This question was posted in response to the following article: http://help.adobe.com/en_US/photoshop/cs/using/WSfd1234e1c4b69f30ea53e41001031ab64-77eba.h tml
I am not clear on what values are being used when the page refers to multiplying or dividing colors?
What happens when an RGB of (255,0,0) is multiplied by an RGB of (0,255,0) for example
For each channel (red, green, blue), the value from the target image (a) and corresponding blend image (b) are multiplied and the result brought back into range (e.g. for 0 to 255, multiply the two values then divide by 255).
var c = Math.round((a * b) / 255);