Rendering and Compositing - Blender Master Class: A Hands-on Guide to Modeling, Sculpting, Materials, and Rendering - page 238

The Color Balance node has three sets of con-
trols, each of which sets an RGB color. You can set
each input by using the color wheel to control the
hue and saturation and using the vertical slider
to control the color. The color you select is shown
below in the color picker. You can also click the
color picker to use Blender's default color picker
or to set RGB or HSV values manually.
The Color Balance node inputs are named lift ,
gamma , and gain , and they can be thought of as
affecting the shadows, midtones, and highlights of
an image. Thus, to give an image less prominent
highlights, you could turn down the brightness of
the lift input. To give it saturated red highlights,
you could set the gain color toward red. In general,
setting opposing colors for the lift and gain inputs
often results in an image with nice color harmonies
between the lights and darks.
In many Hollywood movies, the shadows are
teal or blue, while the midtones and highlights are
pushed toward orange—a color scheme that works
well with the pinkish-orange of most lighter skin
tones. For the Bat Creature, I opted for a slightly
blue lift color and a slightly yellow gain color. The
effect is shown in Figure 14-8.

Adding a Vignette
Next, I added a vignette to my image to slightly
darken its corners and draw the viewer's attention
to the center of the frame. To create this effect, I
took the alpha channel of my body layer and ran it
thought a lens distortion filter with a distort value
of 1. This distorted the image into a circular shape
with black corners, which was almost what I needed.
Then, I used a Blur node set to Fast Gaussian
Blur with a relative radius of 50 percent to blur the
output of the Lens Distortion node. This gave the
image a soft gradient out from the middle, which I
then overlaid onto the color-corrected render.
Finally, I added a Sharpen node with a very low
Factor setting (around 0.05) to the end of the node
tree and connected the output to the Composite
node. The final node tree is shown in Figure 14-9,
and the result is shown in Figure 14-10.

Compositing Feedback and Viewer Nodes
Creating a final composite from your renders can be
a long process that requires some experimentation.
To aid in the process, Blender automatically recom-
posites your final render when you change the node
tree. An alternative way to get a feel for how your
node setup is working is to use the Viewer node, a
secondary output node that lets you view any stage
in your node tree.

Figure 14-8: Adding color grading to the render of the Bat Creature. Left: Before grading. Middle: The Color Balance node.
Right: After grading.