Martin Patek-Strutsky , Feb 10, 2005; 03:48 a.m.
Is anyone aware of a technique for correcting oversharpened images? I
plan to use some images taken with an old 2MP digicam but the in-
camera sharpening seems to be much too aggressive for todays
standards.
Ivan Dzo , Feb 10, 2005; 04:00 a.m.
a degree of gaussian blur with a very small radius would help - not ideal though as the damage is already done.
Oliver White , Feb 10, 2005; 04:20 a.m.
Sharpening is usually the very last thing you do to process an image. There may be a plugin that will "unsharpen" an image--in fact i'd google it if i were you--but for the most part, there is no way to correct it and go back to the same quality that was present in the original.
Chris Combs , Feb 10, 2005; 05:36 a.m.
photoshop:
1. duplicate Background layer
2. set mode to Overlay
3. Filters->Other->High Pass, enter, say, 2
4. invert layer (Ctrl+I)
Pawel Czapiewski , Feb 10, 2005; 10:50 a.m.
1. duplicate your image twice.
2. depending on the content and image size - gaussian blur on each of the new layers with radius say 0.5 to 4.
3. set first duped one to lighten.
4. second duped to darken.
5. adjust opacity
Martin Patek-Strutsky , Feb 10, 2005; 02:06 p.m.
Thanks for your hints. Will give it a try...
Gordon Richardson , Feb 10, 2005; 11:54 p.m.
Gaussian blur would be appropriate if a large radius unsharp mask was applied, but I find it hard to believe that an old camera would have had this function. Since simple sharpening was probably applied, the use of soften-filter is more appropriate. If sharpen-more was applied, then soften-more might be appropriate.
A small radius gaussian blur gives much the same effect as soften (with some easier control). I find that a fractionally softening user defined filter helps undo some of the damage. Don't try to undo all of the original sharpening (this is counter-productive).
Chris Combs , Feb 11, 2005; 12:09 a.m.
try the High Pass technique above. seriously, it's loads better than trying to compensate with Gaussian blur/etc.
John Mc. (Nashville) , Feb 22, 2006; 04:33 p.m.
My problem did not involve a camera, just an oversharpened image. The High Pass solution
suggested by Chris Combs worked extremely well for me. It didn't *completely* solve the
problem, but it helped tremendously. I suspect that a complete fix for an oversharpened
image is impossible, but the High Pass solution provided a very satisfactory result. I tried the
various Gaussian Blur solutions and the results were not nearly as good.
John Mc. (Nashville) , May 24, 2006; 10:59 a.m.
For what it's worth, had to adjust another over-sharpened image. Again, i used Combs's
advice. This time, it was a huge image (35" x 26", 300 dpi). The new overlay layer made a
small difference, but not very much, so I duplicated the overlay layer. The combination of
layers made a significant difference, so if you aren't satisfied with the results of Comb's
method, then try duplicated the layer again and see what you get.
