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Blending Emotion into Images using Composition Nodes
Image Processing using Composition Nodes
In this tutorial we will examine, step-by-step, many of the composition nodes and how they can be used to process a single image. Starting with a basic photo, we will examine and explain why and how each node helps us accomplish our mission. This tutorial is aimed at the intermediate user, who has read the User Manual and already knows how to set up the Node Editor for Composition, work with Nodes, set up the UV/Image Editor, and render images.
Getting Started
To get set up, create a dummy material and then a cloud texture called "Smoke" using your Buttons window. While in the Buttons window, select Do Composite in the Render settings Anim panel.
Split your screen and set one as a Node Editor, and the other as a UV/Image Editor. In a large Nodes Editor window header, select Composition Nodes by clicking the face icon, and click Use Nodes. Your Node Editor window should show a RenderLayer node and a Composite Node. In that window, press Space, LMB 
click Add, Input, Image node. Click on the Add New and pick an image from your hard drive of a person. LMB click Add, Input, Texture node and select the "Smoke" texture you created in the previous paragraph. LMB click Add, Ouput, Viewer to add a work-in-progress viewer. In the UV/Image Editor window, use the up-down arrow to select Viewer node. Now, when you click the Viewer node in the Node Editor, it's picture will show up in the UV/Image Editor window, much larger than otherwise available.
The following steps reveal, step-by-step, the noodle you will be making. Simply add and connect these nodes as shown. Notice that each node is connected to a Viewer node. When you click the viewer node, the image shows up in your UV/Image Editor window.
Global Possibilities
Please note that there are about as many ways to express thoughts and ideas through the graphic arts as there are graphic artists; actually probably more, since each artist has two or more styles that they like. So, what you like, I may not like, and vice versa. That's why having a customer is so important. If they like it, it's "done." Second, commonly accepted styles in graphics varies from country to country, culture to culture. So, what is considered aggressive and sexy in one country may be outlawed in another. Comic satire in one culture can invoke riots in another. I think you get the point. So, please don't take offense. Thank you.
Be Clear on Your Goal, and Save Your WIP
Have you even been asked to produce, in the words of a client, "I want something..oh I don't know...bold. And Fresh. Yes...I think." The best answer in this situation is to come back with 10 images and let them pick. Just be sure to save your node setup for each one, so that when they pick one and invariably say "Yes, just like this one, except..." you can go back to that node setup and build on your work in progress (WIP). You can waste a lot of time and incur a lot of frustration by having to re-create an image by starting from scratch. Sometimes minor adjustments to a color curve or mix setting has dramatic results not easily replicated. So, create a scene copy for each variation. Otherwise, anything you try to re-create will invariably result in the client saying "Oh, that wasn't it before..." (meaning the image they liked).
Be prepared for waffling from a client when you ask them to describe what they want; they don't have the vocabulary. Instead, ask them for examples, or similarities, or emotions they want to convey.
In our example, we want to convey the following scenario: a girl sees another girl wearing the outfit that she wishes she had bought.
List Your Thoughts
Whenever approaching an assignment, think about the tools you have at your disposal to communicate the idea through non-verbal means. In our example, we are only going to use Blender, so we only have all the Composition Nodes that do just about anything to an image, and we can model and light and render any virtual reality one can imagine. Ok, so no limits there.
Now it's just a simple matter of knowing what we want to convey, and how to convey it. Which is exactly why I wrote this tutorial. Read on.
If you think about the scenario, or brainstorm with a female (a glass of wine helps), the following emotions and thought fragments are what is going through her head:
- Envy: "Boy, I wish I had that outfit"
- Loathing: "I hate her for buying my outfit."
- Self-condemnation: "I should have bought it."
- Uncertainty: "Why didn't I buy it? Should I still buy it?"
- Anger, inward: "How could I have been so stupid and timid!?"
- Resolution: "Next time I am going to buy what I want."
- Fear: "What if I do buy it now, will I look stupid wearing the same thing?"
- Sadness: "I miss not having that outfit."
- Embarrassment: "OMG, I told my friend I was going to buy that outfit!"
- Being out Done: "She bought it before I did."
Map Thoughts to Non-Verbal Communication
In animation, much is conveyed through motion. The slightest shrug of the shoulders can convey uncertainty, nonchalance (uncaring attitude), or mild agreement. In our assignment, let's see how we translate these thoughts into graphic art effects:
- Envy: Saturate the Green hue, as in "Green with Envy", especially in the eyes.
- Uncertainty, Future in Doubt: Cloudy, hazy
- Confusion, Doubt: Blur, loss of focus.
- Anger, Resentment: Red, like Mars, the war planet.
- Resolution: Extreme contrast; heightened highs, lower lows. No in-between.
- Sadness: Darkness, especially overhead, tinges of blue, outlines in black (emo makeup)
- Embarrasment: blotchy, flushed, blushing
- Overshadowed: looks like you're standing in shadows under a tree.
- Outdone: moved off to the side, not centered in the picture
- Stressed: blotchy skin (red patches), flushed (redish-purplish tinge)
Boy, that's kind of depressing. Let's look at the opposite end of the emotional spectrum, including:
- Contentment: less contrast, no glare or patches of white on skin
- Happiness: Yellow, sunny
- Cold: blue tinge
- Hot: mirage effect above the object, as if you see the heat coming off it
- Sick: a yellowish greenish tinge, as jaundice sets in
- Busy: background blurred, usually more laterally (X) than vertical (Y)
- Dead: skin is white or gray
- Frozen: add a frost and/or mist layer. Desaturate colors.
- Hungry: Deep green surroundings. It is sed that a deep green or red actually makes people hungry.
- Calm: Blue surroundings.
In an image with people, pay particular attention to the eyes; they are "the windows into our soul".
You can also use the mask technique described in Manual/Compositing Blur the Background to separate the object under scrutiny from the background. You would want to do this to interject the Calm emotion by making the background more blue, and not the object. Adding blue to the object would just make it feel cold.
Using Nodes to Make our Point
So, we're going to use nodes that help us accomplish the graphical effects we want. We start with a stock photo, a girl looking off to the side. We introduce a cloud texture and use it to make it blotchy by using it as the factor to a Hue-Saturation node, doubling the saturation of the greens in certain places. Notice that immediately her eyes, which were white, become green with envy, since we doubled the saturation of that Hue.
Next, we run that "green with envy" WIP through a blur node. This adds the element of uncertainty, a loss of direction, and confusion. Literally, when we are a confused or lost, we say that "we lost focus". You will find that if you take many old sayings, and literally do that saying to the image, you will convey that emotion or feeling.
We also run the "green with envy" WIP to a mix node that has the Dodge settings, using the cloud texture (smoky haze) as the bottom input. This has the effect of darkening certain areas and lightening others, making the picture appear blotchy, more moody, as if she is standing in the shadows of a tree. With higher contrast and literally cloudy and uncertain, this node helps a lot. Did you know that people literally get blotches when they are under stress? Notice how she also looks flushed with the higher reds. Her lips are almost purple, like she is holding her breath in anticipation, and pursing them tightly.
We now combine the out of focus with the blotchy by mixing them, using the blotchy to lighten the fuzzy.
The result is not too bad, as it stands. It could be a little less blue maybe, to make her less purple, but so far, so good.
Congratulations! We have combined envy, uncertainty, embarrassment, and pensiveness all in to one single image.
Next up is one of my personal favorites; the Kirsch filter node. This baby wreaks havoc with contrast and color, posterizing an image. Notice that it is only set on 0.2! A setting of 1.0 results in a neon outline which I really love, just by itself. We use this node because we want you to feel like she is in the spotlight; she is in an uncomfortable situation; reality has slapped her in the face. This filter conveys all of that and more.
The Kirsh filter is way too powerful to use by itself, so we mix it with the WIP thread using a standard mix node. Adjust the factor to blend just enough of the Kirsh to bring out highlights in her har, face, lips, etc.
We run this composite through a final color adjustment node so she looks more like a human and less like a Smurf. This node has separate controls for each color channel as well as an overall control. I have replicated the node three times to show you its R, G, and B settings.
The Grand Finale
An artist is probably their biggest critic. In writing this, constantly fiddling, I found that I wanted the picture more moody; darker, to blend in the feeling of depression, sadness. So, I changed the last mix node to a Subtract, which, because it subtracted the high-contrast Kirsh filter, made all the highlights into darklights, making her look emo with black outlines around her lips, head, and features. Just the look I needed! Fiddling with the overall color control was needed to lighten the image, since we changed the previous node to subtract, not add the images together. Presto! We have a finished product:
Further Compositing
If this image was to be further layered onto a layout, or even if it was used by itself, I would use a Translate node to shift it to the left or right; probably to the right because she is looking left. Translating would convey the off-center, off-balance, on-the-sidelines feelings that she is experiencing right now. Shifting her farther away from where she is looking gives the feeling of being detached; shunned; not part of the group; ostracized; alone.
Conclusion
As a closing note, try to work in a quiet place and "Get in touch with your feelings, Luke" as Obi Wan said. I have also found that slight, teeny-tiny adjustments to the RBG Curves can have dramatic emotional effects. When compositing images for use in textbooks and magazines, subtlety is generally better than overtness; although comic art is all about "in-your-face" high contrast, high dynamic range colorization.
I hope this tutorial showed you how to use Compositing Nodes effectively, explaining exactly what they do and showing you their results in a practical setting. Above all, feel free to experiment, and check intermediate results after every change, because you just might find an unexpected surprise! Enjoy the wonders of Blender, and hope you can now use it a little more effectively.
