Re: Advice for compressing TIFFs

cubilcle281 wrote:
Your followup post notwithstanding, I tried ZIP files using
powerarchiver, and saw a saving of only 3-5%. The other issue is that
the zip files did not like olding 5GB of data (at least, using
PowerArchiver).

I could always try individual zip files, but I need somewhere in the
region of 20% reduction in size to make things fit.

Is there a version of TIFF that supports 12-bit files, since that is
what the LS-2000 is actually producing?

There is not a 1:1 relationship between the number of bits the scanner sensor produces and the number of bits in a TIFF file. The scanner sensor is linear; the data in image files is not. That is how 8-bit JPEGS (for example) manage to cover a theoretical contrast range of 1:200000 - far more than any screen or paper can reproduce. A 12-bit scanner will manage a maximum contrast range of 1:4000 (which is still enough).

8-bit images are not so great if you try to make large changes to the brightness or contrast. As long as you get the exposure about right when doing the original scan, 8-bit images are fine. I have settled on using JPEGs with the quality set to "high".

But don't take my word for it - make a few test prints to convince yourself of the quality you need. The trial version of Picture Window Pro will let you play with 16-bit files for 30 days.

-Tim
.