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June 27, 2013
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PremiereTutorialsVideo Editing

Video Editing: Additive vs. Subtractive Color Correction

Not all 3-way color correctors are created equal. Use a subtractive 3-way color corrector instead of an additive one for better results.

Video Editing Color Correction

Just like there are two types of color theory, there are two types of color correctors: additive and subtractive. Both old-school Final Cut Pro 7 and Premiere Pro (even the most current version) ship with additive 3-way color correctors built in. The problem is that additive color correctors don’t really give great results very easily. As a matter of fact, they can really be junk when it comes to making great looks in your video editing projects without a ton of effort.

Additive Color Correction

Look at the very simple adjustment below. First is the original and its RGB parade:

Before

Before Parade

When you add a little bit of blue into the shadows, look how the image and the RGB parade respond:

Image with additive blue in shadows

Parade with additive blue in shadows

Effect with additive blue in shadows

You’ll notice that the blue channel has been lifted – blue has been added into the image (look at the hair closely). The shadows on the image look pretty terrible, don’t they? The addition of blue has also lifted the black point of the image.

Here’s a more extreme example for you you compare to the original image and parade:

Image with more additive blue in shadows

Parade with more additive blue in shadows

Effect with more additive blue in shadows

Nasty stuff. Yes, you can make adjustments to the other controls to make it look a little better, but it takes a lot of work with minimal results.

Subtractive Color Correction

Now look at how a subtractive color corrector works. In this case, I used Colorista Free by Red Giant Software. It’s a great color corrector, FREE, works on a ton of platforms, translates to After Effects, and it’s pretty much my default NLE color corrector when I don’t want to go into a full-fledged grading program.

We’ll add a little bit of blue into the shadows like before:

Image with subtractive blue in the shadows

Parade with subtractive blue in the shadows

Effect with subtractive blue in the shadows

Notice how much more pleasing the results are compared to the additive corrector. Also notice that the blue channel in the parade pretty much stayed the same, and the other channels went down. That’s how a subtractive color corrector works: instead of adding the color you want into the shot, it takes away the opposite color (or really amount of the red, green, and blue that make up the opposite color).

Here’s an even more extreme example with Colorsita. Yes, the shot starts to get a little dark, but you still have a real black point, so you can just lift the shadows a bit to correct while keeping the pleasing look:

Image with more subtractive blue in the shadows

Parade with more subtractive blue in the shadows

Effect with more subtractive blue in the shadows

If you have a choice, you’ll find subtractive color correctors much more pleasant to use with better results in less time. It’s a no brainer when getting fast grading results in your video editing projects!

What kind of color correction filter do you use?
Share your thoughts and advice in the comments below! 

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  • Neil

    I’ve stopped using 3 way colour correctors completely and these days mostly grade using curves. Much better.

    • Aaron Williams

      Curves are great for total precise control, but you lose a lot of the intuitiveness and speed of the hue wheels, especially when matching quickly against color casts that aren’t strictly located in the red, green, or blue channels, but even in general grading. For pure contrast/luma adjustments curves are superior, but when colors get involved 3-way (or 4 way with an offset) is way more practical in my experience.

  • Guest

    Curves are great for total precise control, but you lose a lot of the intuitiveness and speed of the hue wheels, especially when matching quickly against color casts that aren’t strictly red, green, or blue, but even in general grading. For pure contrast/luma adjustments curves are superior, but when colors get involved 3-way (or 4 way with an offset) is way more practical in my experience.

  • guest

    is it better to do cc with colorista AFTER doing an initial luma curve adjustment to ensure the vectorscope shows a nice spread of luma,
    or is it best to go straight to colorista and deal with its white/black controls to get luma corrected, since luma generally is best done before color correction?
    im coming from a photoshop background where i get dynamic range corrected using the L channel and curve before color correcting using rgb or lab curves, so for video im thinking the orders of correction are the same : L then chroma. i just dont know if i deal with L before using colorista or let colorista do it using the wheel side sliders. i wish colorista had full point-editable curves in all 3 sections.

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