Tech Tips by Leigh Ockey, Metro Screen Hire and Post Production Manager.
It has become inescapable: most cinemas require a DCP file to screen your film. Some may still accept BluRay or DVD (don’t – as it will look abysmal), but most film festivals will ask for a DCP. Here’s a few hints for making your film look its best in a cinema.
Firstly don’t make the DCP yourself unless you have done it before. Davinci Resolve and Premiere Pro have settings to export in DCP format, which can work. But it took us a long time to learn the intricacies of making DCPs and that meant a lot of failures. A LOT. Because of our relationship with Chauvel Cinema we were able to do test runs that meant finding out what doesn’t work and why. But don’t underestimate trial and error or you’ll find yourself at the 11th hour staring at a progress bar with 2 hours remaining because the last one wasn’t readable for no reason whatsoever. You don’t want the stress, you don’t want the failures, and you certainly don’t want your film to look really weird because something isn’t calibrated properly.
When you prepare a file for conversion to DCP make it as good as possible, but don’t be ridiculous. If you shot on an iPhone there’s not much point in exporting Uncompressed Quicktime. Export what is appropriate to how you shot. Which segways nicely into the next point.
Shoot For Cinema
The international standard framerate for DCP is 24fps. If you shoot and export 24 frames per second the film will be able to play anywhere. Not 23.976fps. Who knows what is going on in the US with their 1/1000 frame drop? Crazy yanks. Most cinemas in Australia, Europe and Asia can also play 25 frames per second. So unless you know you’ll need 25 frames for some distribution deal or you expect to screen on Australian Television, you are better off shooting in 24 frames per second and save the hassle of framerate conversion later.
2K for cinema is 1998 x 1080. Most HD cameras have a maximum resolution of 1920×1080. That means 39 pixels of black on the left and right side of your HD film. Which isn’t terrible if your film is a 16:9 ratio. If you then add a cinematic aspect ratio to your film by adding black letterboxing on the top and bottom what you end up with is your film as seen by Ned Kelly.
We see this sort of thing ALL THE TIME. But what would be worse is if a filmmaker took their 1920 x 817 (cropping the black) video and scaled it up to the full 2K scope size of 2048 x 858.
Don’t Scale Up
If you are only scaling your image a small amount you probably shouldn’t do it. You are effectively taking one whole pixel of information, smooshing it across (let’s say) 1.2 pixels, and then resolving it as just one pixel again. The result is a blurrier image because you’ve stretched the pixel and then cut it.
However, if your working resolution was greater than the number of pixels you are finishing in (perhaps 4K) you would be able to scale your image down to fit the 2K space and still have more resolution. So if you shot in a higher resolution than HD you will be able to export in either “scope” (2048 x 858) or any other size with a bit of letterboxing that fits into “full container” (2048 x 1080) and your film will cover the whole screen.
If you shoot in HD then you should keep a 16:9 ratio for the cinema screening to fill as much of the screen as possible. Or if that scope look is important to the storytelling you may have to weigh up the resolution loss from scaling up to 2K scope against the Ned Kelly look.
Davinci Resolve Lite is completely free! There are a few limitations for lite that are unlocked by paying for the license, but for most uses this is an incredibly powerful tool that costs nothing.
Colour Grading is an art form and the professionals are really good at what they do. If you do pay a colourist, provide reference images to demonstrate colour palette, and talk through the mood of each scene. The more precise you are when you start about the look, the easier it will be for them to start painting your vision.
If you choose to grade yourself, it’s a good idea to do a short course. The knowledge gained won’t just help you technically, but also to understand colour and how your manipulation of it takes effect. However, if you are jumping straight into a grade then begin with Colour Correction. Keep brightness consistent within a scene and make sure that your white balance is continuous. The most important thing is consistent skintones, but it’s a good idea to pick something within your scene, like a wall or the sky, and keep it looking the same across the scene. Once the shots are corrected you’ll have a level starting point for grading your look and feel.
We get the question occasionally about stereo sound being played in a cinema. Stereo is perfectly fine for screening when it is authored as Stereo. If stereo sound is converted to a 5.1 space all kinds of things go wrong. But stereo sound is normal and fills the room just fine.
If you do have the ability to do a 5.1 mix you should go for it. The difference of stereo to a surround sound mix is the creation of atmosphere and immersion. But this comes down to the skillful design of it. A mickey mouse surround mix is way worse than a good stereo one.
If you’re bringing a 5.1 mix for DCP conversion then make sure you have vision and sound in sync before exporting a video with no audio channels, and 6 mono audio files labeled correctly for track order (L, R, C, LFE, Ls, Rs) And please don’t have countdowns, IDs or pips. The ID is written into metadata, and while pips are great for syncing, when it comes to making a DCP it is easiest to just have content and remove the possibility of an unsettling beep resonating through the cinema.
Wherever possible, schedule with the cinema to test the DCP. There are all manner of things that can go wrong with DCP transport. Even blockbuster DCPs sent from Los Angeles on CRU drives can have hardware or formatting faults. So you want to be sure that the file loads with enough time to do the conversion again if it doesn’t.
If you are able to watch the film in the cinema you might see or hear something that you didn’t in the edit suite. There is a time at which you just have to let go and allow the film to be finished, but this might not be that moment. If possible, give yourself plenty of time to make changes by holding a test screening well in advance.
The best thing to do is to talk to a professional either from the cinema or someone who knows DCP. Most of the time the exhibitor will be able to send you a spec sheet with all manner of numbers and codecs to adhere to, but in the end all they really want from you is a file that will play without hassle. And of course, so do you.