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Nuke VFX Fundamentals

Week 6: Merging and Colour Matching in Nuke

In this lecture, we learnt how to colour correct a sequence, the different colour spaces of a file, and how to import and export it.

We saw how to use ‘Grade, ‘ColourCorrect’, ‘Toe’, and ‘Blackmatch’ nodes to correct the colour of a sequence. These nodes can be used to correct specific parts of a sequence using rotos or to colour grade an alpha. Alphas need to be premultiplied to be added to the background plate, however, some alphas already come premultiplied, so in this case, we will add an ‘Unpremult’ node, then add the ‘Grade’ and/or ‘ColourCorrect’ nodes and then ‘Prebuilt’ node again.

It is also important to take in consideration the codec or colour space and linearization of the file imported as depending of what we are going to use the file for, we will need more information preserved in the file or a smaller size file. The files in a film production can be shared with compositors as LUTS, CDLs or graded footage. We also discovered the new ‘OCIOColorSpace’ node, which is used when the footage provided has already been graded.

And lastly, we saw proper ways to build up a map for grade and colour correct a footage, separating the primary and secondary colours correction, and then correcting the shadows in the last step. This way, if more amendments are requested, we can make the changes quicker.

The assignments of this week were to colour correct and airplane alpha to match its background and to carry on making some colour corrections in the previous mountains video using the roto created last week.

We also were asked to plan our air balloon sequence which we will be building up until the end of the term 1. My main idea for my air balloon video is to add a dark style, with neons and glowing lights, and add mist and thunders around the mountains.