A comprehensive overview of the Image Pipeline.
Colour Correction comes before Colour Grading. This entry is about grading – head here to learn about correction.
Indy Mogul‘s chats with cinematographer Jaron Presant, ASC and colorist Aidan Stanford, offer a fantastic insight into Image Processing – colour (or “color”, if you’re American) grading cinema and broadcast releases:
The entire Image Design Process – from planning in pre-production, to lighting and shooting during production, to digital manipulation in post-production – depends on formulating a plan and sticking to it:
“Discussing looks” – deciding on the colours desired at the end of the process, informs the choices that need to be made at the start of the process, such as:
- camera movements
- colour scheme
- story world
- Image Pipeline – at which stage in the process will which steps need to be taken to achieve the desired final image? How far “upstream” vs “downstream”?
- LUT (“Lookup Table”) – more complex colour “transforms” to the raw image than can be achieved by simple colour correction alone
- Tearing – different colours in the raw footage will behave differently. Similar colours, when pulled in different directions during the grading process, will create artifacts.
Putting into actions the various plans (lighting, camera, on-set colour correction) that comprise The Plan.
- Raw image (Dailies) – often flat-looking in colour, to allow room for colours to be pushed and pulled in post.
- Base LUT – the “starting look”. “A LUT is not a color grade,” says Presant, but a “base transform”, a quick way to preview how shots taken in different lighting situations will conform to the overall look you’re going for.
- Log-to-Log – more complex colour transforms, represented by Color Cubes. In this example, certain colours (green and magenta) are desaturated, while others (orange and blue) are saturated.
- Final Corrections – done by hand, because “a LUT, though very complex, cannot know where the pixel is in a frame” – in this instance: if the wall and the sky have the same colour value, the LUT will treat them both the same. It requires a human touch to recognize and distinguish between the two, and give each the desired colour treatment.
The completion of the process, according to The Plan. Includes such processes as:
- color targeting
- skin tone adjustments (more on these first three below)
- film grain
Gerald Undone has a bunch of walk-throughs on colour adjustment in post production, across multiple apps (Premiere Pro, Final Cut X and DaVinci Resolve). This tutorial focuses on matching colour, including skin tone, between footage from different cameras: