I have a black leather-grain guitar case made of something synthetic -- perhaps vinyl.

What can I use to write on it that will be both visible and permanent? If the case were a light color, I could use a permanent marker, but it's black, so the simple option is out.

Putting on a lighter sticker of some kind is a possibility, but the leather grain is probably deep enough to defeat stickers, possibly excepting duct tape.

White paint-markers? Followed by a little spray-on fixative?

The ever popular stencil and spray-paint?

Yeah, you can buy the silver or gold magic marker, but they are not really permanent. Your best bet is a paint marker and fixative. Or a branding iron.

Nail polish.......

Sharpie makes a bunch of colours to choose from...

right. but even the industrial brand wears right off of surfaces that get a lot of rubbing. I have a half-dozen of the silver ones. Great for dark material that doesn't get a lot of wear, use it for cable labels on shows with black duct tape. Tried labeling tool handles and plastic handles, case sides, no go.

Enamel spray paint and stencils or a brush & a solvent-based paint are the way to go, if you have the drawing chops to make it look good. It melts into the plastic and becomes part of it. No rubbing off after that.

I say brand that sucker - gretsch style!

Look for something like Markal that is designed for permanent marking on steel and other metals. I think it's some kind of enamel paint in a ball point type marker pen.

"Look for something like Markal that is designed for permanent marking on steel and other metals. I think it's some kind of enamel paint in a ball point type marker pen."

That is what we are talking about when we say 'paint marker'. Generically, ask for a paint marker and you'll get a Markal or some other brand of the same thing

Haven't had a lot of luck with anything like that though. Since the OP was 'scribbling' I think that we are all looking for some means of actually scribbling. Meanwhile, as has been mentioned above, stencils and spray paint is the traditional tried and true method.

Thanks for the advice, guys.

The idea of branding the case is interesting, but I'm worried I might simply burn through the outer cover completely. I'll look into getting some stencils and spray paint.