I just read this one in a monthly tip sheet for Mac users. It comes originally from Scott Kelby. It's simple and fun to see.
Open a new image and either create a new layer or make the background layer into a floating layer by double clicking. Use the gradient tool and choose the stock Adobe gradient 'Spectrum'. Run the gradient across the whole canvas and then change the blend mode to Difference and draw the gradient in different directions. Voil?...
Open a new image and either create a new layer or make the background layer into a floating layer by double clicking. Use the gradient tool and choose the stock Adobe gradient 'Spectrum'. Run the gradient across the whole canvas and then change the blend mode to Difference and draw the gradient in different directions. Voil?...