I recently was asked how I recreate broken, faded, or otherwise less than desirable plastics. I should state that I only reproduce plastics for myself and don't sell or redistribute them.
I start out with good quality scans of the original plastics at 300 dpi.
I then bring the scanned image into Photoshop and clean the image a bit. From this point forward I spend most of my time using the Pen tool to create the vector artwork. Learn how to use it. The Pen tool is your friend. There are many good tutorial videos and articles on the internet that show how to use it. Of course familiarity with Photoshop is a plus.
Using the Pen tool, I start out by creating outlines of the plastics and removing anything from the image outside of the plastics themselves. This includes removing anything between the printed artwork and the edges of the plastic.
I then select all of the black areas in the plastics using Select->Color Range, and convert that to a working path and then rename and save that path as "black". Then, using the Pen tool, I fix all of the areas that need adjustment (this can be time consuming) and finally create a new layer and fill the path with black. Here you can see the black shown with the plastic outlines.
Following this, I use (you guessed it) the Pen tool to create a path for the different colors. In areas where the color meets a black edge, you can be sloppy and let the red edges bleed into the black areas since the black layer will always be on top of any color layers. It's a simple matter of selecting the path in the dialog and filling that path with the correct color.
I continue this process for each of the colors, creating new layers as i go for each color.
After getting all of the color layers completed, using the Pen tool, I create paths for where the holes will be drilled.
This file could then be used to create silk screens, or with a vinyl printer (my method... it's way cheaper and looks quite nice). When the vinyl image has been applied to PETG, I use a scroll saw with a very fine blade to cut out the plastics and a drill press to drill the holes.
In the end, I have a very new set of looking plastics that look much better than the old originals. This is especially handy where reproductions are not available