Preserved Topic: Channel

Im a newbie on photoshop and i am wondering what is the purpose of channel. I ve read some tutorials and most of them talk bout this command. Please someone explain it to me. I thank ya'll!

Channels contain the actual colour information that make up your image.

For example, in an RGB document (image) there are 4 channels, Red, Green, Blue, and RGB (the composite of the red, green, blue). When all RGB channel is active you see all channels as a composite.

Channels hold the information of how much each colour is present in an image. Channels are grayscale and represent the amout of each colour present as shades of gray. Pure black, or pure white in a channel defines 100% lack of that colour, or 100% presence of that colour. Shades of gray inbetween black and white depict lesser/greater amoount of that colour.

Alpha Channels are user defined channels that are used to store 'layer masks', or store 'selections' or make 'bump maps' (for use with the lighting effects filter).

More than likely, the tut you are doing is using a channel to make a 'bump map'.

Does that help?

thx a lot! It hepls me a lot.

Well put VP.
For more info and fun : http://horizon.nmsu.edu/alphachannels/

http://www.icdc.com/~ncassway/computer/photoshop-channels.htm
http://members.ozemail.com.au/~binaryfx/ST_utilitymasks.html
http://development.gurusnetwork.com/kpt/