Yeah yeah yeah I'm still about.
Right I'm gonna tell y'all about colour theory now because I'm sick of seeing your boring desaturated pictures with your shitty Michael Bay orange-cyan overlays.
Yes we should all start here. Some people will have realised this stuff without ever having to read a pretentious, arrogant and overly aggressive Briton's tutorial on it because they can do something which I like to call "using their eyes". Btw that applies to about 1% of this forum.
The colour wheel:
I hope to god you've all seen on of these before. I even got a picture of a labelled one to really help you out. This thing doesn't just apply to art - Isaac Newton invented this baby; that's how cool it is (when something is still used 400 years after its invention you know it's good).
"But Chesty, how is this going to help us? It's just a picture of all the tertiary colours!". It'll make sense shortly, don't worry.
I'm going to assume you're all over the age of 13 and so have had the wonders of combining primary colours to make secondary colours and then tertiary colours explained, if not there are links at the bottom that contain the info in them.
What we're concerned with here, and what we're going to use the wheel for, is understanding colour harmony. Every piece of artwork should have a colour-scheme. Colour-scheme is almost as important as your posing and all your fancy explosion effects. It's a key part of composition that is as vital as picking a sweet camera angle. Looking at the way most of you work I'd guess that colour-scheme is the absolute last thing any of you think about... and I can't blame you entirely for that because you're working initially with the Source Engine so you have to pose with no colour scheme at all. For the love of God though, once you're done with your posing and effects/shading editing you should really be taking far more than 2 minutes thinking about colour-scheme, rather than just desaturating a bit and slapping on your orange-cyan colour gradient and calling it a day.
There are two typical ways of creating a harmonic colour-scheme.
Through analogous colours:
Analogous colours follow each other on the wheel. This method is easy to do and can make a nice, simple image with a clear mood or theme. It's not terrible exciting though.
Through complementary colours:
Complementary colours are [i]always opposites on the colour wheel[/b] - this is impotant. This method is more difficult to use but creates far more stunning imagery.
You're gonna be limited to how well you can enforce this in Gmod what with the choice of models and materials available to you. If you ever get the chance to use analogous colours or complimentary colours in-game, then you should really take the opportunity because it won't come along often.
So sure, by the theory above, your shitty blue-orange colour filters are nice, complimentary colour-schemes... but God there's so much more you can do.
DIS WHERE IT GETS GOOD
Shading and highlighting with colour:
Colour theory is most applicable in shading and highlighting. Choice of colour gets more involving once you're finished with your midtones (ie. the flat shit you get once you've taken your Source engine picture) and you start to get into the extreme darks and lights of your artwork.
What most people fail to understand is the exact reasons why opposite colours are so complimentary. The simple reason is because you see it all around you without even noticing and, if you apply it properly, it shouldn't be noticed in your artwork either - it's just that natural. Complimentary colours is simply an optical illusion:
Fairly strong orange/yellow light is striking the sand. The shadowed areas not being hit by light, in contrast, looks blue - the opposite of yellow/orange.
You can apply this in varying degrees to artwork, partly depending on how strongly saturated your light-source is but also partly to do with how striking a visual style you wish to create:
Or something much subtler:
Using colour like this you can get some really natural depth in your work.
Things get more complicated when we start working with more complex materials, however, especially skintone.
Here's a digital art skintone study I did a few months ago:
(as with any other digital work I post, it's made from scratch on Photoshop CS5 using a Bamboo Pen tablet)
At this point I wasn't using complimentary colours in my shading and highlighting very much but some of the fundamentals are still there. Note that skintones get more saturated, and therefore redder and browner, as they get darker, rather than just getting progressively blacker. Also note how the highlights in the colour pallets are actually mostly cyan. Using black to shade is pretty much the worst thing ever. It makes materials appear lifeless and flat:
The one on the left was my original study, the one on the right something I knocked up quickly to show how wrongly it can be done. Note how flat the one on the right is and yet if we compare them monochromatically, just to see the tones:
They're actually almost identical. The power of colour!
As you can see, skintones get more saturated as they get darker, therefore making them redder and browner. Making skintones more saturated in the shadows is only half of it though. Mixing in a small degree of complimentary colour theory into it works wonders though. Under normal, semi-yellow lighting, a small measure of purple in the shadows and a small measure of cyan in the highlights works wonderfully.
Things get even more complicated when you have to take multiple light-sources into account:
Overall the lighting is orange with strong orange lighting coming off from the left and in-front somewhere. But on the right you've got a softer cyan light. It can get quite confusing. So on one half of the picture you've got cyan highlights and orange shadows, while on the other side you've got orange highlights and purple shadows.
"BUT CHESTEH HOW IS ANY OF DIS APPLICABLE TO GMOD GRGNNh!?"
Right, okay. You've come this far so thanks for reading. Now we can get on to how to use this theory in your editing. Sure, I probably could have told you this straight away but then you'd just be mindless zombies following my command as if my artistic opinion suddenly means more than everyone else's for no apparent reason. You should always understand why you're doing something and why it looks good before you apply it.
You're probably wondering right now "but... we're working with pre-made models and maps. 90% of the lighting, colour, shadows and highlights are already done. Surely all I can do now is get my dodge/burn tool and shit all over my picture with it?" Well you're wrong. If you feel the need to add proper cast shadows and self-shading to your pictures, which you should unless you're a God at using the lamp tool like Urbanator, use your burn tool set to "highlights" to put in some black/grey shadows as you would normally.
But remember what I said about how shading with black looks shit? Well that's still true and that's all you're gonna get by using the burn tool. What you want to do now is use the colour-balance (CTRL+B) settings properly. By that I don't mean set it to midtones and then make your picture as brown as humanly possible.
Take note of the colour of your light-source. Now, set the colour-balance setting to "highlights". Change the balance so that the highlights are the same colour as your light-source (although not nearly as strong). Next, set your colour-balance setting to "shadows". Now change the balance to the opposite of your highlights colour.
"Holeh shit Chesteh it looks like I just turned the contrast up too much!". Don't worry. It does increase slightly and you can decrease the contrast manually if you feel the need. If you compare the monochromatic tones though you'll see that a lot of it is due to optical illusion; remember what I said earlier about creating depth in your pictures with colour? You just did it. The picture appears to have a lot more tonal contrast because you have created real colour contrast.
Let's see it in action!
Here's a really average picture with some fairly decent cast shadows, contrast and shading... but it's so flat and lifeless. Maybe this is due to the shitty orange-blue colour overlay.
Let's apply what we learnt about colour theory using the colour-balance settings. We've got orange light from the fire, so lets set the highlights to have red/yellow balance and, as an opposite effect, we'll set the shadows to have blu/cyan balance:
Instantaneous colour depth. And what does it take? A bit of knowledge in traditional artistic technique and less than a couple of minutes to implement on top of all your other editing.
NOW GO HAVE FUN!
sum1 st1cky dis cos it iz sik