Avoiding POSTERIZATION? in CS

Natasa Stojsic

Avoiding POSTERIZATION when appling curves, blending modes, etc.

Any step by step aproach that could be helpful?

I know initial step is start with 16bit...

What say you?

Lovesong

I would say you need to experience the wonderful world of layer adjustments. First off copy the background layer, then select it, go to filters and convert it for smart filters. You can then do your adjustments, while controlling your fade, opacity, layer blending methods, and whathave you. I don't have my copy in front of me, but there was a menu under layers where you could select a to make a new adjustment layer- i.e. curves, levels (which is probably what you're looking for). Double-clicking on the space next to the layer name will open a dialogue where you will be able to control your "blend if" levels as well. Hope this helps. Let me know if I'm being vague.

Natasa Stojsic

Lovesong wrote:

I would say you need to experience the wonderful world of layer adjustments. First off copy the background layer, then select it, go to filters and convert it for smart filters. You can then do your adjustments, while controlling your fade, opacity, layer blending methods, and whathave you. I don't have my copy in front of me, but there was a menu under layers where you could select a to make a new adjustment layer- i.e. curves, levels (which is probably what you're looking for). Double-clicking on the space next to the layer name will open a dialogue where you will be able to control your "blend if" levels as well. Hope this helps. Let me know if I'm being vague.

Vague? not at all!

I did actually use layer adjustments, however after I finish there are signs of posterization, I mean the image looks fine but when you check the histogram your posterization is confirmed. Anyways, I have not used smart objects or smart filters. Are they part of the CS3? I heard with smart objects or Smart filters that you can alter the image as much as you want but you will actually not damage the file it self. So is that perhaps the way of avoiding the posterization.

Are Smart filters & Smart objects different from each other and in what respect?

Lovesong

Double click on the layer tab (you probably won't even need the smart filters-yes they are designed to be more flexible, but you're not damaging your image anyway if you use layers). Double click on the space to the right of the name, which will bring out the Layers Style dialogue. Shift around the underlying layers (you can also use option/alt-click to split them). Your histogram should improve.

BinaryFx

The image tone transitions are more important than the histogram for showing posterization. It is possible to make an image with posterization with a non combed (smooth) histogram - but the image still bands. It is also possible to have an image with a combed histogram and there is no banding on output to a given output device (while another output device may reveal the posterization).


Sincerely,

Stephen Marsh.
http://members.ozemail.com.au/~binaryfx/

Duffy Pratt

Natasa Stojsic wrote:

Vague? not at all!

I did actually use layer adjustments, however after I finish there are signs of posterization, I mean the image looks fine but when you check the histogram your posterization is confirmed.

If the image looks fine, then why are you worried about posterization? Are you trying to make good looking images or good looking histograms?


Duffy

pathfinder

Isn't adding Gaussian noise sometimes used to diminish apparent posterization also? This could be done on an adjustment layer also, I believe.

BinaryFx

pathfinder wrote:

Isn't adding Gaussian noise sometimes used to diminish apparent posterization also? This could be done on an adjustment layer also, I believe.

Indeed, Pathfinder, this is a blunt tool but it works, although I am not sure of an adjustment layer (is add noise now a smart filter in CS3?) but one can do it with an ordinary layer:

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


Regards,

Stephen Marsh.
http://members.ozemail.com.au/~binaryfx/