Blender 2.8+ Old-Render Compositing Guide

In this guide, you'll be learning how to composite Blender renders to have a similar visual style to that of 90s CGI renders.

NOTE:

Intermediate users only.

Step 1

The first thing you're going to want to do is render out a scene. For this guide I've made a scene of a few primitives of various colors. The best way for an old-feeling look is using the Non-Principled BSDF from Render96 (link in resources page), set the world to black, and use simple lighting.



Step 2

For the next step, you're going to want to start the compositing. Renders from that time period (the 90s) were made on dated hardware that couldn't handle as many colors. We are going to be emulating this by limiting the colors to a 24-color depth in the compositor.




To do this, add a "Separate to RGBA" node next to the Render Layers node, and plug the image into the image of the Separate RGBA.

Then, add a Color Ramp node. You're going to be making three of these, one for each channel, but just make one for now and copy it for the other two. You're going to be adding a new point at every 0.041667th position 23 times. Set the Interpolation from Linear to Constant, to get it to be a hard transition between colors. Your end result gradient should look like the one in the image.

After this, you're going to duplicate the Color Ramp twice. Then, add a "Combine RGBA" node, and put it to the right of all the color ramps. You're going to plug each channel in the Separate RGBA node into its respective Color Ramp, then plug the Image output of each color ramp back into the same channel in the Combine RGBA node. (Gif added for visual aid.)



Finally, plug the Combine RGBA node into the Compositie node, and you're done! Your image should now look like this:



Step 3

Now! You might have noticed that that result is a little bit darker than the original render. That is completely intentional! The decrease in color depth means that more color will show as dark, due to the fact that there are more shades than highlights.

This is an easy fix! Add a Brightness/Contrast node inbetween the Separate RGBA and Render Layers nodes, and increase the brightness/contrast until it fits the original image.

Ontop of this, you'll also notice right after that the colors are now too saturated. To balance this,





Add a Hue/Saturation/Value node next to the Brightness node, and decrease the saturation until it looks close enough to the original.







Step 4

This part might be a little bit complicated, which is why I added the note at the top of the page. I won't be explaining how everything works here, but do your best to follow along.

This will add a little bit of surrealism to your render, making it look less raw.

First off, add a Texture node, and generate a noise in it. Alternatively, generate noise in an external program, add an Image node, input the noise, and use that instead.

Then, you're going to add a mix node inbetween the Saturation and Separate RGBA node. Plug the original render into the first color, and the noise texture into the second. Adjust the factor to your liking.

After that, add a Blur node and put it after the mix node. Plug the result of the Mix node into the blur's Image input. Set the blur's mode to Fast Gaussian, set it to Relative, and set the X and Y percentages to 0.5%.

Then you will be adding another mix node after the Blur. Plug the blur into the bottom input on the mix, and the original mix into the top input. Finally, put the result of this mix node into the Separate RGBA node.

Your result should look like this:



That's essentially it! There are other things you can add like dithering to date it even further back, but these are the techniques you could use to make it look more authentic.