Finishing a 3D Render: Color Grading, Bloom, and Effects

A post production checklist for CG artists

Once you're done touching up your 3D render, the final phase of post-processing focuses on color grading and adding lens effects.

These instructions apply to 3D rendering in Photoshop, but the same techniques can be applied with GIMP, Lightroom, or any other graphic editing software.

Dial-In Your Contrast and Color Grading

Experiment to familiarize yourself with Photoshop's various adjustment layers (Brightness/Contrast, Levels, Curves, Hue/Saturation, Color Balance, etc.). Adjustment layers are non-destructive, so you should never be afraid to push things as far as possible. One of our favorite color-grading solutions is the gradient tool, which is an excellent way to add warm/cool color contrast and harmonize your color palette.

The gradient tool in Photoshop

Lightroom has a lot of options and presets for photographers that Photoshop doesn't give you access to. Likewise for Nuke and After Effects.

How to Add a Light Bloom Effect

The light bloom effect adds dramatic impact to a scene. It works well for interior shots with big windows, but the technique can really be extended to any scene where you really want little patches of light to jump off the screen.

  1. Create a duplicate of your render.

    Duplicate Layer in Photoshop
  2. Place it on the top layer of your composition, then go to Image > Adjustments > Levels.

    Go to Image > Adjustments > Levels in Photoshop.
  3. Drag both sliders to the left until the entire image is black except for the highlights.

    Output level sliders in Photoshop
  4. Change the layer mode to Overlay.

    Change the layer mode to Overlay.
  5. Go to Filter > Blur > Gaussian Blur and add some blur to the layer.

    Go to Filter > Blur > Gaussian Blur
  6. Adjust the layer Opacity to scale back the effect to your liking.

    Adjust the layer Opacity in Photoshop

Add Chromatic Abberation and Vignetting

Chromatic aberration and vignetting are forms of lens distortion that are produced by imperfections in real-world cameras and lenses. Because CG cameras have no imperfections, chromatic aberration and vignetting will not be present in a render unless you add them yourself.

It's a common mistake to go overboard on vignetting and chromatic aberration, but they can work wonders when used subtly. To create these effects in Photoshop, go to Filter > Lens Correction and play with the sliders until you achieve an effect you're happy with.

Lens Correction in Photoshop

Add Noise and Film Grain

Grain can give your image a very cinematic look and help sell your image as photorealistic. There are certain shots where noise or grain might be out of place, so if you're going for a super-clean look, this is something you may want to leave out.

Add Noise in Photoshop