How do they make HD/Blu-ray movies?

I was saerching through Amazon the other day, where I saw some of my old favorites on sale. Then suddenly this question occurred to me: How are these old films available in wjde screen format? Take for example ‘The Omen’. Surely the technology was not there in those days? Then how do they convert these films into wide screen format? Do they cut and remove some portions from the film? I’ll greatly appreciate it if you could answer these questions. Thanks.

CinemaScope and VistaVision were popular in the 1950’s. Wide screen has been around a long time. There are examples that date back to the 1920’s.

This is not an area I know well, but I would imagine that the techniques used to convert the film to wide screen vary according to the aspect ratio used in the original movie.

Look at the current and previous aspect ratios used in film at this Wikipedia article:


Old movies and most new movies are shot in 35 mm wide negative film. Film negative is a very high resolving medium. Resolution in film is measured in cycles/mm (or line pairs per millimeter one pair consisting of one black line and one white line so one cycle (or one line pair ) could be said to be equivalent to 2 pixels, one black and on white) (It’s more complicated than that but that’s good enough for the example). Film by itself can commonly resolve from 50 c/mm to 400 c/mm (100 pixels/mm to 800 pixels/mm) depending on emulsion stock. But since the image on film is formed by exposing it through a lens and this lens also has it’s own resolution limits, the final resolution on the photographed negative is always less that each component’s resolution.

For example 70.7 c/mm (141.4 pixels per mm) for photographed fine grained film. Now to the film formats. Depending on the year and format a movie was made in, the image can vary on 35mm shot film from as big as 24mm x 36 mm for VistaVision/Technirama 8 perforation cameras (same as 35mm still photo film) going down through 18mm x 24mm for Silent Films or Full Frame 4 perforations cameras to as small as 9mm x 21mm in Academy Sound Aperture cameras modified for the Techniscope 2 perforation format. There’s also a few films made with bigger than 35mm cameras, like 70mm films (22mm x 48mm) and the couple of times used used 55mm and CINERAMA.

So multiplying the four mayor formats dimensions that have been used in 35mm by the pixels per millimeter gives you approx:

A) Academy Sound (Sound movies before 1955): 15mm x 21mm (1.375) = 2160 x 2970
B) Academy camera US Widescreen: 11mm x 21mm (1.85) = 1605 x 2970
C) Current Anamorphic Panavision ('Scope"): 17.5mm x 21mm (2.39) = 2485 x 2970
D) Super-35 for Anamorphic prints: 10mm x 24mm (2.39) = 1420 x 3390

In the process of making prints for exhibition this negative is copied onto other film (negative -> interpositive -> internegative -> print) so the resolution gets decimated with each emulsion copying step and when the image passes through a lens (for example, on a projector) it’s reduced once more. Sometimes the resolution is reduced down to 1/6th of the original negative’s resolution, and that’s with doing things correctly.

So depending on what film element is used for scanning and with what method, the resolution of the image used in the transfer from film can be from less than that of the 1080p x 1920 Blu-ray format to much more. If they use a properly stored and preserved original negative, the BD probably will end up looking better than what you might have seen elsewhere.