- Load an image (eg. Img1).
- Change it to RGB Color.
- Image > Calculations > Duplicate to a new file (eg. Img2)
- You might want to adjust color level at this time.
- Image > Adjust > Posterize (eg.7)
- Filter > Stylize > Find Edges.
- Apply Gaussian Blur.
- Image > Calculations > Multiply (Img1 by Img2) to a new file (eg. Img3)
- Adjust Levels to control the tone of the overall color.
- I haven't found a good use of this technique yet. This blurring will be useful somewhere.