Channels???

Hi...I'm new to Photoshop and I'm using version 5. What are channels use for??? and do I need them to create rounded corners on my rectangle shape???
Thanks in advance.

Channels are what all your images are actually made up from. If your image is RGB there is one RED channel, one GREEN and one BLUE. These when viewed together give you a full colour image. There are other color modes too which when use different formula to arrive at the final image.

The channels are always "greyscale" but they actually represent different intensities of the colors mentioned above. Go to Preferences - and choose "view channels as color" to see what I mean.

You can also create Alpha channels which you can use to save selections and create selections from. This is what most people use to really push the functionallity of photoshop.

Yes in version 5 you do need to use an alpha channel to create rounded corners. With PS6 there is a rounded rectangle shape tool. The technique you mean which is an old technique of blurring and then levels adjusting to create rounded corners still works - but its less accurate than using the shape tools.