I discovered this while experimenting with a way to make images look like pencil sketches. Imagine my surprise when instead it made the image look more real than before! Now it's become part of my regular post render workflow.
I am sure I did not originate this technique but more likely reinvented the wheel. None the less I had not run into it before . An example is in the Added Images link below.
Using part of an image by Dave Goetsch, I will walk you through it.
Solidworks - olsryd 9 cylinder radial engine
I created an Action file for to the Actions palette and you can download it below.
It goes in Photoshop/Presets/Actions.
But please follow the tutorial so you understand what is going on.
Hope you find it useful!
1. Open the image and duplicate the Background creating a new Layer, renaming it Layer1.
2. Desaturate Layer1...goto Image/Adjustments/Desaturate, (Shift+Control+U).
3. Duplicate Layer1, renaming it Layer2.
4. Invert Layer2...goto Image/Adjustments/Invert, (Ctrl+i).
5. Change Layer2 Blend Mode to Color Dodge.
The image may go blank with a few dark lines as shown...not to worry.
6. Goto Filter/Other/Minimum, set Radius to 1 pixel.
Very large images may need 2 pixels but rarely.
7. In Layers Controls, Merge Down Layer2 to Layer1, (Ctrl+e)
Set the layer Blend Mode to Multiply and adjust the layer Opacity to your liking.
Depending on the image you may want to set a Layer Mask and erase the effect here and there.