Colour Correction Primer

craft
post-production

(Herman Wang) #1

At Bri’s request, I’m writing this quick primer that will help you get started with basic colour correction.

A few starting points:

  • Yes, I’m calling it “colour” throughout this column. I’m Canadian, that’s the way it’s spelt here.
  • This is not meant to be a comprehensive study of colour correction, it’s just enough to get you started. It’s a deep rabbit hole to dive into if you so choose.

This walkthrough will be using a clip from a music video I shot a few years ago. Here’s a sample of the raw footage:

I chose this clip because the wall in the background was white in the studio we shot in. Knowing that will guide us through the colour correction process. Once we get the wall to look white, everything else (like skin tone) should look “normal”.

Some starter points about colour theory:

  • All shots are composed of three basic colours at varying intensities: Red, Green and Blue, hence the common acronym RGB.
  • White is 100% Red, 100% Green and 100% Blue. This may seem counterintuitive until you consider the next point:
  • Black is 0% Red, 0% Green and 0% Blue.

The first thing to do is find the RGB Parade Video Scope in your editing program. You can’t really do proper colour correction without this valuable tool. The two axes of the scope are described here:

The horizontal axis of the scope is just the horizontal axis of your shot. Watch the scope as you play your clip and you’ll sort of see how that works. The vertical axis is intensity; in the digital world, 255 represents 100%.

Knowing that, I can now interpret the scope to see that the background wall on the left of the clip is represented by the three circled areas here:

The scope allows me to see two things right away:

  • The “white” has a little too much Green and not quite enough Blue. Remember for white, the three colour components should be equal.
  • The wall isn’t actually showing as white because the intensity level is well below 100%; it’s more a dull grey.

To solve the first problem, I’ll use a Colour Balance plugin. There are more sophisticated tools to do this job, but I’m keeping it simple for this walkthrough.
Plugin1

This has evened out the three colours as desired.

To solve the second problem I’ll use a Brightness and Contrast plugin. Watch the RGB Parade Scope as you change the values here - you’ll see immediately that this plugin is doing something quite simple, in terms of colour theory. I’ll adjust the values until the colours span all the way from 0% to 100%:
Plugin2

That’s it! Here’s the resulting processed clip. You can see that the skin tone looks realistic and the colours “pop” more.

I typically do this kind of work looking only at the RGB Parade Scope; I don’t even refer to the clip itself until the end, just to double-check what I’ve done.

If there’s nothing in your shot that’s white, you can always put something white (like a sheet of paper) in front of the camera during slate and use that to colour correct the rest of the clip.

One last tip for the shooting process: learn how to white balance your camera, and do it every time you change the lighting of your shot. This will result in clips that need less drastic correction during post.

I wrote this column up pretty quickly, so please let me know if you have any questions about anything I might have missed.


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(Bri Castellini) #2

Bless you.


(Robbie Ru) #3

This was a great article! It’s a crime how many times I color correct “by eye.” Thanks for the brush up!


(Herman Wang) #4

I do “mood” changes by eye, but only after I’ve done the basic calibration using RGB Parade


(Bri Castellini) #5

Is RGB Parade Scope compatible with FCPX?


(Herman Wang) #6

As I understand it, RGB Parade is an industry thing, not a software application thing. So any major editor should have it as a standard item. I don’t know for sure though.


(Robbie Ru) #7

Hey Bri! In this video that I linked to you in another post, this editor uses a RGB Parade Scope in FCPX. I believe you access it in the view option on the FCPX program window. Let me know if you have any trouble and I will happily help you out!


(Robbie Ru) #8

Actually, this may be of more help: https://support.apple.com/kb/PH12690?locale=en_US


(Bri Castellini) #9

Thanks Robbie!


(Bri Castellini) #10

HOLY SHIT HERMAN THIS WAS SO SIMPLE AND HELPFUL LOOK!

I literally did nothing but even the RGB color and up the brightness and contrast. holy shit this is a revelation.


(Herman Wang) #11

Looks much less washed-out, right?


(Bri Castellini) #12

OG color correcting:

New:


(Herman Wang) #13

Have you seen how Brightness and Contrast changes are actually very simple when looking at the RGB Parade?


(Bri Castellini) #14

Yes!! I am struggling a bit with telling which bit of the whispyness should be at 100 and I’m not sure if I’m using the right color balance area (I’m using “color board”) but it’s SO MUCH easier