[PRCo] Re: Pittsburgh slides

[Derrick J Brashear]

Well, this is wildly off-topic. I shouldn't even send it, but I haven't
eaten in like 12 hours, so my judgement has gone south.

On Fri, 9 Apr 2004, John F Bromley wrote:

> When I want an 8x10 they can be expanded to larger sizes, time and again if
> need be - TIFF files do this without loss, unlike JPEGS.

Technically speaking if you throw away resolution it's gone, and that's
orthogonal to JPEG compression. Lossy compression, like JPEG, takes
advantage of human perception to throw away information which you can't
get back, but you can also reduce the resolution of a JPEG, just like a
TIFF, and the information is gone, never to come back.

I use zip (a.k.a. deflate) compression on TIFFs, which is lossless.
There's also lzw, the patents expired in June 2003 in the U.S. but are
valid in Canada for 3 more months. And yes, you can have a TIFF with JPEG
compression, and it's lossy, just like it is for a real JPEG.

If you want a lossless compression which does a better job of making small
files, you want C44 compression, which DjVu will do... but there are only
crude tools to do it.

> When printing I use 300 dpi - anything more is complete and total overkill
> and gets you nothing except losing time while it loads.  Trust me I've done
> side by side comparisons and I think the 300dpi's are better, since they're
> not trying to slather ink into the same space and put too much down.  Fast,
> great looking.

This however I'm not about to argue with.

> Save yourself some time and space.

I prefer to scan and keep the high resolution, and lower it when I print.