Every pixel of a picture (smallest "dot" if you zoom in very close) can be recreated via R(ed) / G(reen) / B(lue) and alpha channels. Basically you can recreate any colour of the pixel by mixing R,G and B. The "channels" basically a way of separating the primary (RGB) colours into separatre planes. Has a few uses, one example would be printing although technically, Gimp should be supporting CYMK colours (something on their agenda for a while) for this purpose. The alpha channel governs the opacity (how transparent) of an area... the one thing that can't be reproduced by mixing the primaries. peterd - pral at paradise.net.nz wrote: >Aahh, I'm with you now. > >It's much easier to explain (and show) with The GIMP open (and an image >loaded of course) rather than via email. > >The three primary colours are red, blue, green, (RGB) - that is, as far >as physics (light) is concerned (forget the art classes back in the >school days when one was mistakenly taught "yellow" was a primary). >These three colours with differing %'s make up all the colours we see - >100% of each = "white" while, yes you're correct, 0% of each = black. > >The GIMP and other image editors seperate images into these three >primary's so one can edit each primary colour to amend, change, correct, >distort and so on as required. Each of the three primary's are refered >to as channels. > >Also, and nothing to do with the above, there are "alpha" channels which >is all about masking parts of an image - an alpha channel mask can be >created from one image or layer, then saved and used on another image. >(btw, layer masks can be used only to mask the _layer_ that the mask is >applied to - it cannot be used on another layer or image). > >Starting to make sense? > >Cheers, >Peter > > > > >Steve Withers wrote: > > > >>On Mon, 2005-08-08 at 21:11, peterd wrote: >> >> >> >> >>>Hi Steve, >>> >>>Are you refering to pixels, dpi, ppi, - resolution and that sort of >>>thing? or stuff like layers, channels, blending modes etc :-) >>> >>> >>> >>> >>The latter. I get layers (d'oh)....but "channels"? >> >>Wassat? :-) >> >>Steve >> >>------------------------------------------------------------------- >>To remove yourself from this list, email klug-request at linux.net.nz >>with "unsubscribe" in the body of the message. >> >> >> >> >> >> > >------------------------------------------------------------------- >To remove yourself from this list, email klug-request at linux.net.nz >with "unsubscribe" in the body of the message. > > > > > ------------------------------------------------------------------- To remove yourself from this list, email klug-request at linux.net.nz with "unsubscribe" in the body of the message.
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