Making disabled icons - a question

[TheVaultDweller]

I forgot how I made disabled icons in the past (and after fooling around with numbers again for a while), exactly what brightness, contrast or hue, saturation to change and for approximately for how much. Help is much appreciated.

 

[teneur2g]

my method is to remove the silver border and then make a new layer, i make it 100% black, and set its opacity to 40%. then i make another layer, and i put betwen them two, i press alt+a then i pick the bucket tool and set opacity to 40%, i fil the screen with it, and then i make the selection 1 pixel smaller, press delete and set the opacity to 30% and fill it, then i make it one pixel smaller again and i press delete , set it to 20% and fill it, i do that until i reach 0%. but the fastest method is;

remove the border, make a new layer, set the layer's opacity to 40% and fill the layer with black. the larger version is to give a small feeling of a passive button, wich is kinda needed.