 36 meg, does anyone know why this is ?


How much larger? Mine are about 36.1MB. Slightly less than twice the size of my 8bit tiffs.
AndyDe
7th of June 2003 (Sat), 10:28
daveh wrote:
How much larger? Mine are about 36.1MB. Slightly less than twice the size of my 8bit tiffs.

Around 40 meg, they stay around that size as well if they're converted from 16 to 8 bit ?
john_houghton
7th of June 2003 (Sat), 11:00
AndyDe wrote:
Does it make any difference what type of compression is used ?

The problem with LZW compression is that it is a patented technology owned by Unisys. Many programs cannot open tiff files with LZW compression because the appropriate licences have not been acquired. As it happens, the patents are due to expire this month as far as the US is concerned, and later for the rest of the world, so the situation may be about to change.

John