Annoying banding issues

[sunnyc1]

Hi all,

We just came across this very annoying banding issue.
out of Vray doesn't seem to look too bad but at a close look you can see the bands slightly. The problem comes when editing. A very simple and slight Levels adjustment brings up the bands all the way thus ruining the image.

Original Output is 4000 x 3000 and it's been saved to TGA and TIF, both having the same banding problem.
MOnitor used, fairly new MAC 20"

lighting setup: VraySun+Vray Sky default + 2 IES

have a look at the images

Pls help !

original out of vray

http://img529.imageshack.us/img529/8...th10000ku6.jpg

zoom

http://img529.imageshack.us/img529/3...ngcopy2im7.jpg

Minor levels adjustment

http://img296.imageshack.us/img296/2112/bandingpp4.jpg

zoom

http://img296.imageshack.us/img296/8471/ddhq9.jpg

settings

http://img291.imageshack.us/img291/649/settingsuo1.jpg

[vlado]

You might want to save as either 16-bit or floating point image formats, so that you don't get these issues when editing the images.

Best regards,
Vlado

[sunnyc1]

thanks Vlado, but i tried saving to Tiff 16, Targa 32 and I'm stil getting the banding.

Do you think -6 -4 for 4000 px wide image could be causing it?

[vlado]

No, the actual render settings shouldn't really matter. What program are you doing the corrections in? Have you tried to do them in the V-Ray VFB instead?

Best regards,
Vlado

[gilpo]

From your render, it looks like you are using standard max lights (from the lack of area shadows). Make sure you are using inverse-square falloff. Also, I've found that if you are using the attenuation settings, max has the tendency to make the light 'band' as it decreases in brightness which may result in what you are seeing.

P.S. If you aren't using standard lights, please disregard the above

[sunnyc1]

i'm using photoshop CS2 for editing. For rendering i always use and work in Vray VFB

it's very weird but now I've moved from catmul rom to blackman and increased changed samples to -3-1 and the banding is slightly less but still there when leveling subtly.

gilpo thanks for the input. I'm using max's photometric free point + IES file at their defaults. they shouldn't be causing this i think, since i never had any trouble

[simmsimaging]

Not sure about the Vray settings, but it would not be unexpected in any image with that smooth a surface and a gradient across it. You may want to add some texture to your maps and/or grain it up a bit in Photoshop. It will be hard to avoid the banding otherwise.

b

[zeronove]

I agree; in a recent work I had a similar banding issue with VRaySky and solved it adding a bit of noise in PS; not a very elegant solution but I had the work done.