Ah ha. If I can use it for saving selections that makes my life ten times easier. Any links to tutorials are much appreciated. This should reduce the clutter in my layers significantly...
Ah ha. If I can use it for saving selections that makes my life ten times easier. Any links to tutorials are much appreciated. This should reduce the clutter in my layers significantly...
Channels are also useful in conjuntion with magic wand colour selections (which is what I mainly use them for). Quite often if you split a picture into its individual channels, one of them will yield much better magic wand selection results than the original. It also helps if you play with the brightness and contrast settings too.
Not sure how useful that would be in cartography terms though!
Ravs
Thanks for the tips. I've been playing with channels after these suggestions and found them to be really useful. I can see that splitting the colours is useful for photography. I'm primarily using them for keeping track of selections - one area for walls, one for floor, another for water and so on. It has made life a lot easier.
What's really interesting (well, it's interesting to me anyway) is that, as far as Photoshop is concerned (and Gimp too, I suspect), Channels, selections, layer masks, and the Quick Mask are all the same thing under the hood. They're a way for the program to say, "OK, if the pixel on the channel/in the selection/on the mask/etc is white, apply X effect at 100%. If the pixel is black, apply the effect at 0%. If it's somewhere in between, apply the effect at an equal percentage." If you follow Photoshop through it's various iterations, you can see how Channels evolved into all these tools which have different applications but are all still essentially the same. Pretty cool!
You'll find that the red channel contains most of the contrast, the green channel contains most of the detail, and the blue channel contains most of the noise. So if you've got a really noisy image, you can apply a filter like Despeckle or Dust and Scratches to just the noisy Blue channel instead of the whole image to clean it up, which'll keep you from losing detail, or sharpen your image by applying an Unsharp Mask to just the details of the green channel.Originally Posted by ravells
Channels are also really good for building complex selections instead of just saving them. If you make a new channel in the Channels palette, then click on the eye for any of the other channels there, it'll make all the other channels visible and turn your new channel into a rubylith overlay, just like the one you see when you use the QuickMask. So you get the convenience of creating a complex selection with the drawing tools just as you would with the QuickMask, but it'll be saved automatically when you're done because you're doing it all in a channel.
Sorry, it's late and I'm starting to blather!
And don't forget you can split am image as HSV in addition to RGB. That will sometimes give better definition for selections (i.e light from dark, regardless of hue) with the magic want tool.
-Rob A>
These are awesome tips!!!!!! As soon as I can I'll rep you both. Oh how I wish I knew this stuff years ago...
Bill Stickers is innocent! It isn't Bill's fault that he was hanging out in the wrong place.
Please make an effort to tag all threads. This will greatly enhance the usability of the forums.
hehe! I like my own typos - I think we all have a magic want tool
-Rob A>
I agree. Those are the kind of tips that I just don't seem to find in tutorials. Thanks for those.
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