Image – Green = Magenta?

Friday May 3, 2013.

That’s right. When you enter the world of colour-correction and RGB, balancing light and colour in an image, the rules of colour we thought we knew don’t apply. Needless to say, although time consuming and at times confusing, it is a necessary part of video post-production. It allows one’s video to be, well, balanced out.

When you’re on set, you can have all the necessary lighting equipment, do all your white balances properly, yet when you’ve edited your video, the light and colour changes from shot to shot. This is normal. We cannot fully control light and colour on set. In a perfect world, it would be automatic and there would be no need for this task. Which is why people like Binky Productions and other companies offer this service. It’s okay if you don’t have the patience for it, and if you do, and you want to understand more or learn it altogether, then you’ve come to the right blog.

When it comes to colour-correction, stubbornness is a good asset. It takes trial and error, even with experience, you know the basics, but you need to figure out how much colour and light to add or take away. I use Final Cut Pro, so my examples will refer to that, but other softwares have colour correction tools as well. Once my video is edited and finalized, I add 3 things to all clips: 2-way color corrector, 3-way color corrector and RBG balance. I don’t use the RBG limit, personally it doesn’t make much difference for me, and I only use Chroma Keyer for the “Pleasantville Effect”.

If your image has a lot of light already, then I suggest only using the 2-way color corrector. 3-way tends to affect the saturation a bit, so I use it when the colour seems too intense. Sometimes you have no choice but to use both, however. In which case, you can easily raise the saturation to your liking. You have the color corrector tool with the bars and color adjust spheres, which I use for my first clip. Then I refer to my filter’s number reference for each change to enter the exact same numbers for each clip.

So lowering light or raising light is simple enough. Where it gets complicated is the RGB. Red. Green. Blue. If you know this, you’re all set. If you don’t, it’s important to understand how adding or subtracting one colour will result in another. You have a clip that seems yellow compared to the other yet when you add blue it just goes green but the other clips have a warm orange hue. And it’s not just adding red to that either, it’s do you add red to the highlights, the midtones or the blacks? You might even need to take some away from the mids while adding in the highlights to get your image the colour you want. Trial and error for the most part, but understanding how the colours affect each other is the key to finding the proper RGB quickly. With practice, your “trial and error” will become a quicker analysis of where and how much in comparison to another colour being added or removed and your work will become consistent and smooth and you won’t think too much about it.

Here is an exercise that someone recommended me when I began learning RGB and it has been the basis of my work that has become one of my expertise. Take a short video image that has been white balanced and is pretty neutral in terms of colour. Remember to take notes down, but in time you will know this by heart. First explore the colours one by one. Removing the red completely and seeing the colour it gives, exageratingly so. Same with the green, and you will see that removing green gives magenta. Try combinations of two and three, add red, remove green, add blue. Add red, remove green, remove blue, etc. have fun with it. Then take the neutral video image, copy and paste it several times. Give yourself the exercise to make it look like it was shot at night, then during a sunset, then in the morning, find other light circumstances you want to try, go from neutral day to night including a sunset in the middle, gradually from clip to clip. Anything you want to try, anything that seems impossible is quite possible. Don’t limit yourself, for the possibilities are endless.

When I first did this exercise, I wondered at how beneficial it truly was. But it shaped the development of my abilities in colour-correction. There are things you will understand without having been given an explanation for them. And you will continue to improve, and may change your method of working, as those skills improve. Of course, if you already know this, then perhaps you know of more tricks than I may know myself. That’s the beauty of it all, isn’t it. The basics are the same, but just as the various videos, the image, as much as the one who corrects it, is always different and ever changing.


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