Texture Preparation: Removing a Color Cast using Curves
When taking your own pictures / photos for textures
you always have to watch out for color casts. Indoor areas might
generate warmer casts (orange, red) whilst outdoors cooler ones (blue,
green). If these color casts make it into your final texture, they will
most likely look out of place in-game and will be hard to pass off as
In this tutorial you will find out how to eliminate the cast so that you end up with a neutral image
The picture above, taken by myself last summer, shows how the sky emits
a strong blue color cast on all objects in the scene. Recognizing a
color cast is simple; are real life "white" items also white on the
picture? Obviously they aren't. To stay flexible we will proceed with a
, the curves adjustment layer
. Video here, explanation below (give it 2 minutes to load):
If you are using Internet Explorer, it will not load on this page. Firefox only!
- Add the Curves Adjustment Layer
- Identify an item which is suppose to be white in real-life, in this case we will take the cyclists t-shirt.
- Find the "white" spot which is in the middle of the curve (i.e. midtones), this is so that we can produce the most balanced end-result.
- When you have identified the sweet spot, note down the RGB values which you can see on the info box to the left. In this case R: 101, G: 131 and B: 174 .
the individual color channels in Curves, select the midpoint (as that's
where you want to have the curve) and enter the values in the before
field. Make sure the after field is set to 128. What the adjustment
layer will do here is automatically correct or bring down the strength
of any given color depending on your values.
If this were a texture, you'd want to tile it and apply specular & normal maps, a full process of which can be found here: Tutorial: Create Tileable Texutres
It's a simple process & technique, but very effective if you have
to convince your audience with realistic environments, feel free to
post any before and afters below