KeyShot Forum

Technical discussions => General discussion => Topic started by: shamblingcat on September 17, 2013, 09:47:27 AM

Title: Color system
Post by: shamblingcat on September 17, 2013, 09:47:27 AM
Does Keyshot use a different color system than other software? I don't understand why entering the exact RGB values I want results in different numbers when opened in photoshop. This makes it very frustrating to match colors. A simple comparison is just looking at grayscale values. To achieve a 90% gray background in Keyshot I need to set the value to 1%. 

I've attached an image which should illustrate the difference I'm talking about.

Is there something that can be done to correct this?
Title: Re: Color system
Post by: Chad Holton on September 17, 2013, 10:13:05 AM
It's probably the gamma setting that you would need to adjust. Use a setting of 1 (under Project>Settings tab).
Title: Re: Color system
Post by: shamblingcat on September 17, 2013, 11:19:54 AM
Thanks, looks like that worked. Is there a way to not have the gamma setting affect the background color?

It seems like the default setting should be 1 to represent colors accurately.
Title: Re: Color system
Post by: Chad Holton on September 17, 2013, 12:31:40 PM
Quote from: shamblingcat on September 17, 2013, 11:19:54 AM
Is there a way to not have the gamma setting affect the background color?

Try using a backplate with the color you're after - gamma/brightness won't affect it.
Title: Re: Color system
Post by: Claus Jensen on September 18, 2013, 04:59:36 AM
You could calculate the gamma value of the color before applying it.

If you have your color (red, green, blue) in the value range 0-1 then the equations are

new_red = red ^ gamma
new_green = green ^ gamma
new_blue = blue ^ gamma

If you have a gray color (0.5, 0.5, 0.5) and is using a gamma of 2 then the new value would be (0.5^2, 0.5^2, 0.5^2) = (0.25, 0.25, 0.25). This would equal RGB 0-255 (64, 64, 64). So if you have a gray color in Photoshop with the value (127, 127, 127) then the equivalent color would be (64, 64, 64) when a gamma correction of 2 is used.

PS: another easier workflow is to avoid the math and use the eye dropper in the color picker. If you have enabled "Gamma correct color dialog selection" in Preferences -> Color Management, then this eye dropper will automatically do the conversion for you.
Title: Re: Color system
Post by: shamblingcat on September 25, 2013, 12:42:00 PM
Thanks Claus! That helped a lot. This is the first time I've used the eyedropper in keyshot.

Unfortunately it doesn't seem to work on secondary monitors which is where I'm most likely to have reference images open. Do you know if there are any plans to add that functionality?