tedster - 9:44 pm on Mar 24, 2001 (gmt 0)

I wonder about using PNG as a benchmark, since it's already a compressed file. I make my comparisons starting with a PSD file. That may be why we see differences.

At any rate, the file size savings are not huge, 5% or so on the same jpg settings. But I often can push the compression further without visible artifacting after the L-a-b blur, so that gives additional savings.

I read this technique (and quite a few other uses for L-a-b) a few years ago in a column in PEI magazine by Dan Margulis. He expanded his colmuns into a great book called "Makeready". It's out of print now, unfortunately, but a grat resource. Margulis is quite the PhotoShop guru, giving very expensive seminars these days - mostly focused on print applications.