Noise Processing Questions...Why do you do what you do?

Started Dec 7, 2004 | Discussions thread
RaymondC
Forum MemberPosts: 64
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Re: layers def the way to go
In reply to rjbc, Dec 7, 2004

Thanks for your reply. I used this technique last night by setting the opacity at 25% and repeated the process 5 times. HOwever at the end I compared the results to a single layer application of Neat Image and thought them to be about equal. However, I was viewing at 100% on my screen and not attempting a blow up as you mentioned. I can definietly see how increasing image size of a nioisy image would have an ugly effect. Im curious, when you perfom the layering approach do you use a similar opacity? How many times to you repeat the process?

And let me add one thing here in the end, we are talking about fine detail here. I shot the basketball game with my D70 at ISO 1000, and a friends D1H at ISO 1600 and the results are astounding when exposed properly. The noise reduction just helps with detail and subtle clarity in the image. So I guess I'm asking about the different ways to use workflow to make good images better.

rjbc wrote:

well raymond, IMHO, Yves is one of the best posters here. I too am
a big fan of the layered approach: here's why:

Both Noise Reduction (NR) and sharpening are destructive processes.
NR perhaps more so. on close inspection, detail will quite
literally disapear. a watercolor like or plastic like effect will
also make the image look less "realistic" the more NR u apply. so,
using layers, u can control this degradation, go back if need be,
and, even better, using opacity u can turn the effect "up" or
"down" depending on how much you need. remember: the "amount"
needed is really dependent on print size: the bigger the blowup,
the more nasty that noise will look. lastly, the blended layer is
great because u can achieve a more subtle and natural look: by
"mixing" the original detail with the NR layer, u are getting
better quality than a "pure" NR layer even at its lowest setting.
its sort of like having your cake and eating it too, u get to keep
some fine detail, but get rid of some noise. if u do big blowups,
then u will really start to see what an art this is, as every flaw
and imperfection will magnify.

I have also noticed that when printing at lower dpi (ie 200-240 dpi
for oversize prints) the biggest giveaway is actually more the
quality of the noise than the actual detail. ie- a file at 240 dpi
has much more "natural" noise than a file say at 200. the detail is
obviously not as sharp, but you'd be surprised, sometimes its very
hard to tell the difference if you've done good NR! but, sans good
NR, it is very easy to tell bec. the more upsampling you do, the
more really weird and ugly the noise gets. its strange, but Ive
noticed that upsampling seems to mess up the noise of a file much
MORE than "real" detail. so, with good NR layers, u not only get
to print biigger, but even print better quality at lower dpi!

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