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
*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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