Cropping doesn't downsample. It eliminates part of the data by
discarding some of the image.
Downrezzing is making less data from the entire bunch that's available.
Most people on my pro photo lists downrez by redefining the image
size. There is a lot of loss of resolution if you go from, say,
300/inch to 72/inch and some simply sharpen to compensate, since
72/inch is not supposed to be printable but corresponds to many
monitor resolutions. In reality, one can print from 72, or
definitely from 120, even 108, on one of those machines (Kodak or
Fuji) at file size pretty acceptably, and using a matte surface paper
allows one to get away with even bigger sizes.
So in the end it depends on your purpose. If you're going to print
you really ought to stay at least around 180/inch. If you want to
email it redefine the size at 72 and sharpen a bunch.
Resizing and sharpening are the final step before saving. Never
discard or overwrite your original capture (scan or digital) unless
you would discard the image anyway for technical reasons (poorly
composed, unsharp etc).
--
Emily L. Ferguson
mailto:elf@xxxxxxxx
508-563-6822
New England landscapes, wooden boats and races, press photography
http://www.vsu.cape.com/~elf/
