Furthermore, every theater chain had their own house aperture plate size in which the picture was projected.

Aperture plate - is the gate removable for inspection and what accessories may it have?

At the theater, release prints are projected through an aperture plate, placed between the film and the projector's light source.

The aperture plate is placed just behind the gate, and masks off any light from hitting the image outside of the area intended to be shown.

An adjustable aperture plate was added to frame images that had been produced by a variety of cameras without any uniform standardization.

By using a different sized aperture plate and wider lens, a normal Academy ratio film could be matted to this or any other aspect ratio.

The Rubinar uses 2 milder such full aperture plates, being slightly shorter, lighter and ultimately better corrected, thanks to more decentering tolerance.

It included a special design for the aperture plate and projection of the picture through a double convexed spherical lens of lesser focal length.

Using a newly cut aperture plate in the movie projector, as well as a wider-angle lens, the film was exhibited in its first-run venues at an aspect ratio of 1.66:1.

Aspect ratios are controlled by the lens with the appropriate aperture plate, a piece of metal with a precisely cut rectangular hole in the middle of equivalent aspect ratio.

With the introduction of widescreen in the early 1950s, projectionists had to cope with the additional lenses, aperture plates and masking systems needed for different aspect ratios for the first time.

In this process, a fully exposed 1.37:1 Academy ratio-area is cropped in the projector to a wide-screen aspect ratio by the use of an aperture plate, also known as a soft matte.

Therefore, the nominal flange focal depth will be equivalent to the distance to the groundglass, whereas the actual flange focal depth to the aperture plate will in fact be 0.02 mm less.

The negative is shot exposing the Academy ratio using spherical lenses, but the top and bottom of the picture are hidden or masked off by a metal aperture plate, cut to specifications of the theater's screen, in the projector.

Alternatively, a hard matte in the printing or shooting stages may be used to mask off those areas while filming for composition purposes, but an aperture plate is still used to block off the appropriate areas in the theater.

Looking for a similar alternative, other major studios hit upon a simpler, less expensive solution by April 1953: using a removable aperture plate in the film projector gate, the top and bottom of the frame could be cropped to create a wider aspect ratio.

The aperture plate in combination with a prime lens of the appropriate focal distance determines which areas of the frame are magnified and projected and which are masked out, according to the aspect ratio in which the film is intended to be projected.

Some theaters have also used aperture plates that mask away part of the frame area that is supposed to be projected, usually where the screen is too small to accommodate a wider ratio and does not have a masking system in front of the screen itself.

In contrast, if the full frame is filled during filming and the projectionist is relied upon to matte out the top and bottom in the theater, it is referred to as a soft matte, as the aperture plate is not on the focal plane and causes a soft edge.