Banding in Gradation issue???

[Robb63]

I've got some highly glossy white and black surfaces (black one is attached) that I am having trouble with banding in the gradation in the lit glossy area. Any ideas? It seems as thought the HDRI aren't high enough res in the gradations?

I've tried the HDRI that come with KS, some from Dosche, and generating some in HDR Light Studio (at 10000x5000). All seem to have the banding in the graduated areas! My renderings are at 3000x2297 so they are smaller than the HDRI's I'm using (don't know if that's an issue or not).

Also, before anyone mentions it. I know these don't look glossy. My client doesn't wanted any kind of reflection in the surface, and since it's a completely flat surface the light doesn't do any nice bouncing or curving to show of a gloss finish.

[Robb63]

anyone

[Josh3D]

hey Robb, what material are you using? I've used hard shiny plastic, with just a touch of roughness for a similar look. is that blurry bit a label? or is there a label applied?

[br3ttman]

Hi Robb63,

Banding on whites and blacks has been a particularly annoying distraction for me as well.  There are a lot of factors that can contribute to banding (such as image compression, the software you're using to display the image, and the color range and resolution of your monitor.  When I first encountered the problem with my renderings in KeyShot, I thought it was the HDRI's and/or my quality settings.  After adjusting those with little success, I then created .tif renderings with alpha channels in KeyShot to rework the background gradients in Photoshop, but again, with limited success.  To be honest, I really haven't looked into the issue again until now with your posting.  I did find this You Tube video with some insight on using dithering to reduce banding in Photoshop: http://youtu.be/cGijQgw18e0

It'd be nice if our champions at KeyShot and forum community might weigh in on this with some additional tips and tricks.

[KeyShot]

It could be caused by using jpeg compression. Also, it depends on the program you use to view the image. I recommend rendering to .exr or 32 bit tiff to ensure the banding is not due to image compression.

[Robb63]

I'm using Photoshop CS5, so I would imagine that isn't the issue?
Also, I can see the banding in the preview (working window) and it looks exactly the same when rendered. Every HDRI I open in Photoshop seems to have some banding issues in gradated areas.

[m2tts]

The banding may be caused by the gradient being so narrow between what is black and almost black that there are not enough colors in the RGB gamut to cover it. Certainly this is true with monitors that can only show 24bit color (256 distinct shades between black and white). Someone correct me if you can indeed get monitors that display more of the color gamut.

[Speedster]

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Visit http://www.eizo.com/global/products/coloredge/index.html. 

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My 22" was about $1400 US, which is steep, but an investment I haver regretted!  Images are spot-on and AWESOME!  They have an excellent white-paper on monitors and ergonomics on their website.

FYI:  Be cautious about using too large a monitor, like above 28".  The excess real estate is causing an epidemic of "micro-tear rotator cuff" injuries, as I discovered the hard (and painful!) way before I got my 22" EIZO.

Bill G

[guest84672]

Thanks so much guys for your support!

[mmmster3d]

I've gotta say, I've had a lot of troubles with banding lately myself.  I was convinced it was HDR Light studio's gradient background- I'm still thinking that could be part of the problem.  Don't think its a monitor issue... I've beaten the material settings and environment settings to death to no avail.  Would love to hear anyone elses input on this.  curious to test out hdrls4..

i've tried the hdr's as gigantic exr's and also rendering out to exr or tiff 32 bit and no real difference.  what gives?

[rskk]

What helped for me:

Render in Keyshot as 32-bit TIFF, open your image in Photoshop(CC) and set the Image Mode back to 8-bit.