Blend Modes

Normal
This only has a ’blending’ effect with reduced opacity – but it should not be overlooked, as the effect given cannot be produced with any other mode.

Dissolve
I can see no use for this, ever. If anyone has suggestions, please put it in a comment or send me a PM; I’ll add it in and give you credit at the bottom icon smile Blend Modes

Darken
This mode applies only dark pixel areas from the top layer onto the bottom – This mode is (perhaps oddly) not used to darken a picture, but to impose one on another. To darken an image, you could try using Multiply.

Multiply
Equivilant to placing one colour slide over another – densities multiply, and so the image darkens. This can be used to recover images that are too light by duplicating the original layer and setting the upper (duplicate) to multiply.

Colour Burn
By increasing colour saturation and contrast, this mode gives very striking results. It also darkens a little, but be aware that this mode often produces colours so extreme you cannot print them accuratly – ie out-of-gamut for printers.

Also in the Photoshop Tutorials category