8mm Forum: Variable Aperture Plates

This is topic Variable Aperture Plates in forum 16mm Forum at 8mm Forum.

To visit this topic, use this URL:
https://8mmforum.film-tech.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=5;t=001287

Posted by Paul Mason (Member # 4015) on June 04, 2015, 04:55 AM:

In the mid 1950s there was a certain amount of confusion in the film industry regarding picture aspect ratios. After Cinemascope was introduced in 1953, some cinemas masked the normal projector aperture plate to obtain projected pictures with width to height ratios of 1.6 to 2.0, saving the cost of the anamorphic lens but wasting part of the original film area and cropping off heads and feet from pre 1953 films.

Paramount's Vistavision was intended to be suitable for projector masking up to 2.0 by composing the shots with a large top and bottom safety margin but looked very "loose" when shown on pre-digital televisions or 1.37 (4:3) screen. Some films were shot with a "hard Matte" in the camera as they do today so a projector mask is unnecessary. I used to have a masked 16mm print of the 1959 MGM film "The Gazebo."

In 1957 GB Bell & Howell introduced a variable aperture back plate for the new 631 to 640 16mm projectors. This masked the picture down from 1.37 to a maximum of 2.0 and anything in between. This feature was continued in the 641 series but was omitted from the Japanese made models from the mid 60s onwards.

I was interested to know do members make use of this feature showing non-anamorphic films? Are other projectors fitted with anything similar?

Posted by Joel Whybrow (Member # 1377) on June 04, 2015, 09:37 AM:

This isn't really related to your topic so I apologise for immediately derailing the topic but I have wondered for a while if anyone masks flat 16mm prints as I had a print of Robocop 2 a while ago which was full frame but noticed when compared to the DVD version there was a fair bit more picture area on the print top and bottom. The DVD did have a bit more area on the sides but it really seemed that it should have been masked to achieve a more letterboxed picture.

Posted by Paul Mason (Member # 4015) on June 04, 2015, 10:36 AM:

Hi Joel
I think that 16mm prints were direct reductions from 35mm mostly, so would have had the same aspect ratio more or less. 35mm prints were shown on TV as well as cinemas so the same 4:3 prints could be shown on TV without masking (viewers objected to the "black bars" before the 1990S) but masked in the cinema to the letter box shape.

Posted by Maurice Leakey (Member # 916) on June 04, 2015, 10:55 AM:

My Bell & Howell 644 has a variable aperture plate although I never use it.

When I did mobile work in the 50s with a pre-war Bell & Howell 138 some 16mm prints varied from shot to shot, either full frame or wide-screen, i.e. black masking top and bottom.

When I complained to the G.B. Film Library (as they were then) they replied that I should have masked down my gate to wide-screen ratio and then all the film would have looked the same!

Posted by Alexander Vandeputte (Member # 1803) on June 04, 2015, 12:04 PM:

I don't have variable aperture plate, but I mask the image of some prints with tape on the projection window. Using a 25mm lens, I obtain a 1:1,66 aspect ratio on the screen which is perfect for me.
Some TV prints of features however cannot be masked as the image is a centre extraction of the 1,85 theatrical image.

Posted by Maurice Leakey (Member # 916) on June 04, 2015, 12:41 PM:

In the later years of 35mm film production, cinema prints were full frame for eventual showing on television.
The camera viewfinders were etched with two dotted lines to indicate that nothing important should be exposed outside the lines.
This way the print looked OK when viewed with 35mm projectors having wide screen aperture plates, and later, when shown on television the prints filled the TV screen and gave no indication of their wide screen heritage.

Posted by Dave Groves (Member # 4685) on June 04, 2015, 01:56 PM:

A good few years ago I had a B/H variable gate machine and masked it down to show 'The Robe' on a 12ft wide screen. Looked pretty good. Wished it had been included on the continuing models as it can be pretty useful to audiences more accustomed to a scope shape than 4x3.

Posted by Brian Fretwell (Member # 4302) on June 05, 2015, 04:24 AM:

I remember an early TV showing of The Blues Brothers (3:4) which showed that some shots were full frame and some slightly masked. I suspect different camera aperture plates. You never can tell what happens during production.

Posted by Paul Mason (Member # 4015) on June 06, 2015, 10:04 AM:

Thanks everyone for your thoughts. It seems that there are three basic forms of 35mm to 16mm reduction printing namely direct copying of the whole 35mm 4:3 frame, copying the central area of a widescreen frame and copying the whole 35mm widescreen frame so black bars appear top and bottom of the 16mm frame - even within the same film!

It does seem that the variable aperture gate was unique to Bell & Howell, perhaps because it was only useful occasionally.

Posted by Maurice Leakey (Member # 916) on June 06, 2015, 11:19 AM:

Regarding CinemaScope 35mm reduction to 16mm, there were three versions.
1) Full scope across the frame, leaving mighty deep black bars top and bottom.
2) Leaving titles squeezed, then the following film taken from centre of scope picture.
3) As 3) but following after titles with pan & scan from scope frame.
CinemaScope on 16mm was never very satisfactory owing to the extreme ratio compared with the original.

Posted by Paul Mason (Member # 4015) on June 06, 2015, 03:38 PM:

It does seem crazy to me that anamorphic "squeezed" films in Cinemascope or Panavision were available as flat "spherical" 16mm prints when 16mm projection with an anamorphic lens would be nearer the cinema experience.

UBB.classic^TM 6.3.1.2