Cinematography Mailing List - CML

Ground Glass Ratio’s


Dear CML’ers,

Looks like I need some advice. I am in the process of having my Éclair ACL II converted to Super-16, and the technician that is doing the conversion suggested that I get a hold of the Shurco Tool company to re-etch my ground glass to my liking, as they do a very good job. The only problem is that I am not entirely sure what markings to have etched on my ground glass. I know that I would like as few markings as possible, so the viewfinder is not all cluttered up with lines and boxes. I plan on shooting a short film on Super-16 that I want to blow up to 35mm in the hopes of having a theatrical run at a few film festivals. My question is what set of lines should I have put on the ground glass, so that I am composing for proper theatrical projection? A 1.66 box? A 1.85 box? Do I need both boxes? In theory, TV of the future should be all 16x9 right, (yeah like that will ever happen in my lifetime) so do I really need the 4x3 TV safe box too? Anyway, any thoughts anyone may have on this would be greatly appreciated.

If you can, take a look at this adobe acrobat link. It has all of Shurco's templates. And there is another link with a new template of markings here as well:


Thanks again,
Carlo Besasie
Milwaukee, WI

The Super-16 frame is 1.688 : 1 and obviously you should have lines showing you this Full Aperture. I'd also have a 1.85 : 1 area marked inside that (or 1.78 : 1, i.e. 16:9, which is very close to 1.85, but not both probably.) So that's two aspect ratios marked (I shot a Super-16 feature once with only the Full Aperture markings and just guessed at 1.85 by leaving a little extra space above and below the subject and it looked fine in the 35mm 1.85 projection later -- but 1.85 lines would have been nice.)

If you're not going to compose for 4:3 centre extraction, but instead create a possible 4:3 pan & scan version later in the telecine, I wouldn't bother with a 4:3 box unless you plan on shooting a lot of 4:3 with the camera.

David Mullen
Cinematographer / L.A.

Hey Carlo,

I own a S16 Aaton with what I think is a great ground glass. It has Standard, super, and 1.78. + it has TV safe.

It is much akin to D:0181247 Aaton 7. The 1.78 is pretty close to 16:9 (14:9 I think)

One thing to think about is the possibility of st16 and making projection prints. Many say they have gone the way of the dodo...but I recently shot a project that required st16.

Also look at D:0181251 Scan 1.66 - 1.85 st16. Great ground glass...except that it has no TV safe.

You should have a ground glass that gives you options, yet is easy to navigate through the viewfinder.

All best,

Raoul Germain
Aaton Owner
Los Angeles

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