Color Tip: Node Sequencing and Node-tree Organisation
Updated: Mar 21, 2021
So, if you have read my previous blogpost about finishing my first color job (here), I have mentioned about node trees of my grade and how I transformed from creating nodes after nodes, and at the end of it I managed to create and sort them out in an order according to the adjustments, for example global adjustments, secondary color-correction, giving a look ... So, I'm here to share my workflow of sorting out my grades - this can be extremely beneficial when you start practicing long-form coloring or a gig with many shots.
1. Overview of DaVinci Resolve (DR)
For those who have not heard of or experienced DaVinci Resolve, it is a powerful software widely used by professionals for color-correction and color-grading (you can actually backtrack the UI difference of Resolve 17 and Resolve 12, or any versions before). It gradually grows by integrating more features under the big umbrella of DaVinci Resolve, such as Fusion for Visual Effects (VFX) and Fairlight for audio-processing. Unlike any of its competitor and it may sound too powerful to be true, Blackmagic Design actually releases Resolve for free and to get more professional users switching to the platform, which I find it smart and generous for its brand image. First, get new users to experience the operation. Once they're familiar with it, they are willing to pay more for the powerful features. The learning curve of going for the Studio version is actually quicker.
Among different NLEs (i.e. Adobe Premiere, Final Cut Pro X and Resolve), they share the similar philosophy for daily-editing purposes (for high-end ones like AVID could be another story), so learning it would help beginners grasping the idea of post-production if you consider to be an editor/content creator, especially considering the powerfulness of Resolve in a single-package. Plus, you can actually complete the test authorised by Blackmagic Design to be a certified user, and it looks really cool to put it on your CV or LinkedIn in business/marketing purposes (that's what I did during my time interning in NYC and claimed my certified user certificate) ;)
2. What is coloring? How do you color in Resolve?
Basically coloring (includes color-correcting/grading) in Resolve is like working on your dinner recipes, as in working on a shot means preparing a dish; we apply different ingredients step-by-step, one step followed by the another step. At the end, it's about how to match the tastes of different dishes in the meal.
To be specific, wash the meat you got from the market, and marinate it next for flavouring... This is how Resolve works, and each adjustment is represented by a node. You apply your changes (or effects) with different nodes (tiny boxes and each with a number, a frame preview and some other things...) from left to right (you can't change the direction, as this is the intuition of how the software works).
In most cases, you start with node #1, #2 ... until the final adjustment you want to make on the frame (which can be #10, or #25... depending how much you want to tweak around). This is what we called the 'serial node' adjustment - all changes are applied one-by-one sequentially, as in you are queuing in a fast-food store. Essentially, the layout of how you're lying your nodes in the node area is called the node tree. Each colorist may have his/her preferences in sorting out a unique node-tree. But we all generally share the similar rule of categorising them in a similar order - from left-to right, plus from correction to stylizing. You can basically drag the nodes to reposition as in any ways you like.
In this example, what difference(s) do you see in the node-tree layout below? As you begin to work on different projects, you start to figure out your way to sort out your node tree.
A node-tree overview of two interviews (3.Leticia vs. 8.Ron)
1. Basic color-correction
Normally, we first create some nodes to correct the image before applying any grades (the 'effect' or 'style'). It helps to set the look quickly if you have all shots balanced, and you can bring in and apply the look to get all shots identically stylised. First, we leave the first node empty to be spared for adjustment (I'll explain this later). Then, create the second node to balance the luminance, and balance the color in the third node so we can separate each control and leave us more flexibility in tweaking them. Once this is completed, we have a base-point to start setting looks in different parts of the frame.
2. Secondary color-correction/adjustment
Take Leticia's interview as an example, we have already had the first three nodes here for the correction (01 - spared node; 02 - luminosity; 03 - color balance). In order to keep the image naturally-stylised, I created the 4th node for skin-isolation (as we are very sensitive to skin-tones, a bad skin-tone can skew our perception of the mood and makes it hard to look at). So, I am going to make 9 partial adjustments on the shot without affecting the skin-tone. For example, brightening the sofa, tinting the lamp, boosting the contrast of the magazines ... These are known as secondary color-correction, which we highlight and isolate a specific area in the shot for a specific adjustment.
Sometimes I find the term secondary color-correction confusing as we also apply adjustments to set the look, I may reference this as partial adjustment in the following explanations.
3. Global adjustment - setting the look of the final image
After tweaking the details around, the look is basically set. I created a few serial nodes to give an overall contrast-punch and have a better focus on Leticia with vignetting. This is how the interview look is set. Sometimes we don't have to create a dramatic look and the adjustments can be really subtle to see, but it does contribute to shape the way how audiences are looking at her - more energetic vs. calm, objective. Vignetting, film grain and glow can also be applied here.
4. Spare adjustment in the first correction-node
Sometimes if we are filming in a low-lit environment, the camera may produce the images with color-noise, which can be terrible for making secondary color-correction/adjustment as we may easily highlight some unwanted areas due to the color noise patterns. We may apply noise reduction here to clean-up the image so we can get a cleaner key of color with the qualifier tool. This is not necessary, depending on how rough the image is for picking up the colors.
So after learning the purposes and steps of creating different nodes, we can start to figure out how to place the nodes in a neat order to keep track of our adjustments. We can roughly categorise our graded nodes into the following categories:
Basic color-correction (and noise reduction, if necessary)
Secondary color-correction (subject-isolation - e.g. skin)
Secondary color-correction (partial adjustment excluding skin)
Next, we can categorise the similar nodes together. As we know Resolve arranges its nodes from left to right, we can place the similar nodes together from top to bottom to signify they are in the same group of adjustments.
Example 1. Basic node-tree organisation
I balanced the shot in node #2 and #3 to fix its color shift and luminosity. As we want to keep Leticia away from being affected, I separated her skin in node #4, so there won't be any overlapping adjustments on her skin in node #5 to #14. For example, the yellow-tint of the shelf was highlighted in node #10 to boost its contrast. As it shares the similar colour on Leticia's skin, this prevents making her skin looks punchy. Since we are dealing with such partial adjustments, I put node #5 to #14 together in one column to help signifying they are the specific adjustment. This is how the basic node tree is formed.
Example 2. Concise node-tree structure
The grading philosophy is similar, first from correction, followed by subject-isolation, partial adjustments, and global adjustment. We still have the same node structure for balancing, but in this case I placed two different node-columns to signify two partial adjustments. The left column deals with the green-pink tint and saturation of the background and the contrast/color-boost of the skin, and the right column specifically deals with the shadow of Ron's outfit and the near-white highlight in the image. So you may consider the first column adjusts the color of two sides of the background and the second one handles the look of the darkest and the brightest part of the image. We don't necessarily have to put all partial nodes together in one big column as we see in example one - nine adjustment nodes in a column can be quite confusing.
Of course, you can always label your nodes for a more intuitive grading experience. As you are more experienced in your grading journey, you may have a better philosophy of creating the look with less nodes - as we always say 'less is more'. This keeps the tree clean enough to avoid any confusion.
That's the basic idea of how node-tree is created to serve different purposes of your grade. Let me know if you have any questions, and I'll see you in the next blogpost!