How about Rubylith? Astronomers use it to filter out non-red light from their laptops. There's a bloke selling it cheap on eBay.

It's awesome stuff! And I take a weird kind of delight when people discover a new use for a thing that's been around for decades.

Well, I told the Rubylith guy why there was suddenly so much interest. He wants to make some pre-cut-to-size pieces for us - looks like he'd be charging basically buttons. Here's his response:

"Thanks for the information -- yes, we've been curious what was behind the sudden popularity. Wow . . . Pinball Machines, eh? I could not have imagined that!

We were surprised by more than just the high number of orders. It was also the large sizes ordered. 11" x 14" is not the most popular. Astronomers usually just want enough to cover an iPad or Android phone . . . maybe headlights. And usually the only foreign country we ship to, is Australia. This time, it's been two to Canada and one each to Norway and Russia.

Whenever there is a new interest in Rubylith, I usually like to write up several paragraphs about it because the new folk don't know anything about what it was originally used for. I'm an old-time stripper from the 1970's [No not THAT kind of stripper . . . get your head out of the gutter!] But to describe to you how Rubylith works, will take several paragraphs. Sometimes my messages are interesting enough, they get re-posted on other people's Blogs.

But eBay has a limit on how many characters per message. So I'd like to communicate by e-mail or some website, but eBay also has a "word-eater" which censors references to eMail addresses and URLs. This might get through; read it backwards: moctodloata3105resu

What I'll tell you quickly in this message is that I sell various sizes which are standard in the Lithography (printing) business. But my original stock is much bigger than 11" x 14". My original sheets are 30" x 40", which I then cut to size.

If you folk want, I can custom cut from that to any size you need. Now, I won't pull out my French curves for this (it would most likely be inaccurate anyway). But I can easily cut large rectangles, triangles, or even simple trapezoids.

The price I would charge is about 2 1/2¢ per square inch -- actually, it is $0.023125 per square inch, with the total rounded to the nearest dime. I make a decent profit on that, so I would charge the same for the bigger pieces. Since I have to cut them to size on eve"

Yeah, eBay word-eated him a bit - but it certainly looks like he's interested in cutting custom sizes for pinball DMD filters. I responded with:

"I think that'd be neat! Would you mind if I posted this message to the pinside forum?"

And he came back with:

"Wonderful! Yes, please post.

As you can see, eBay's Word-Eater, censored my eMail address. My last communication also got cut off after 2,000 characters.

I have listed a "Custom Cut Size" sale on eBay. Search for item #390759526686.

I have never done this before, so I'm making it up as I go along. If anyone has problems, kind feedback would be appreciated. I can revise my sale on-the-fly, to correct most anything that goes wrong with a sale.

I would like to write more, but a 2,000 character limit is a problem. Some other avenue of contact is desirable. This will do for now.

Hope this helps,
Jay Toser"

I told him how to find the thread in a roundabout, searchy kind of way (I think eBay might have eaten my first link) so maybe he'll drop by and take a look.

Ivan/Jay, they're not ordering Rubylith for the entire backglass - just for the dot matrix display (abbreviated to DMD). It's the orange-coloured display at the bottom of the backglass, where scores and such are displayed (for avoidance of doubt, the portion shown in the most recent photo that is currently displaying "Free play / push start" and "Start 4 non-claw modes for Huxley").