2:1 Aperture Plates

[Jesse Crooks]

Last week I did an inventory of the 35mm parts in one of my booths and found a pair of 2:1 Flat aperture plates (Simplex part G-2302). They looked brand new (unfiled, still in the paper parts bag from Wolk) and I was curious why we had them. I checked the Simplex XL parts manual and found that they offered two Flat 2:1 plates and six Scope 2:1 plates.

The Scope plates could be for Superscope, but they're offered for both 4-track mag and optical, and I was under the impression that Superscope only used optical sound. And what on earth are the Flat 2:1 plates for?

Perhaps they're for theaters that cheated and ran both 1.85 and Scope on a 2:1 screen?

[Mark Gulbrandsen]

Oh, for sure for running scope on a flat or 2 to 1 screen. Had customers that actually thought that was fine to do. Also, Wolk did not always have every plate in stock, so you were shipped the next size under to what you could file to for your needs. I kept pinhole plates in my kit of parts.

[Jesse Crooks]

Are the Flat 2:1 plates also just used to cheat and run both formats on a 2:1 screen? Seems odd that we would have them... as far as I know our screens always had adjustable masking. Perhaps we inherited them from the previous operator, since everything else they did was a mess. I heard that when they twinned the theater in the 80s they just turned the two projectors from the center line of the old auditorium instead of moving them to the new center lines, and the guy who was renting the theater just before we took it over had installed XLs from a drive-in without retrofitting them for a downward tilt. But all the other items that I inventoried seem to have been purchased after we took over in the 90s. By the time I started we had the lenses and plates to run five different aspect ratios, so I thought perhaps there was a legitimate format that required the 2:1 plates.

[Steve Guttag]

I generally used the G-2302 plates for 1.85. If you look, Simplex's "U" plates are only undersized in width. That is fine if you have only vertical keystone to contend with or have perfect lenses to the screen height. Back in the day of singles and theatres with over 100-foot throws, it would have been easy enough for the projectionist to put up a target for the masking guy to put the drape across to perfectly fit the height. Such was not always the case in the era where I've grown up in. Often the screen is up before the projectors are ready to show film and you have what you have that was based on a perfect height/width.

Strong started shipping PR-1014 machines with four plates, the standard 1.85U, 2.39U and then the 2:1 for both flat and scope.

Most other projector companies for an "undersized" 1.85 would start the height somewhere between .400" and .420". Simplex didn't.

[Jesse Crooks]

Thanks, Steve!

[Jim Cassedy]

Like Mark, I kept a couple of 2:1 and pinhole plates in my "bag of tricks" because they were easy to file out to whatever size I needed. In fact, I don't know that I've actually ever ordered a "1:85" aperture plate. The experience I got from working mostly in older (pre 1960) theaters was that very few of them were built to "perfect" specifications. Especially those that were built before Cinemascope. There was almost always a bit of a compromise between the "ideal" throw distance, lens size or the idiosyncrasies of the old masking systems. So If I needed to replace an aperture plate, I'd order once size smaller (or 'blank' or 'pinhole' plate) and file it out to what I needed. I collected a wholdbuncha (mostly Century) aperture plates from theaters as they were trashing good equipment to put in digitalcinemastuff. So now I have a whole bag of assorted size plates and when I need one I can often find one that 'fits' just fine.

The person who might be able to add more to this topic is Sam Chavez- - he's one of the best aperture plate filers in the business. He can practically file plates with his eyes closed.

[Scott Norwood]

I once had to cut a 2.39:1 super-35 plate for a film production that was being shot locally. A 2:1 plate for a Century C was a good starting point for this, since the height is (if I remember correctly) slightly less than the 1.85 picture. In this particular case, it didn't need to be super-precise, anyway.