RGB Values and VRayColor Gamma Matching Question

[jujubee]

It's been a long time since I've dealt with LWF and I see that Reinhard has eventually adopted.
This has probably been asked but I had problems searching for the answer.

Problem and steps:

1. I have a specific RGB/CMYK paint swatch value that I was trying to match.
2. However when I enter RGB values into the VRayMtl Diffuse Color Swatch, it's lighter.
3. I thought at first it might be GI or lighting related, or maybe I made a mistake (a client wasn't too happy.)
4. After double checking right now, I realized the brightened color swatch was likely due Gamma, so I added a VrayColor Map and set the gamma to 2.2. Now it appears to match like it should have.

Questions:

1. Why is this happening now?
2. Do I have to worry about converting and rendering older scenes for accuracy if something like this is way off?
3. Is there something I should be doing differently in order to use RGB swatches without having to use VRayColor and 2.2 every time I need a precise color match? If so, where and what should those settings be?

Tangential question (just to satisfy my curiosity):

1. Why have you defaulted to Reinhard over plain LWF (if I recall LWF was more accurate as I think Reinhard was a slight adjustment in either contrast/saturation - it's been over 10 years so forgive my memory.)
I remember having this "debate" ages ago when I had simplified LWF with instructions for others on the old forum.

I simply would like to be able to render out of the box without too much tinkering with these settings. so it's a surprise that it rendered that color way off.

[hermit.crab]

Where's your reference color coming from? Most likely the reference image has an sRGB profile applied (whereas its values are linear). Regarding the LWF question - things happen automatically now.

[vladimir_krastev]

Hi what is RGB Swatch? You mean you have an image let say jpg that you loaded in the diffuse channel of your VRayMtl? Send us this RGB Swatch if you can.

[^Lele^]

It's been a long time since I've dealt with LWF and I see that Reinhard has eventually adopted.
[...]
Tangential question (just to satisfy my curiosity):

1. Why have you defaulted to Reinhard over plain LWF (if I recall LWF was more accurate as I think Reinhard was a slight adjustment in either contrast/saturation - it's been over 10 years so forgive my memory.)
I remember having this "debate" ages ago when I had simplified LWF with instructions for others on the old forum.

As it comes by default, however, the Reinhard mapping is entirely linear (with burn set to 1.0).

Problem and steps:

1. I have a specific RGB/CMYK paint swatch value that I was trying to match.
2. However when I enter RGB values into the VRayMtl Diffuse Color Swatch, it's lighter.
3. I thought at first it might be GI or lighting related, or maybe I made a mistake (a client wasn't too happy.)
4. After double checking right now, I realized the brightened color swatch was likely due Gamma, so I added a VrayColor Map and set the gamma to 2.2. Now it appears to match like it should have.

Questions:

1. Why is this happening now?
2. Do I have to worry about converting and rendering older scenes for accuracy if something like this is way off?
3. Is there something I should be doing differently in order to use RGB swatches without having to use VRayColor and 2.2 every time I need a precise color match? If so, where and what should those settings be?

If Max is correctly set for LWF (again, it comes so as default. See attached image.), then the colors in swatches and pickers ought to be correctly gammaed.
In that case, then both you and/or the client may not be checking the source color under the right gamma environment (f.e. in PS without an LWF setup, in a non-color managed application , and so on.).
And if this is the case, then yes, you need to double-add a gamma to colors, but it's the wrong way around: you should rather be fixing the way the source is observed.

If the above isn't the case, then we'd need to get the source color and the scene where it doesn't match, to make tests of our own (this is quite unlikely to be the case, however.).

I simply would like to be able to render out of the box without too much tinkering with these settings. so it's a surprise that it rendered that color way off.

And rightly so.
Defaults provide for linear workflow under the sRGB color space, there is no need to tweak a thing.
Try and ensure you're at defaults across max and V-Ray.

[jujubee]

Where's your reference color coming from? Most likely the reference image has an sRGB profile applied (whereas its values are linear). Regarding the LWF question - things happen automatically now.

I used both RGB values I found on the the general Internet for a paint swatch (Benjamin Moore Rodeo) the first time and the second time directly from the BM website for Rodeo using a Chrome Extension "Hex Color Picker" which pulled up very similar RGB values.
You're probably right that it has sRGB values applied as the vast majority of RGB values found on images on the web are sRGB. I would have assumed that the RGB values I had entered into the swatch would have reflected that.
What RGB profile is VRay using by default then is it just plain linear?

[jujubee]

Hi what is RGB Swatch? You mean you have an image let say jpg that you loaded in the diffuse channel of your VRayMtl? Send us this RGB Swatch if you can.

Here's one web source. I wasn't using it as an image. I was manually entering in the values:
https://shop.samplize.com/products/rodeo-1534-12x12
RGB: 212, 205, 196

Again, by default in the diffuse color swatch popup values the CME preview shows it very bright and light. Only when I change it to VrayColor and set the gamma different does it resemble the one seen in the browser.

[jujubee]

you should rather be fixing the way the source is observed.

It's a brand new win 11 install. Default Chrome.
No color profiles were added to windows,
I haven't even set up my color calibration (X-Rite) either.
It's straight out of the box unless Windows, Chrome, and PS are all totally incorrect by default.

Double checked a few more color pickers and even ran it through PS - same RGB results.

Try and ensure you're at defaults across max and V-Ray.

Double checked my gamma settings and they're the same as you've shown.
That's the question I have, "across Vray."

Did something change in 10+ years? Where would this be if mat editor swatches are being impacted now?

[jujubee]

This may have something to do with "Native 3dsMax Material Swatches." Switching between the two have different results. When checked, the material looks correct. By default it is off.
I think I vaguely remember now something about this ages ago and having to use VrayColor as a workaround (it's been 10 years so please forgive my spotty memory.)

What purpose does this serve and why does this option exist if it's not matching accurate RGB values within a final output?
Do you generally keep this on by default? Does it (on or off) actually make any difference in the final output? (will test myself later.)

[Morne]

If you have the source on a web page, then no need for vraycolor
In your vraymaterial, just click the diffuse colour swatch, then use the eyedropper botton left of the color picker to pick direct of your web page color sample. (you first click and hold on the rainbow sample, then move out the window into your browser or other source material)
Max will automatically do the correct gamma adjustments and make the actual rgb darker. Visually, this will however match your source material.

You can confirm by putting your max diffuse swatch next to your webpage and do a screengrab, then sample both colours in PS from the screengrab and you'll find they match (even though in max it uses a different actual rgb - auto fixed via default gamma settings in max/vray)

[^Lele^]

It works just fine here, with defaults everywhere.
Native swatches or v-ray make no difference, the color pipeline is the same.
Is the scene brand new, or dragged out of the past?
If that's the case, there may be something left active, and you may want to reset the v-ray settings (switch to scanline and back).

What purpose does this serve and why does this option exist if it's not matching accurate RGB values within a final output?

The vrayColor? It has a few nice features (floating point input, fp multiplier, color space conversion) and it's a texture, so it can be used to map channels uniformly (something you would need a uniform color texture for, in some case).
For example, you could use a vraycolor of 25.0 float in a vraycomptex slot to clamp an HDR in the other comptex slot to that value.

[jujubee]

Thanks everyone.

In your vraymaterial, just click the diffuse colour swatch, then use the eyedropper botton left of the color picker to pick direct of your web page color sample. (you first click and hold on the rainbow sample, then move out the window into your browser or other source material)
Max will automatically do the correct gamma adjustments and make the actual rgb darker. Visually, this will however match your source material.

Thanks for the tip - didn't even know this was ever possible.

Is the scene brand new, or dragged out of the past?

Brand new, although I've been merging older assets and converting others from mostly Octane.

If that's the case, there may be something left active, and you may want to reset the v-ray settings (switch to scanline and back).

I'll give this a shot and report back. Although again when I check that "use 3ds max native materials" or whatever that does, the swatch color looks like it should look, but unchecking it makes the color much brighter.
I'm definitely not getting those results you are showing in your example mat editor - it's closer to white.
Just fyi I'm using GPU not the regular setting then passing this through Vantage.

[jujubee]

For now (about to reset), this is the difference with the gamma set within a VrayColor.
The one on the left has VrayColor and is set to 2.2 (which is what I need.)
The one on the right has the same exact RGB values but does not use VrayColor (default.)

[jujubee]

If that's the case, there may be something left active, and you may want to reset the v-ray settings (switch to scanline and back).

Unfortunately that did nothing.

[^Lele^]

For now (about to reset), this is the difference with the gamma set within a VrayColor.
The one on the left has VrayColor and is set to 2.2 (which is what I need.)
The one on the right has the same exact RGB values but does not use VrayColor (default.)

I can tell it's definitely brighter.
I was missing that you were using the GPU engine, but it shouldn't make a difference (also, i don't think it's used for the material editor samples, at all. But i need to verify this.).
Would you mind sending me a piece of the scene? (email in the signature)
Say, two nodes with the two versions of the material applied? You can apply the shaders to two cubes, select those, and then "save selected", which should make for a small file.

[jujubee]

I'll have to get back to you but yes.
It's weird right?