Mendel Leisk , Aug 28, 2004; 11:00 p.m.
Are you asking about files with extension ".tif". LZW is a compression commonly associated with tiffs. If you are using Vuescan, you can specify lzw compression when outputting tiffs, either the finished gamma tiffs, or "Vuescan Raw File" tiffs.
In my case, I output Vuescan raw files (tiff format) that range between 35~45 megs, with lzw compression. Without lzw, they would be around 55 megs. In the course of working these files in Photoshop, the compression ratio erodes, with each re-save. Sometimes, they end up bigger than uncompressed!
After completion of PS editing, I'll use these to output a fresh raw file, within Vuescan, getting the compression ratio back, and then delete the PS edited version (after checking the new ones are ok).
I don't think zip would compress any better than lzw. I've tried it, and it is ponderously slow. As to Zip integrity, I believe it is safe. But lzw has two advantages:
1. The file is still a tiff, accessable as is, albeit a little slower to open.
2. If you do a multiple file zip, you are making it more difficult to access/use your files. And, if the zip were to somehow become corrupted, you have all your eggs in one basket.