Make shades of the same color more visable

[Blighty]

I took your texture pattern and used Colors > Desaturate to make it grayscale. I then used  Colors > Colorize to colorize strips into different colours. What you could try is to increase the contrast on the grayscale image before using colorize.

But as Ofnuts said, the image is too subtle when only thin strips of it are seen.

Note: your texture pattern is indexed which could give you problems. Use Image > Mode > RGB