View Full Version : JPG Artifacts


Balky
10-16-2002, 04:46 PM
Hi, I figured I would ask you...

How do you safely get rid of these colored artifacts that you can see more on the black?

Thanks

chiquitita
10-16-2002, 09:16 PM
If you just want to get rid of the color there are a couple of ways. You could add an saturation adjustment layer and desaturate the area, or you could add a color layer and "paint it black" which would accomplish the same thing. You could also add a multiply layer at a low opacity and "paint it black".

Sorry for the quotes, I couldn't help myself - I am going to see the Stones next month..

Doug Nelson
10-16-2002, 11:15 PM
The jpg artifact remover in Alien Skin's Image Doctor is actually pretty efficient at this.

Stephen M
10-17-2002, 12:19 AM
For the coloured noise, then methods similar to these techniques will do the trick:

http://members.ozemail.com.au/~binaryfx/IT_artifactremoval.html

If you Photoshop 6 or 7, I would personally look into the free actions listed in these links (there are three 'ISO' degrainers which all work very well on JPEG blocking), but if you can't run these actions then the ImageDoctor plug will be a non free solution:

http://members.ozemail.com.au/~binaryfx/PSTV_links.html#G

(the three links in the second row in the grain section).

Regards,

Stephen Marsh.

docilebob
10-21-2002, 09:13 PM
This technique works well sometimes, too.

Duplicate the original, if the jpeg compression has also desaturated the image a bit , CTRL+U to open the Hue/Saturation dialog and bump the saturation up a little more than you need.
Then Filter>>noise>>median setting of 3-6 (depending on the image) is usually enough, then Filter>>Blur>>gaussian at about 2-3.
Then set the top layer to color.
TA-DA.

:)

DBrigleb
11-07-2002, 03:04 PM
I just saw your posting after having added one of my own. From your attached example youre really showing color artifacts not really jpg compression blocks. See my posting for my approach to getting rid of color noise.