KeyShot Forum

Technical discussions => Rendering => Topic started by: jeffw on April 01, 2011, 08:41:09 AM

Title: Eliminate dithering
Post by: jeffw on April 01, 2011, 08:41:09 AM
I am getting a color mottling which I think is called dithering when rendering a black paint material. I have doubled my samples and ray bounces but it is still showing. Rather than just guess at settings I thought I would see if anyone has dealt with this. Its kind of hard to see on this image but it is there. Thanks.
Title: Re: Eliminate dithering
Post by: Speedster on April 01, 2011, 12:43:09 PM
Black is really tough at times, and really tough if it's matte black.  Try making it "less black" by just a tad.  Also, try one of the hard plastics instead of paint- I find success with "Dragon Black" and "Cell Phone Black".

Just a note, you don't really need 64 samples, and just set your shadow quality at 1.000.  It will help a lot in other areas. and render times.  Try dropping your ray bounces to 6 or so, as I don't see any (?) glass.

Last, and I just learned this in the webinar yesterday- On the Realtime tab, set your Gamma to 2.2.  Not sure exactly what will happen but try it just for grins.  You'll have to adjust other setting like brightness, etc.

I'm sure others will pipe in with suggestiions as well, and be sure to watch Jeff's webinar (posted in the top area of the forum, as he demonstrated a black texture to the camera body.

Bill G
Title: Re: Eliminate dithering
Post by: jeffw on April 04, 2011, 08:49:18 AM
Thanks for the suggestions. I tried them but it did not eliminate the problem. What did seem to help was rendering it as a 32 bit tiff file instead of a jpeg. The trouble with this is it makes it hard to edit in photoshop as not all the commands are available in 32 bit mode.
Title: Re: Eliminate dithering
Post by: JeffM on April 04, 2011, 11:17:56 AM
Once you open it in PS change the mode back to 8 bit and see if the banding comes back. If so, undo and then go to 16 bit, your controls should be available then.
Title: Re: Eliminate dithering
Post by: jeffw on April 20, 2011, 11:00:04 AM
I would like to try adding noise as you suggest but could you be more specific. I am not sure what you mean by "creating passes for color and reflection" or an "AO pass". Are you saying apply a matt color to a surface and do another rendering?
Title: Re: Eliminate dithering
Post by: jeffw on April 27, 2011, 10:44:15 AM
Thanks. I will give this a try.

Jeff