Tutorial 001

How to produce accurate wall paint colour in Vray Linear Workflow

We won’t go into the detail of why and what is linear workflow. If you want to know more you can check out the recommended websites and video links at the end of the tutorial.

Getting the paint Colour

  1. Go to Dulux or other paint company website and get the RGB value of the paint.
    I usually go to http://www.dulux.com.au/specifier/colour/colour-atlas.
  2. For this example, I have picked Dulux Sugar Tooth (R214, G143, B161). I also download the colour sample file for comparison later.

Setting up the 3ds Max Scene

I am using 3ds Max 2015 with Vray 3.2. Make sure you have setup the linear workflow as follow.

1. In Preference Settings, click Gamma and LUT tab, Turn on the following: Enable Gamma/LUT Correction, Affect Color Selectors, Affect Material Editor.


2. In Render Setup, go to V-Ray tab and click Color mapping, change to Advance mode, make sure the mode is set to “Color mapping only (no gamma)”.

3. For the test scene, I just create three simple planes and a VrayDome Light.

Make sure the dome light color set to white and Spherical.

4. The top plane I use the normal VrayMtl with the RGB set to R214 G143 B161.

5. The middle plane I use another VrayMtl with diffuse map to VrayColor.

Click the color slot and change the RGB value to the paint colour RGB value. Remember to change the color gamma to 2.2.

6. The bottom plane I use the downloaded colour sample bitmap. When importing bitmap, leave the Gamma set at Automatic. If you are using the Dulux download sample file, you need to change the file extension from jpg to png. The Dulux website mess up the file extension.

7. You should get something like this in the VRay render buffer. Remember to turn on the “Display colors in sRGB space.

8. Save the render image to 24bit RGB png.
9. Open the render image in Photoshop and drag the download colour sample file into render image.
10. Use the Color Samplar Tool and check all 4 colours.

As you can see, you can’t get the correct colour without using VrayColor because the RGB value is not gamma corrected.
11. This is just the first step to get accurate colour into the scene. But normally I still need to adjust it in Photoshop at the final comp. Because you don’t normally use white light in your scene and colour is relative, the perception of colour changes depend on what’s in your scene.

Recommend sites for Linear workflow:
Neil Blevins
http://www.neilblevins.com/cg_education/linear_workflow_vray_max/linear_workflow_vray_max.htm
Tim Atkinson

Linear Workflow

Averis
http://www.aversis.be/tutorials/vray/vray-20-gamma-linear-workflow_01.htm
CGalter

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