Date: Sat, 30 Nov 2002 17:01:59 -0400 From: Jorge Parra
This certainly is 'goofy' procedure! If there is data lacking in a file you can't do much to recreate what isn't there. But the problem with the above technique is that the Photoshop user is relying on the histogram to assure themselves that they have solved the problem. You do also need to use your eyes and apply a little bit of logic as well. First, what you see on the monitor in close-up is not always what you will end up seeing in print. The print medium can be more forgiving than you might expect.
I am coming to you after having seen what was to me like some sort of gooffy
procedure , from a Graphic Designer I was working with. I was waiting to sit
with him to solve a presentation to client, and before that I just watched
him opening some PS files, tweaked colors, crop, unsharp masking
,etc-regular stuff-, just to see him checking the Histogram of one of
images, showing obvious signs of posterization.
Next, he just went to Channels and selected each individual channel, applied
a rather small Gaussian Blur ( like 0.4) to each Channel, went back to the
overall HIstogram and Voila!! No posterization.
A new unsharp masking to override the softness introduced by the Blurr and
this was it.
The scene was repeated with all files with no major checking.
The Gaussian blur filter is useful for a lot of things, but it can also *increase* the appearance of banding in an image, not reduce it. So if for example, you see there is some notable banding or posterisation in an image, you can resolve this by applying general or localised noise via the Noise > Add Noise filter. Adding noise is degrading the image of course, but is a smarter strategy than adding blur.
Martin Evening Photography <www.martinevening.com>
Co-listowner ProDIG discussion list <http://www.prodig.org>
Author of Adobe Photoshop 7.0 for Photographers
<www.photoshopforphotographers.com>
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