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Cinema Projection Aspect Ratios

Contributed By Glen Berry

Cinema projection aspect ratios are quite different than the video aspect ratio. This means that the video image area must be cropped on the top and bottom to fill the projection screen. The entire video image can be shown in the projection area with no cropping by adding black to the sides of the image, which is called "letter boxing".

If the letter box technique is not utilized, cropping of the video frame will occur. Using the D-1 standard of 720 x 486, Standard Academy Camera Aperture will utilize 720 x 350 and Anamorphic Camera Aperture (a.k.a. Cinemascope, Panavision, and Widescreen) will only use 720 x 274. To avoid losing vital information, all logos and graphics must be kept in these areas. Normally, the image can be repositioned to favor the top or bottom of the image when cropping.

The following table shows various resolutions at the common aspect ratios. Though any resolution and pixel aspect can be used in digital effects, best results are obtained when proper attention is paid to maintaining correct aspect ratios for the desired film output.

Aspect Ratio 1K 2K 4K
Full Camera Aperture 1.33 1024 x 768 2048 x 1536 4096 x 3072
Academy Full Frame 1.37 914 x 666 1828 x 1332 3656 x 2664
Academy Projection 1.66 914 x 550 1828 x 1102 3656 x 2202
1.85 914 x 494 1828 x 988 3656 x 1976
Pre-squeezed image 1.18 914 x 774 1828 x 1550 3656 x 3098
UN squeezed image 2.35 914 x 388 1828 x 778 3656 x1556

By protecting for these respective areas, you can use the Full Camera Aperture file sizes in both Full and Academy aperture. Please note: It would be advisable to protect for the variation in projection aperture plates. Normally the aspect ratio is 1.85 but you should always protect for 1.66 for international projection practices.

Image aspect ratios can be a confusing issue when going to cinema release, so consult with transfer facility ahead of time with questions to be certain of the process.

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