Color Grading 102

This is part two of a three-part introductory series to color grading by Chris Packman, Head of Grading at The National Film and Television School. This series of articles is intended for those at the beginning of their color grading training.

In Color Grading 102, we’ll be looking at grading footage from various sources, using an EDL, and using shapes.

To start, we’ll review what color errors to look for in your footage.

What to look for in an image

This is a well graded normal looking image. It can be seen in the parade display at the bottom that the levels of the colors are good and there is no crushing.

This is the same image with a Red color lift error. The lift error can clearly be seen under the Red signal on the parade display.

This is the same image with excessive red gain. The gain error can clearly be seen on the parade display.

This image has a red color gamma error. Color gamma errors are the least easy to see on the scopes.

This image has a color hue error. Hue errors are common when dealing with ex 525 NTSC archive materials.

Grading is like building houses!

First you dig the foundations, then put up the walls, then the roof trusses and then put the roof on. Get it wrong and it all falls on your head!

First get your overall levels sorted using only the primary controls. Only when you have a good flat basic grade do you start to use the secondaries to deal with individual color problems. If you do not do this, you will find that your secondary keying comes apart when you start adjusting the primaries.

Loading our timeline

Give the project a name
Select the working Color space (Video SMPTE as our material is mostly Rec 709)
Select the resolution (1920 x 1080)
Select Auto Fit (our material is actually 720P, this will zoom it up to 1920 seamlessly)
Select the framerate 25
Select New Project
Select Open Project

Load your material

Select the video file (Colour_102.mov) and select import
Select New Composition
Drag the imported video file from the media browser onto the V1 icon.
You should now have some video in your composition

In this exercise we are going to use an EDL to put the cuts into our timeline. EDL’s are easily exported from most NLE’s. Select CMX3600 as the export format.

EDL’s are just simple text files readable in Notepad. This is ours.

Select Import and import the EDL (Colour_102.edl)
Select Record events only to mark current composition.
Import the EDL
Your timeline should now have cuts in it.

Looking through our timeline a couple of shots are in log video format, so we need to add a LUT to them.

Select the shot
From the menu above the layer tools select color management and LUT
Add an Input FX layer using the Input FX button below the previously used menu
Select the correct LUT for the material from the LUT path. (BMCC to Rec 709 in our case)

Our timeline has some archive material towards the end which has internal cuts in it. We can use the scene detect feature to add the cuts into our timeline.

Park the timeline just before the start of the archive sequence
Press the I button to add an in.
Select the scene detect icon
Nucoda will go and detect the cuts

Grading your sequence

You now have a sequence ready to grade.

Select Mems to get your grading environment
Work your way through the sequence first adjusting the levels then the color. Remember grading is like building houses.
If we have a shot that we are happy with we can save it into a memory and use it later in the timeline.

Select the memory to be used. A yellow surround will appear.
Right click and save note.
To apply the note double click on the chosen note and the settings will be applied.

Correcting the aspect ratio of the archive

Our archive is currently a bit of a funny shape so let’s put it right.

Select Pan Scan in the master layer.
Our archive is 4 x 3 which is scaled to 16 x 9. The correction for this in .75
Put .75 in Scale X
Save the correction in a note
Select the shot. It will turn Orange
Go to the end of the archive and shift select the last shot. All of the archive shots will turn Orange