[GreenPeach]

I stole the ps users guide from work to catch up on my methods, thinking I was missing out because I didn't know how to use the chanels tools. And after a couple hours of expierement can''t figure out it would really be usefull. Using layers to seperate sections seems to work better, do you disagree?

[jcterminal]

well, there's a diff between channel tools and quick masking.

quick masking is really good for throwing down large sections of colour by hand, for blocking and whatnot. imagine the pink to be a sort of frisket or masking that prevents colour from "sticking" to that layer.

it makes sense if you've done colour separations or screen printings by hand.

(did that help at all?)

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j.c.terminal
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[GreenPeach]

thanks guys, that's what i figured.

[jcterminal]

w00t!

score one for PDX!

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j.c.terminal
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[edible snowman]

if your at all intersted at web design, its commonly used with lighting effects to.

[Waldo]

When I'm drawing and painting I go the layer route and don't use masking at all. However, one of my jobs is creating visual simulations (before & after shots of various developments) and I use channels and masks extensively. Channels help me save various selections and masks help me remove and recover data without permanantly erasing...

Just my experience.

edit- and the view sims are using photographs...

[This message has been edited by Waldo (edited April 03, 2001).]

[Pat]

Whoa whoa whoa! Channels and quickmasks ARE the same thing. When you hit "Q" to activate Quickmask, watch the channels tab... it will create a new channel called Quickmask. Essentially, the Quickmask tool is simply a reserved channel that you can turn on and off quickly for the purposes to editing. This is the SAME channel that is active whenever you make ANY selection using the lasso tool. Don't believe me? Make a selection with the lasso tool and then hit "Q". In fact, ANY new channel you create will serve the same function... it's just that Adobe saw the desirability to have one you could activate via the toolbox or keyboard commands for quick edits.

GreenPeach, learning how to use channels will VASTLY improve your ability to edit your images. They're fantastic for complicated masking operations and controlling filters, as well as precise airbrush masking. Understanding channels will unlock the full power of Photoshop. Channels (and combining channels) form the basis of all digital images. You might look at a nice RGB image of an apple and see a decent red. But Photoshop sees 3 grayscale images composed of 256 levels of gray stacked on top of one another known as channels. That red is actually 3 seperate grayscale values: The Red channel (ironically) contains perhaps a 5% gray. The Green channel contains perhaps an 85% value and the Blue channel about 90%. Mixed together they form a very particular shade of red. If you do the math, you'll see the logic: 256x256x256=16.7 million --which is exactly the number of colors you can accurately portray using the RGB color model. That's a lot of crayons in your box. But I digress: before there were layers, the Photoshop gods of yore used channels and channel operations (known affectionately as ChOps) to achieve amazing effects. Most of that has been supplanted by the ease of understanding involved with layers, but channels still have an important place in image editing --and in the case of digital painting-- a very helpful one.

A couple "for instances":

Suppose you want to change the color of a chain link fence you've painted without affecting the background. This could be nightmare given the thin, spidery nature of the fence. If you pop into quickmask, you can run the brush tool/eraser over the links fairly quickly and have them "selected" in no time. Much faster than using the lasso tool, IMHO. Often times you can take advantage of the varying levels of gray on the independent channels to use the magic wand tool for selections. If you examine the individual channels of your image, often times you'll notice one of them contains more discreet information relevant to your selection. You can simply select that channel, use the magic wand to isolate your selection (possibly even editing it's edges in quickmask) and then reactivating all the channels for the final color edit. By using channels, each image now offers you 3 opportunities for more accurate selections, instead of one.

More channel fun: load up a pic and go into quickmask. Run a few filters like clouds and difference clouds. Exit quickmask and then run some other filters. Notice what happened? The quickmask image protected parts of the image and allowed others to be "filtered" Careful thought here can yield utterly amazing effects.

Want to make Photoshop act like Painter? Need custom textured drawing paper as well as tools? More relevant channel fun: enter quickmask and run the add noise filter. Blur it a bit. Exit quickmask and then hide the selection. Now, grab one of your brush tools and begin painting. Viola! It's got a paper grain to it!

Beginning to see the possibilities? Believe me, it's just the tip of the iceberg --and an essential element of Photoshop worth exploring.

-Pat

[Waldo]

Thanks for that additional info, Pat.

[LazRath]

so basically it comes down to this:
the channels palette just is an interface that makes it a ton easier to save, load and work with selections

Summarization Complete

[Pat]

LazRath, ummm... no.

It's a lot more than that. Don't forget that many people use the intial 3 RGB channels for actually editing the image on a channel by channel basis. This has nothing to do with selections. If, for instance, I have a CMYK image and the yellow is a tad green, I just highlight the Cyan Channel and run an airbrush around the offending values to bring them back down to yellow.

I also use a 4th channel to hold B&W linework when coloring for comics because it accomplishes the same overlay as a layer, but consumes FAR less memory. I also use a 4th channel to hold my sketch while I'm painting so it's not overpainted. This works because additional channels OVER the number your image's color mode supports (ie 4th channel on RGB images, 5th channel on CMYK, etc) sit on "top" of the image just like a layer would when they're visible. Since they're only designed to hold 256 levels of tone (perfect for a black line or a grayscale sketch) it's much more efficient to use them instead of 24 bit layer.

Again, still the tip of the iceberg. I could go on and on about the virtues of channels when it comes to specialty printing and custom inks as well. Believe me, they're not just for selections.

-Pat

[GreenPeach]

Wow, pat. Thanks alot. I had no idea about a couple of your points. I will continue to try and figure it out.

[jcterminal]

yeah. pat was pretty damned thorough.

thanks.

me, i only use channels for bitmaps for texturing or for lighting effects....

(which basically work on the same principle.)

but shh! last i heard filters suck. so don't tell anyone you use them!

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j.c.terminal
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[badoli]

Another proof for that Quickmask=Selection theorie: ctrl-lmb on channel makes it the actual selection

[ceenda]

Sorry, I haven't had time to look through all the posts here, but the quickmask tool can be used quite effectively as a digital airbrush and stencil.

Use the brush tool at 100% opacity to make a stencil, convert the mask to selection and use the airbrush to shade in the stencil. It's the same theory as laying down a sheet of acetate and cutting out a stencil before airbrushing the area.

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Nicholas Anderson
web: Flying Islands

[Frost]

uhm, if quick masks mean that layer mask thing, then yeah, VERY OFTEN.

[stneil777]

well there is lots of things you can do with channels for instance you can make cool wires. Hard to explain but you make a new channel inside the cannel you draw what the wire will look like in white then you select inside the shite with the majicwond how ever it's spelled. then you use gossian blue to at about 9% or so. then go back to the layers with the selection still made then fill it in with a meduim color. then goto filter lighteffects then use two directional lights and at the button select the channel for the lighting effect bam you got a perfect looking shaded 3d wire here is a sample hope you do not mind.

if you do the same thing but make a sqaure in the channels area select it then fill it with filther clouds then go back to the layers and fill it with clouds agian brown and black then goto filter light select that channel you will get a 3d rock texture it looks really cool