Masks VS Alpha Channels in Photoshop - What's the difference?

[PkennethV]

So far, I don't think I've once used an alpha channel before in Photoshop. I seem to be able to get everything done by using masks only. I am getting the feeling that maybe some of the things that I currently do with mask might be easier done with alpha channels, otherwise why would both features exist (or was one of them introduced in a later version of photoshop and the other was never dropped)?

So when do you guys use one over the other?

 

[PkennethV]

So it looks like no one really uses alpha channels then?...

 

[ChrisA]

So it looks like no one really uses alpha channels then?...

I don't but then I do photography not graphic design. Ask the guys who layout graphics to be printed of retail packaging or whatever. They have good use for transparency.

 

[Phrasikleia]

Alpha channels are great for when you want to save a mask for use on multiple layers or for later editing, or for when you want to combine masks using channel calculations (to get the difference between two selections or a combination of two selections, for example). I use them all the time.