I am replying to the list as well, so that this
  is archived!  Thanks much for the prompt
  reply. I won't have time right away to try this
  in detail.

*Jeff Trefftzs wrote:
> computer screen or printing on ordinary paper, I would recommend 
> something like ImageMagick to (a) reduce the size of the image 
> (resolution) and (b) convert from tiff to jpeg.
  I guess you  mean first make a tiff with lower
  resolution, then make a jpeg from that.

> Note that jpegs, even saved at high quality, look crappy when 
> you blow them up enough.  But when you resize the image first, 
> from a lossless encoding like tiff, then you lose no information 
> you will be able to notice at the desired end size.

  I think I get it. With some programs (including
 gimp) I convert a 100 MB tiff to a 250KB jpeg
 that looks crappy without blowing it up at all. I
 guess I need to reduce the resolution of the tiff
 first and then convert it. I'll play with that. I
 think my problem is because I am dropping the
 jpeg quality below 20% to get the file size down
 and it just doesn't perform well.`

> dependent on the grain size, and is usually on the order of tens 
> or hundreds of megabytes per snapshot/slide/whatever.  In my 

  OK, that jibes with what I saw. Particularly
 even small prints from a portrait studio have
 better resolution than my scanner can capture. I
 can find structure in the iris of an eye.  OTOH
 One series of snapshots that I have look fine
 when viewed at full scale, but the scanner easily
 gets all the available detail at less than max res.

> Were I getting hi-res scans of film imagery, however, I'd be 
> prepared to gobble up huge wads of disk space if I wanted to 
> keep as much of the original information as possible.
  Well, CDRs are cheap and can hold maybe ten to fifty
  of my  bzipped large tiffs.

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