malole wrote:

I managed to find some vintage purple carbon paper, which arrived today, and have been experimenting with different typewriters and different paper. The typewriters with harder older platens give the clearest results from the carbon paper, which isn't surprising really. I compared the purple of the carbon paper to the purple of my typewriter ribbon and it is quite different. In my opinion, the purple of the carbon paper is a deeper shade with more blue in it.
I've looked for references to vintage purple typewriter ribbon, and just can't find any mention of it anywhere.
 

 
I have a purplish ribbon for my smith Premier 4

There are several schools of thought here:  1.  I wouldn't recommend driveway patch because it is much softer than the rest of the platen, and you couldn't get it round enough--platens are precisely round.  The best thing to do is find a junker to see if there is another platen to repair the machine; 2.  You could contact J. J. Short to see how much it would be to resurface what you have.  It would be a bit more expensive, yes, but if you had the bucks (who among us does?); 3.  You could rewind those ribbons onto other spools of other machines you have.  Just because something is prewound on a particular spool doesn't mean that it's made for use only on that typewriter.  I've been rewinding ribbon spools for years, and I can tell you an Underwood ribbon will work just as well on a Royal--and vice versa--provided you wind it on the spools intended for the typewriter you're going to use.  So, if your repair isn't forthcoming as yet, you can always convert your ribbon stock for your other machines--half-inch ribbon is pretty universal--although I have seen some foreign machines using 9/16" ribbon.