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[OM] Re: OT Web display frustration

Subject: [OM] Re: OT Web display frustration
From: Kevin Radloff <radsaq@xxxxxxxxx>
Date: Tue, 7 Jun 2005 10:51:25 -0400
On 6/7/05, Moose <olymoose@xxxxxxxxxxxxxxx> wrote:
> Sure, but the permutations are endless. If you have any pointers, I'd
> love to hear them. I did later try less sharpening in the downsizing
> process, then a little LCE to the display size image on a different
> shot, and I think it is an improvement, but not as much as I would like.
> 
> The big problem, as you say, is just not enough pixels to resolve the
> detail. Some things come through just fine. Others just get "funny" in
> one way or another. I think it is related to the size of the texture
> elements relative to the size of the final image.

Right.. I don't have all the answers and I run Linux so I'm probably
using completely different tools, but I'm rather pleased with my
recent sharpening work. ;)

I post lots and lots of images on my photoblog of sorts, all sized
down to 800x600 usually. Lately they've all been taken using an E-300
with sharpness set at -2. To prepare them for the web, I crop, adjust
levels, apply USM using around 0.6/50%/2, resize, and then sharpen
once more using GIMP's NL Filter plugin (0.2/1.0 or 0.3/1.0). The
light USM handles local contrast enhancement and lack of sharpness
without oversharpening. The NL Filter plugin's sharpening features
will enhance edges quite a bit before it has a noticeable effect on
noise, and doesn't usually have too much of an effect on perceived
contrast. I find this to be an optimal way to finish web preparation,
though of course there's no way around the fact that 800x600 isn't a
lot of resolution.

This being the case, my goal with landscape shots is to sharpen enough
with NL Filter such that plenty of "details" can be seen while not
oversharpening so much that the edges look out of place. The goal
isn't (and can't be, given the limitations) to be able to pick out
every blade of grass, it's to have just a few edges of blades of grass
visible so that the eye gets a sense of the sharpness despite the lack
of resolution.

I'm not sure if I've found the "correct" answer or if what I'm doing
is any close to being the "best," but it seems to work. And of course,
I presume you're not using The GIMP, which means my advice to use NL
Filter doesn't help much (I'm not aware of any equivalent plugins in
other image editing applications--but see
http://docs.gimp.org/en/ch07s06s05.html for The GIMP docs on it, and
http://netpbm.sourceforge.net/doc/pnmnlfilt.html for the pnmnlfilt
docs, from which the plugin is made). But, here are some recent
examples:

http://saqataq.us/pics/20050605/23.html
http://saqataq.us/pics/20050605/39.html
http://saqataq.us/pics/20050528/38.html

To finish up, I guess my advice would be to play with sharpening
algorithms other than USM. :)

-- 
Kevin 'radsaq' Radloff
radsaq@xxxxxxxxx
http://saqataq.us/
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