I tried to use the "scratchs and dust filter" on one of my pictures which has a lot of sky. See attached. When I used more than 1 pixel in the options, the sky became posterized. I needed 9 pixels to remove the white dots in the sky. which gave extreme posterization in CS 6 Beta. The preview was fine, but when I clicked OK and the image was proceeded by the filter saw the posterization. I tried the same thing in PS CS3 and the results were as expected, no posterization. Had to reduce the size of image from 3688x2552 pixel in order to up load so if let me know if the original is needed.
I never did see system information on your other post. Can you paste it here? Photoshop help>system info
It might help with both posts. Can you send a link to the large fie and I'll download it and try what you did? (Jing, yousendit, dropbox or email if it is small enough.
Thanks for your file. I tried it on both CS5 and CS6. I get the same behavior in both CS5 and CS6. Because of the amount of dust and size of some of the speckles, you might want to use the healing brush on the larger scratches and white blobs in the sky and on the sidewalk and then apply the filter. You could also duplicate the layer and apply the filter and then create a mask so it only shows through in the sky or sidewalk area, thus not posterizing the trees and buildings.
Thanks, I was just experimenting to see what the Noise and Scratches
filter would do, I realize that the healing brush would do the job. As
you suggested I was going to duplicate the base layer and use a mask to
show the sky area..
Were you seeing the posterization? If so, try doing it in CS 3 to see