Guest Post: JK
This is part 4 of a 4 part series
This comparison uses estimated digital resolution equivalents of film to provide a baseline to compare quality of picture. These are based on recent movie restorations on each film format, the scan of the negative used on Interstellar, and personal judgement in seeing each of these formats projected in theaters.
- IMAX 7OMM Film: 11K digital equivalent
- 7OMM Film: 6K digital equivalent
- 35MM Film: 4K digital equivalent
IMAX 7OMM film is the highest resolution picture, followed by traditional 7Omm, 4K Digital formats, 35mm film, and finally, 2K Digital.
PICTURE COLOR REPRODUCTION
Largest to smallest color space:
- IMAX Laser 4K
- 4K Digital Laser
- IMAX 7OMM Film
- 7OMM Film
- 35MM Film
- 2K Digital, 4K Digital (In cases of early 4K projectors, 4K has less color representation than 2K projectors)
Aspect Ratio, or the ratio of width to height of the picture, is yet another consideration when either filming or projecting a movie. Most modern movies use either a ~1.8:1 or 2.35:1 ratio. Aspect ratio determines how wide or tall the screen will be, or how much of the picture you can see. In a traditional theater, a 2.35:1 ratio produces a wider picture, giving you 30% more of the image than a 1.85:1 projection, and almost double the picture of a 1.33:1 ratio of old “Full Screen” TVs. Standard 5/7OMM film is a 2.2:1 ratio, inbetween 1.8 and 2.35:1, but it is also used to hold other ratios.
Aspect Ratio of IMAX Film (15/70mm) and IMAX Laser 4K: IMAX Film and IMAX Laser 4K use a ratio of 1.4:1, which is more narrow than the other standards, but the screen is much, much taller, it provides the largest picture overall. The 1.4:1 ratio shows the same amount of picture as a 2.35:1, but almost doubles the height. Digital IMAX has a ratio similar to a standard ~1.8:1 ratio, so you don’t get to see near as much above and below the standard picture as in a full IMAX Film or IMAX Laser auditorium.
This is IMAX’s own comparison of IMAX Film to 35MM film - other than the scale, you can see how much more vertical picture there is on the IMAX film above batman and below his hand. This comparison holds true for IMAX Laser 4K compared to other digital formats.
SOUND WITH DIGITAL PROJECTION: Nearly all digital projection system use an uncompressed digital soundtrack, very similar to having full CD quality sound playing for every channel. Most common soundtracks are 5.1 and 7.1 surround. Dolby Atmos is a new type of theater sound which uses up to 64 different output channels of sound, that can include using speakers in the ceiling. Dolby Atmos is a system that uses a real-time processor tuned for that specific auditorium that calculates the which sounds are played on each speaker as the movie plays. Only select movies use this format, but it is becoming more common. IMAX digital sound has an edge on other digital theaters, except those with Dolby Atmos, since it has full range sound speakers - meaning every channel has a subwoofer as well as the higher pitched speakers full fuller and more impactful surround soundtracks.
1.) Comparison of scanned frames of IMAX 15/7O Film, 5/7OMM, and 35MM. Notice how IMAX picture has the perforations on the top and bottom instead of the sides, so that it will move through the projector horizontally.
2.) Same comparison, in photo form.
3.) Small rolls of 35mm and 7Omm film
4.) A small sample of an IMAX reel:
5.) Different Aspect Ratios represented on IMAX Film 15/7Omm. 2.35:1 is how most modern films would look on an IMAX screen. 1.4:1 is what a full IMAX frame of Dunkirk or other IMAX filmed scenes look like.
Part 4. tl;dr SO WHICH IS BEST? (At Least For Dunkirk)
More weight is placed on the picture quality than sound, as it is the largest differentiator for this movie.
Dunkirk has 3 sound mixes (order of descending quality):
12 Channel IMAX, 6 Channel IMAX, 5.1 Surround
Dunkirk is presented in 4 Aspect Ratios (order of largest amount of picture to least):
1.4:1 1.9:1 2.2:1 2.35:1