short and sweet

i think i would like a little description in there about what screen does.  A little definition of the blending mode would be nice.

Hmmm.  Without trying that,  I have no idea how making a duplicate layer makes the picture lighter.  Surly choosing blend loan alone isn't enough?

I will try it but I think it does need a bit more explaination.  If a person understands it, they can use it better than if they are just following something that they know works.

Choosing the blend mode along IS enough.

If you have a layer on top of another the bottom one will NOT show through UNLESS you either change the opacity of the top layer (make it a bit see through) or change the blending mode of the top layer.  By changing the blending mode of the top layer you tell photoshop how to mix the two layers.

It seems that Krauz has blessed me with some text.. i'll take the chance of suffering the wrath

"Screen Looks at each channel�s color information and multiplies the inverse of the blend and base colors. The result color is always a lighter color. Screening with black leaves the color unchanged. Screening with white produces white. The effect is similar to projecting multiple photographic slides on top of each other."  - a quote from the photoshop manual.

each blend mode has some interesting properties.  You can find out a ton of info pretty easily by searching for blend modes in google.