Channels

Hey guys,

I guess sometimes teaching newbies like me is annoying. I could take the easy way ripping like most of the people does, but i do really want to learn, and i have a question, so if someone thinks tht spending his time teaching a fool newbie is something worth, thr it goes...
I know when we have an image even it is using "RGB" or "CMYK" collor mode, it is divided in channels, red, green, blue and so... this i can understand quite clear, but wht exactly is an alpha channel??? wht collor it represents??? Wht is it for??? Is there an article tht i could read about it??? I can manage it well, but i'd like to know it's concepts...

thx in advance
best regards

The alpha channel basically represents transparency. In graphical form it is of course represented as greyscale, with values ranging from 0 to 100% opacity. For example, a grey pixel on an alpha channel (50%), applied to an image, will give that same pixel on the actual image 50% transparency. A gradient alpha channel will make an image fade to transparent, and so on.

Hope that helps.

An Alpha Channel is a selection. Plain and simple.