I am old enough to remember when you could buy a car with untinted windows. Tinted glass was an option on the W110 and good examples are hard to find.

But I have come across a front and rear window that are in almost perfect shape. But they came from a low end diesel and the original owner cheaped out to the point of not even buying a radio. This means a four speed and clear glass on all the windows.

So... Is there a process where the glass can be tinted to look like the original tinted glass? Not a film but more of a chemical process or a light green paint?

I seem to recall such a process from the 60's for those who bought a used car with clear glass and wanted it tinted. I can't find anyone doing this today.

Anyone know of such a service?

It isn't looking good

https://www.tintdude.com/forum/topic/67628-spray-on-window-tint/

spray on window tint - Hot Rod Forum : Hotrodders Bulletin Board

I'd have a look at house window companies or industrial targeted coating makers. 3M industrial side, as the automotive side might not have anything, would be a first choice. I'm thinking the market for cars is limited due to trying to spray it inside a car where the other markets deal with glass sitting on a bench.

Found some stuff that might work.

Sprayon spray paints | Window Tint Spray Paint

I'd be more inclined to drain the spray can and use a good auto body paint gun to get even coverage.

Krylon stained glass spray

The guy that owns this car currently has both windows out of the car. That is, his front and back windshield were cracked and he found good ones in two different wrecking yards. He then found they were both untinted and asked me, as an old guy, if I knew of any such process from the 60's.

I couldn't find a thing. I want to thank you for the research you did. I doubt that the guy I am working with is the only person who will never need this info.

Modern day films are pretty good and can be done with the glass in or out.
Biggest thing to worry about is to do with scratches on the glass .
My pick up was done 7 years ago and 300,000 kilometres later is still ok.
280 SLC is having new front and rear glass fitted and will be 'filmed' straight after fitting.
Forget the spray cans.