Creating an old movie screen effect

Many games are set in different times. Some take place in fantasy worlds or future sci-fi worlds, and some even take place in the old west, where film cameras were just being developed and the movies that people watched were black and white or sometimes tinted with what is called a sepia effect. The look is very distinct, and we are going to replicate this look using a screen effect in Unity.

There are a few steps to achieve this look, and just to make the whole screen black and white or grayscale, we need to break down this effect into its component parts. If we analyze some reference footage of an old movie, we can begin to do this. Let's take a look at the following image and break down the elements that make up the old movie look:

We constructed this image using a few reference images found online. It is always a good idea to try and utilize Photoshop to construct images like this to aid you in creating a plan for your new screen effect. Performing this...