[Rabid Penguin]

In a lot of photoshop tutorials, it will tell you to duplicate a layer twice, and then merge the two copies together. Can anyone tell me what the point of this actually is? It's bugging me.

[smarti77]

I dont think there is any point unless you are changing the blending modes (to multiply or screen for example which will change the final merged layer...)

[alastair_hm]

Unless you make changes to one of the layer it is not going to make any difference.
As said above messing around with the blending mode and opacity settings are required.

[Keith Alan]

A little known fact is that every operation performed in PS is done with layers automatically, whether you open them and blend them yourself or not.

If you're sure of yourself and what you're doing, opening new adjustment layers and then flattening the image are just extra steps that are time consuming.

[Rabid Penguin]

Fair enough. Thanks guys.

[shuttertalk]

It probably makes it easier if you want to disable the effect later or change your mind - just turn off the visibility of the layer, or change the opacity for a lesser effect...