I believe RocketScientist used what I used for my headlights. It's a chemical emulsion type of media.
A positive is created digitally. A laser printer prints the image onto plastic film. The plastic positive is used on top of the special emulsion media and a UV light is shown through the positive.
This is almost exactly like how an image is placed onto silk screen (T-shirts).
The vendor I used to have an emulsion media that was open and could be used with acid. Lack of sales meant he only carries the closed carrier that can only be used with sand blast. It might be available through other vendors.
An interesting DIY method I've seen lately is rubber stamp ink embossing. A special sticky ink is applied to a stamp. The item is stamped. A fine plastic media is sprinkled on and a specialty, small, direct heat gun is used to melt the plastic embossing to the surface. You've seen business cars use this method.
Now, instead of a stamp of the image, you do the reverse image. It would be like taking the GT350 letters out of your vinyl stripe so the car color shows through.
Dam off any other areas and apply your etch. When done remove the etch and scrape off the plastic.
It's a very cheap system.
I have not tried this.