Playing in Photoshop
I admit that I am not a Photoshop power user, and there are far more tools in this program than I will ever learn. But occasionally I take a little bit of time and try to explore some of the effects. These are this morning's experiments...
Image, Adjustments, Invert
Image, Adjustments, Equalize
Image, Adjustments, Hue/Saturation & change the hue
Filter, Artistic, Poster Edges