bitmap color and vray color becomes diffrenent

[summerson1990]

Hi! I'm getting such kind of problem. If I want to place some bitmap to my model which already has some as an example diffuse color applied to another side of the cube. So the diffuse color of one side I set in Vray is in sRGB like 8 8 8 and I do the same in Photoshop, I make the color the same. But it looks different. So I found that I can input here (look my screenshot) the same value to my bitmap "Color offset" and color will become absolutely identical what can not be said if doing it with some values for example as some red color or any other (not black&white I mean). "Color offset" will not help and do colors look much more different but having no any manipulation with color will make them look almost the same but not 100% exactly. So why is this happening and how to make colors from PS look absolutely identical with vray color. Here is my test scene in attachments with b&w. But you can set to "side 1" of the cube some colored color and try to match to another side "side 2" with the help of bitmap made in PS and you should notice if very closely look that color are not fully identical.

[summerson1990]

The difference in vray color and bitmap color can be seen more strongly if you increase a little bit an exposure value. Look at my screenshot. As you can see there are some simple shapes placed additionally with the material from "side 1" (vray color) applied to them on the "side 2" which has a material with bitmap. And now you can certainly see this difference I'm talking about.

[nikoleta.garkova]

Hi @summerson1990

Thank you for the provided files, I had a look at your scene.

If you try to render with CPU you will probably see there is no difference in the pixel values. When it comes to rendering with GPU, you will have to take into account the GPU Texture settings.

When you use procedural colors (which are linear in principle), the total color amount will be much higher compared to an 8-bit texture color amount. Using an 8-bit texture gives less bit depth (less shade values per channel) compared to the procedural colors and will therefore render differently.

As you've set the render engine to GPU, in your Render settings and under the GPU Textures rollout you will find that Bit Depth is set to 8-bit per channel by default. This will clamp the colors of your bitmap and will give you a difference in the final results. If you set that to 32-bit float per channel, things should be good.

I've tried to explain it visually with your scene:


Let me know if that resolves your issue!