# photoshop blend modes

19 Aug 2006i mentioned to merlucin that i had found a nice website awhile back with the

formulas for the photoshop blend modes. this is probably useful to others as well

so i'll post it here. www.pegtop.net/delphi/articles/blendmodes/. here's a summary so you don't have to navigate through all the links to collect em all.

multiply a * b screen 1 - (1 - a) * (1 - b) darken min(a, b) lighten max(a, b) difference abs(a - b) negation 1 - abs(1 - a - b) exclusion a + b - 2 * a * b overlay a < .5 ? (2 * a * b) : (1 - 2 * (1 - a) * (1 - b)) hard light b < .5 ? (2 * a * b) : (1 - 2 * (1 - a) * (1 - b)) soft light b < .5 ? (2 * a * b + a * a * (1 - 2 * b)) : (sqrt(a) * (2 * b - 1) + (2 * a) * (1 - b)) dodge a / (1 - b) burn 1 - (1 - a) / b

some modes use different formulas for light and dark colors and while this seems to work

pretty nicely in photoshop it can look ugly when things are moving around.

what i've found works well is to just compute both formulas and smoothly blend between them.