Suggestions on gamma setting in max

[moris7]

Hi guys!

 

What do you suggest for gamma setting in max? I'm currently working in 1.8 for both exterior and interior. I see some folks working with 2.2 and 2.0.. What's your best settings?

 

Thanks!!

[Devin Johnston]

Max+Vray=2.2 Gamma

[BrianKitts]

typically we are using 2.2 for exteriors 1.8 for interiors

[innerdream]

Sorry to barge in on this thread.

 

From what I have read gamma settings are directly related to your hardware and what you are viewing on. My question is why would you adjust gamma in 3d software? I'm curious because I see a lot of talk about it but it doesn't make sense to me.

 

Can someone explain the logic?

 

Here is an explanation of Gamma:

 

http://www.photoscientia.co.uk/Gamma.htm

Edited April 2, 2009 by innerdream

[innerdream]

Okay, I did some more reading. I'm on a Mac and my Gamma setting for my monitor is set to 1.8, I just calibrated my screen as well. Now I will set my software to 1.8 and all should be golden.

 

If you're on a PC your settings will likely be different.

[John Dollus]

Ya - proper gamma varies based on the hardware - LCD and CRT's different for example - my LCD is closer to 1.8 but the office standardizes on 2.2 so that's what it's set to.

[Jeff Mottle]

Okay, I did some more reading. I'm on a Mac and my Gamma setting for my monitor is set to 1.8, I just calibrated my screen as well. Now I will set my software to 1.8 and all should be golden.

 

If you're on a PC your settings will likely be different.

 

The Mac OS has a default gamma of 1.8, windows is 2.2 The next version of the Mac OS will finally get rid of their antiquated gamma setting and adopt 2.2 as their standard. 1.8 was used back in the days before color management as it more closely replicated the gamma of printers at the time. Now a days everyone should calibrate to gamma 2.2 as you get much better tonal range on your display and are less likely to see banding in your continous tones (gradients). Gamma 2.2 is also closer to the response of the human eye and how we process contrast.

 

Most displays including CRTs are gamma 2.2 or close to it. That's why the sRGB color space has a gamma of 2.2. It is a standard that was created to encompass the average gamut and tonal response of a CRT.

 

Regardless of your OS you should calibrate to gamma 2.2

Edited April 2, 2009 by Jeff Mottle

[innerdream]

The Mac OS has a default gamma of 1.8, windows is 2.2 The next version of the Mac OS will finally get rid of their antiquated gamma setting and adopt 2.2 as their standard. 1.8 was used back in the days before color management as it more closely replicated the gamma of printers at the time. Now a days everyone should calibrate to gamma 2.2 as you get much better tonal range on your display and are less likely to see banding in your continous tones (gradients). Gamma 2.2 is also closer to the response of the human eye and how we process contrast.

 

Most displays including CRTs are gamma 2.2 or close to it. That's why the sRGB color space has a gamma of 2.2. It is a standard that was created to encompass the average gamut and tonal response of a CRT.

 

Are you saying I should switch my Mac to 2.2? Thanks Jeff.

[Jeff Mottle]

Are you saying I should switch my Mac to 2.2? Thanks Jeff.

 

When you profile/calibrate your display the measured gamma is written into your display profile. When you use Photohop it will read this profile and adjust the images accordingly so that they are displayed at the proper gamma (the target you set when you did the calibration). However if you view that image on a Mac outside of a color managed environemnt, it will appear darker as the OS is still using gamma 1.8. Once the OS adopts 2.2 it will look the same.

 

As long as you are in a color managed environment and your display is profiled, it does not matter what OS you use. The gamma will look the same.

 

As for switching to 2.2, yes I would. Just know that if you are in a non color managed app the colors will appear darker than in Photoshop for example. If you are using bootcamp then 3ds Max will be using Window's, so the gamma will be fine even in outside of photoshop. The color won't though. that's another thread though.

[Jeff Mottle]

here's some additional reading if you are interested: http://www.gballard.net/photoshop/osx_22_gamma.html

[Jeff Mottle]

typically we are using 2.2 for exteriors 1.8 for interiors

 

That's really odd. If you are using a linear workflow properly that should not be required.

[innerdream]

Cool, thanks.

[moris7]

Ok , so should it be different for ext. and int. renderings? How can i check for my settings, i'm using lcd monitors. And then do i only change settings in max preferences? Or must i change also the color mapping/gamma in vray? It can get so confusing!

 

Thanks guys!!

[Jeff Mottle]

Ok , so should it be different for ext. and int. renderings?

 

No

 

How can i check for my settings, i'm using lcd monitors.

You need to buy a display calibration device to set or check your display gamma accuratly. You can use Adobe Gamma, but it's not so inaccurate, that it's not worth doing and you'll just end up screwing your colors up.

 

 

And then do i only change settings in max preferences? Or must i change also the color mapping/gamma in vray?

 

Both. Someone else will have to let you know the settings as I don't have max v-ray in front of me.

[danb4026]

I'm having issues with my colors. I use LWF with a 2.2 gamma setting and I have "Affect Color Selectors" in gamma prefs checked. That being said, I should not have to use Color Correction to adjust my colors, but I have to, because the colors are showing up too light. Color Correcting them to 2.2 with Color Correction makes then makes them too dark! So they are too light uncorrected and too dark corrected.

 

As an example, I am using a Benjamin Moore paint called Serengeti Sand with an RGB of 176,140,114. The attached image shows the EasyRGB color conversion from commercial tint to RGB (giving me the RGB value), the Benjamin Moore site swatch, the color picker and a sample render with the color on the trim.

 

All colors are the same RGB! 176,140,114. Why doesn't the color picker match the swatches??????

[Devin Johnston]

Your RGB values may be correct, the one thing your missing is your lighting in the scene. Once you start adding light it's going to change the value of your material colors especially if your using a GI based render engine.

[danb4026]

Your certainly right about the lighting, but that doesn't have any effect on the difference between the two swatches themselves.

 

Take a look below and the difference is obvious, but unexplainable to me.

[Jeff Mottle]

It depends how that site is actually calculating those RGB values. RGB values on their own are ambiguous numbers. They need to be tied to a color space to give them scale. If the color space that was used by that site was different than what you are using then they will not match.

 

I don't know exactly what is happening here, but it is very possible that that site based their RGB values on the sRGB color space, but you are working in an uncalibrated monitor space that is different than sRGB.

 

To see what I mean about RGB values go into Photoshop and create a swatch of color. Does not matter what it is. Then go to the info box and see what RGB values it shows up as. Now go to Edit>Assign Profile and assign a color space other than sRGB. Now The color swatch has probably shifted color depending on the color space/profile you chose.

Edited April 8, 2009 by Jeff Mottle

[Jeff Mottle]

I dont' know what that "Personal color viewer" app you have is, but I went to the easyRGB site and found this:

 

 
Where a physical sample of the color is available we store the spectral reflectance curve measured with a bench spectrophotometer. Where no physical example is available (for example Netscape colors) we store the original RGB values.
These are the most important parameters we use in the process:
Spectral data = From 380 to 720 nm in 10 nm channels
XYZ Illuminant = D65 (Daylight)
XYZ Observer = 2 degrees (CIE 1931)
RGB Conversion = Compressed sRGB/Rec.709
We chose the 2 degrees observer because of the sRGB recommendation even if we consider the 10 degrees observer a better choice for this specific application. 

 

So you can see they are using the sRGB color space. The illuminant they are using is D65 too. If you tell me more about that other app you are comparing against, I might be able to help a bit more.

[danb4026]

Thanks Jeff....I am operating in a calibrated monitor space. All of my monitors are calibrated to 2.2 gamma and 6500k white point.

 

I see what you mean in photoshop regarding changing the profiles and color shift, although the RGB values stay the same.

 

My profile in photoshop is typically set to sRGB IEC61966-2.1 ( i assume that is simply sRGB).

 

The Personal Color Viewer app is simply part of Benjamin Moore's website. The color was chosen from the Virtual Fan Deck at the link below: websitehttp://www.benjaminmoore.com:80/bmpsweb/portals/bmps.portal?_nfpb=true&_windowLabel=sidebarportlet_1_2&sidebarportlet_1_2_actionOverride=%2Fbm%2Fcms%2FContentRenderer%2FselectSideBarArticle&sidebarportlet_1_2np=public_site%2Farticles%2Fexplore_color%2Fec_virtual_fan_deck&sidebarportlet_1_2isNonSecure=true&_pageLabel=fh_explorecolor

 

It's in the Classic Colors Pallette and is Serengeti Sand, to be specific.

 

I took that color, and went to EasyRGB, from which I located that particular BM color and its RGB values. I entered those values into my Max Color Picker and that's it. But the colors are different. But EasyRGB and BM match perfectly, its the color picker that is off and, as I said, my monitors are all calibrated.

[Jeff Mottle]

sorry, yes the numbers don't change, just the appearance. Was typing faster than I was thinking

 

I've attached some tests I've done. The problem looks almost certainly like a gamma issue.

[Jeff Mottle]

and, as I said, my monitors are all calibrated.

 

Calibrating your display is only going to standardize your display to a known standard. In this case, as you are comparing everything on the display, it would not matter if your display were calibrated or not. Everything you are comparing against is in the same space regardless. If you were comparing to a physical sample and your display THEN a calibrated/profiles monitor and workign in a color managed environment would matter.

 

It's a gamma issue.

[danb4026]

Your good Jeff....and I have to agree that it appears to be a gamma issue. But it doesn't get much simpler that LWF @ 2.2. I really don't know what to do. It means that my colors in Max are consistently going to be off. There has to be a workaround.

 

BTW, beautiful photos on your Flickr.

Edited April 8, 2009 by danb4026
add

[Jeff Mottle]

Your good Jeff....and I have to agree that it appears to be a gamma issue. But it doesn't get much simpler that LWF @ 2.2. I really don't know what to do. It means that my colors in Max are consistently going to be off. There has to be a workaround.

 

BTW, beautiful photos on your Flickr.

 

 

Hi Daniel,

 

I was not sure where the gamma issue was happening, so I contacted a friend of mine at Autodesk (Pierre-Felix Breton). He's pretty much their color and lighting analysis guru. The problem is that the color picker is expecting Linear gamma values. Totally makes sense when you think about it. The values provided at easyRGB and BM are in sRGB color space (gamma 2.2).

 

While 3ds Max does not understand color spaces, it does understand gamma. sRGB has a gamma of 2.2, but the color picker is expecting values with a gamma of 1.0. Pierre-Felix created an excel spreadsheet for me that allows you to calculate de-gamma RGB values that you would enter into the color picker. You can download it here:

 

http://www.pfbreton.com/publications/cgtechniques/tips.tricks/color.conversion/sRGBtoLinearConversion.zip

 

Just enter in the sRGB RGB values and then it will calculate the Linear space RGB values that the color picker is expecting if you are working in a LWF.

 

In 3ds max preferences be sure to set your gamma to 2.2 and check the material editor and color picker checkboxes. That way you are converting the linear values to 2.2 gamma.

 

 

If you use mentalray, and use the Utility Gamma & Gain shader to pass the RGB values through, you can enter in the sRGB values directly from easyRGB and then set the gamma to 2.2 and check the de-Gamma checkbox. In this particular case there is a bug with the color swatch as it's applying the gamma twice, but if you look at the material in the material editor box, it does render correctly.

 

If you use V-Ray use the VRayColor shader. Set the gamma correction to "Specify" and the value to 2.2 Then pick the color swatch and enter in the sRGB values. As with the mental ray swatch the swatch has double gamma applied. The rendered material in the editor is correct.

 

Hope that helps. I'm going to write a short article about this workflow as I know others have probably experienced the same problem.

 

For those of you who do not want to download the spreadsheet or use either of the mr or v-ray gamma shaders, the formula to convert from sRGB RGB values (gamma only) to 3ds max Linear RGB values use:

 

(sRGBColor/255)^2.2)*255

 

 

BTW, thanks. Glad you like my Flickr pics.

 

For those of you who want to check out some of Pierre-Felix's past papers go here: http://www.pfbreton.com/publications/ some very good information here. His AU session are some of the best.

Edited April 9, 2009 by Jeff Mottle

[Devin Johnston]

This is amazing, I don't really understand everything you said Jeff but I'm amazed this is the first time this has come up. I've had this problem for years and didn't even know it I just accepted that RGB colors in Max were a little different than they were in Photoshop. So what happens when you have a bitmap that looks perfect in Photoshop, does it have the same Gamma problem in Max that material colors do?