2012 - how to: channel mixer
(or how to explore Channel Mixer with raiindust.)
Requested by longerthanwedo.
Seconded by firstillusion, kasiopeia & fuuurs.
The motion was therefore passed. This is the result.
For reference throughout this tutorial, I use Photoshop CS5, however I believe channel mixer is available on most (if not all) versions of Photoshop, based on the fact it is available on my copy of Photoshop CS.
Confession time. Yes, I use channel mixer, but I use it solely in relation to Yellow/Blue colours (favourite) and the ways it can help with upping the yellows of an icon without loosing the natural (or natural-ish) skin tones. However for the purpose of this How-To, I assume the fact that people would want to know more than that, so this How To became more like an experiment, exploring the basics of Channel Mixer and introducing it in a (hopefully) friendly manner.
THE BASICS
Channel mixer can be found in your adjustment tools (just like the rest of the colouring tools). It looks like this in my handy dandy little icon collection, but can also be found via Layer > New Adjustment Layer > Channel Mixer or Layer > New Layer > Channel Mixer.
What you need to know about channel mixer is this: there are three basic channels in which you mix. Red, Green and Blue (which is like most other colouring tools). The same goes for the colours each channel allows you to move between: red + cyan, green + magenta, blue + yellow.
Each channel has a main source channel that correlates to the channel you have picked.
Red channel -> red is the main source channel, while green and blue are sub-channels. Why yes, I did just make those names up for the purpose of this tutorial.
Green channel -> green is the main source channel, while red and blue are the sub-channels.
Blue channel -> blue is the main source channel, while red and green are the sub-channels.
The MAIN SOURCE CHANNELS are also set to 100% when you first open up the channel mixer. Having read up one some tutorials, I've found out it's good form to keep the TOTAL (found in the lower right hand of the icon) at 100%. This is something I've failed to do on more than one occasion with the Blue filter. However I'm okay with that but I'll get to that why later. When we finally get to playing with the settings (and take this off 100%), this is where the changes will occur. But there's one more part of the channel mixer left to introduce, and that is the constant.
The constant plays with the lights and shadows of the image you are working with. Moving the slider into the positive will play with the light areas (and move it towards the colour of the MAIN SOURCE CHANNEL), while moving it into the negative will play with the shadows, and move it into the opposing colour. For an equally as interesting (and more concise and explanatory introduction to channel mixer), consider checking out this tutorial.
EXPLORATION
First we need an image (or images) of some description to highlight the major differences between the layers. I've used three different images in the hopes of highlighting more succinctly what happens when you play with each of the channels. For references, my original screencaps are: Dany from Game of Thrones, Amy Pond from Doctor Who and Annie from Community. Each of them have a pretty prominent colour (blue, red and purple respectively) that I thought might help to show where some channels are more useful than others in colouring. To reach the base layer, I have one screen layer at 100%, and one soft light layer at 100%.
TOTAL AT 100%
(with nice, polite changes)
This is what happens to each of the base images while we maintain a 100% total, without going too extreme with the changing of each of the source channels. For reference, this is what I did to each of the source channels to evoke the changes.
And this is what happens to each of the base screencaps. Clockwise: we begin with the base, and move through the Red, Green and Blue source channels. Note that the red channel is the only one that actually plays with the colour the channel named? The green channel has a tendency to play with the magenta's more than the actual greens, while the blue channel plays with the blues and yellows equally.
TOTAL AT 100%
(with loud, arrogant changes)
Now we're starting to get to the exploratory part. I've pushed the source channels to extremes now, as far as they will go (+/- 200 is the breaking point). Please note that the main source channels can only be pushed to +200 to have their colours played with. If you attempt to push them to -200, then alter the sub-channels, the colours will not change. For reference, this is what I did to each of the source channels to evoke the changes.
Now we're talking some extreme changes to the base screencaps. Moving clockwise again from Base to Red, Green and Blue, again you might note that red is still the only source channel that really plays with it's named colour. We're still upping the magenta's in the green, and the yellows and blues are sharing equal rights in the blue channel. Does anyone else think that this is because red is a truly evil colour? Just me? Okay then.
TOTAL AT 100%
(combining our meek, loud and extreme babies together)
Ready to use the channel mixer to colour? I know I am. Here, we're playing with the input/output levels from the two previous experiments, but combining the Red/Green/Blue source channels together. So basically, we're colouring out image. Again, we're starting out with our base layer. Clockwise, the following image is that our of nice, polite changes all combined. After that, our loud arrogant changes. And finally, we draw to a close with only the Green and Blue source channels in play, taking the red out completely. I may think red is the devil, but I'd like to think I have a pretty good reason. Without it, the "extreme" use of channel mixer has done a pretty good job at colouring out images.
PLAYING WITH THE CONSTANT
Lucky last detail, before I branch off into unknown territory (aka playing with a total less or more than 100%). The constant. Light and shadows. And a lot more obvious when it comes to both gently nudging the colours (+/-20) and going to the extremes (+/-200). From the looks of it, this could be another way of introducing monochromatic tones into icons. And believe it or not, it makes me actually appreciate some reds (only in relation to the Amy Pond image that's full of reds already though).
The first lot of images are the differences between the constant (moving between the combinations of red/cyan, green/magenta and blue/yellow) changing the level between +/-20. The second lot of images are the differences between the constant changing the level between +/-200.
POLITE AND MEEK
LOUD AND PROUD
MORE THAN 100%
Phew. That seemed like a lot to get though. And all before we've even established that you can in fact, colour with the channel mixer. It seems daunting (but didn't selective colouring back in the day) but really, if you ignore everything about the total needing to be 100% and work with the way you're icon looks, then you'll be fine. Both of these were quickly thrown together to show the major (or minor) differences channel mixer can make in terms of colouring. The Pan Am image has only channel mixer, and we move clockwise from only using the green (with more than 100% total) into green + blue (not a big difference) into RGB. Where there is a difference, thanks to the reds. Woo, never thought I'd get to say that.
I'll admit, my love affair with channel mixer was discovered while playing with Quinn images, because for me, Quinn + Yellow will always be a perfect match. Unfortunately, when you're putting that much yellow into an icon (like I tend to do more often than not) there's no sure fire way of creating a decent contrast. The selective colour adjustment kind of, zaps the yellows too completely for my liking, and the colour balance adjustment just wasn't cutting it either. THANKFULLY, I discovered channel mixer, and the magic that is the blue source channel. Clockwise, we have a base image, and then a green only channel mixer layer. This layer looks a lot more natural in terms of the tones than the original base, which is another example of how channel mixer can be utilized. Then we have some curves + vibrance and a blue only selective colour layer, and then finally we added back in the green channel mixer layer, and ta-da. Nice vibrant neutral skin tones with tonnes of yellow to boot.
Really, that doesn't seem like a lot of exploring with actual colouring, but I honestly think that job is up to you. You have the caps, you have the power. Go forth and icon with the channel mixer.
IN SUMMARY
Or what I've missed, is the monochromatic option. Why? Because there's a perfectly reasonable, wonderfully written guide here about the perks of using channel mixer with the monochromatic option switched on. I think it's as good a guide as any, and you should therefore consider checking it out.
Most important lesson you learned from this tutorial should be: RED IS EVIL...
Kidding. Mostly. It hopefully will be that channel mixer is just like any other adjustment layer in photoshop. It provides you with a different, (yet again) varied way of adding colours to your chosen image. It can be intense, but it can also be a great mixture as long as you watch how it interacts with the image (look at me, getting all metaphorical). Play around with the different channels, work with them separately and together. Like all adjustment tools, there are draw-backs (HI RED INTENSITY) but as long as you fiddle with the settings to achieve colours that you want, all will be well.
If you'd like to know anything else, ask away and I will try my best to answer :)
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This was written for the Ask the Maker 2.0 meme hosted at icon_talk. If you have any questions (in relation to channel mixer) or anything else, the thread is always open, and I'm always willing to try.
As always, comments are love. Please let me know if you found this useful, or alternatively, hard to follow!