Simple Colour Correction

The idea of “correct colour” in digital imaging is flawed, as our view of real life is always tainted by the colour of light around us. That said, our eyes adjust well to various hues of light, whereas a digital imaging sensor ruthlessly records whatever lies before it. Sometimes, you’ll end up with unwanted colour casts in an image. How do you correct these?

Neutral Tones

Most forms of colour correction, whether simple or complex, rely on the image containing a neutral colour. Thus, a close-up of a red rose or anything similar, is inherently harder to rid of a colour cast. To correct colour, you must look for an element in the picture that you know to be neutral, whether it’s a grey cloud, a slab of grey concrete, or anything that should be black, white or grey.

Photographers often carry grey cards around so they can introduce such an element into an image, thereby making it easier to correct later. This method is not wanted in every photo, however, because it innately neutralizes colour. Some colour casts are desirable, like the warm hue of a late summer afternoon. Only images with obvious problems need correcting.

Simple Methods

Many raw photo editing programs will have a simple white balance tool, which you’ll click over a theoretically neutral area of an image. This eliminates any colour cast.

In Photoshop and other programs, you can apply a similar edit using “levels” or “curves”. This technique involves clicking on the middle eye-dropper found in those tools and then clicking on a neutral grey area of the image (or what would be neutral grey if it didn’t have a colour cast).

Another way to correct colour in editing programs is to use “colour balance” tools. The main problem here is that you’re relying on your vision, which is less precise than letting Photoshop correct the issue by numbers. Still, you might try that if the photo contains no neutral reference point, but has an obvious colour cast.