As you will recall from the Texture Types page, an albedo texture is similar to a diffuse texture except that it has had the lighting information removed. It is difficult to take photos that have all lighting information removed, and typically requires a laboratory lighting set-up to accomplish at the highest quality levels, such as those textures generated by Quixel. However, it is possible, using normal photo references, to generate an acceptable (not true) albedo texture for the creation of video games. If you would like true albedo textures, I recommend using Allegorithmic’s Bitmap 2 Material software. This software will generate albedo, roughness, ambient occlusion and normal maps from photographs that you import into it.
The Photoshop Process
This process will require Adobe Photoshop. It is intended to be representative of an albedo map, but is not a true albedo. However, if it looks good in-engine, why mince words?
- In Color Settings:
- change the color space mode from RGB to sRGB;
- underneath gray, change the Gamma to 2.2 if it is not already set there;
- and underneath Spot, change the Dot Gain to approximately 20%.
- With your image loaded in Photoshop, duplicate the layer and place on top of your layers.
- Desaturate the duplicated layer.
- Invert the desaturated duplicate layer.
- Change the blending mode of the desaturated layer to Soft Light. Process steps 3-5 have the effect of balancing the diffuse image (blacks get closer to grey and whites get closer to grey).
- You may have to desaturate the original diffuse image a little (-4 to -12).
- Using the reference image below, you can approximate the histogram (lumminosity) of an albedo texture for a particular type of material.
- Do this by selecting the albedo (a) color value from the image below, placing it into a separate Photoshop file, opening the histogram graph and setting the graph to luminosity, and observing the “Median” value.
- Compare that value against the median value of the original diffuse texture.
- You will approximate what the median value of your albedo texture should be. It will not be perfect.
- Alter the diffuse texture’s (your lowest layer) histogram median value by using a Levels operation and adjusting it to match (typically pulling the white value down) or be between the median value of a scanned rock’s median value (refer to the below chart) and your original diffuse texture. You should still only have 2 layers in your albedo file.
- Go back into the file and remove remaining shadows information (ambient occlusion).