There are quite a few Instructables available describing creating your own custom vinyl decals, so I decided I would expand on that concept by introducing multi-color vinyl decals! The concept and application is fairly simple, but hopefully I can include some tips and tricks for using Adobe Illustrator that will assist your own designs.
Step 1: Choose Your Image(s)
I chose Pokemon Villain Team logos for my vinyl decals, since they're close to my heart and simple but elegant(-ish). To that end, I chose Team Magma and Team Rocket, since those were the teams in my favorite Pokemon games.
Step 2: Image Trace
Select your image, then Image Trace it; you'll want to select 3 Colors instead of [Default] this time, since our design is multiple colors! The default image trace creates a solid black block and removes the detail from the image. As usual, don't forget to Expand your image to create the vectors.
Step 3: Ungroup and Group
Image Trace outputs the vectors all as a Group, but we'll want to right-click andUngroup them to separate the parts of our design that will be colored and the parts that won't be. Then, using the Selection Tool, the black cursor (this is different from the Direct Selection Tool, which is a white cursor!), select the black/gray parts of the logo and right-click and re-Group these pieces together.
Note: If you can't see Group/Ungroup for whatever reason when you right-click, you can find them under Object -> Group.
Step 4: Move the Group
Move your group to a separate Artboard to organize them (you will be vinyl cutting them separately), and repeat the previous steps for the Team Rocket design! You should get something like the second image (I've arranged them to save space). Let me know if you have any problems with these steps!
Step 5: Change Colors
Adjust your colors to suit the vinyl cutter! In my case, our vinyl cutter takes black vectors, so I adjusted the line color to be black.
Step 6: Vinyl Cut and Weed
Once your design has been cut on the vinyl cutter (our makerspace has a Roland G-24), you'll have to weed your design. This is a the process of removing the excess vinyl that is not part of your final decal, and isolating your cut. Furthermore, apply transfer tape onto your design so that you can properly apply it.
Note: Use a card or flat surface to smooth out any bubbles that pop up when creating your decal! It does wonders for fixing the weird spaces that pop up.
Step 7: Apply and Align
To create multi-color decals, you just have to apply them consecutively! First place down your outer design, so you know where to place your inner design, then apply that one. Hopefully the images clearly indicate how to do this; aligning is simply a matter of understanding where the inner pieces should go, and carefully meeting the proper edges together. If you have any questions about this step, please let me know!
Step 8: Finished Product
Viola! There you go. Hopefully it looks a little more fun than just using one color for your vinyl decal; this technique can easily be applied to any color or design you'd like!
Note: I realized in retrospect that one option is to make the outer/back image solid, so that alignment is less of a headache (if, for example, you're slightly off, it's less visible!). I definitely had mixed results trying to align my decals, so I suggest you experiment with what looks best/is easiest for you to do. As always, let me know if you have any questions!