2K Film Resolution


#1

Hi,

I keep hearing about film format being “2K resolution” but could anyone help clarify for me how does this translate to pixels? I am a Maya newbie, but I am interested in making a 3D animated short film which I can play at festivals, also I simply want to get used to producing film resolution renders since my interest is mainly to work in 3D for the feature film industry.

A few film-related websites say that 2K is 2048 x 1536 but that doesn’t seem right since the aspect ratio would then be 4:3 (television) instead of the 1:1.85 or 1:2.35 used for film. Furthermore the render globals on Maya has a “2K” (as well as 3K and 4K) option which produces a 2048 x 2048 square, so that begs the question is it done this way and then cut down later into the appropriate aspect ratio?

Is there anyone who knows the industry standards for how 3D output for film is handled?

Additionally, Leigh van der Byl mentioned in one of her tutorials on this site that calculation of image size for texturing should be based on final output resolution x 2, but my question is, does this hold up for extreme closeup shots for example zooming in on my character’s lips or eye? or do I need to anticipate using extreme closeups and make a larger map?

Basically I’ve made a few practice models, and now I want to go for making a proper head model which will holdup its photorealism under extreme closeups.

All insight and participation welcome, cheers!


#2

Film, that’s 35mm or 16mm (or good old hardcore 8mm) is 4:3, BUT, the aspect ratio you mention should have given you a clue already…Film usually uses anamorphic screens (they record on 4:3 material using a lens that squeezes the shot material in width, when projecting it back on screen it gets stretched again to restore the original ratio)

So, 2K is the scanned film’s resolution (meaning you get background plates that are around 2000 pixels), but it doesn’t necessarily mean your pixel aspect ratio (and thus the projected film size) is square pixel.

As for textures, you can get away with a little underscaling of textures, but you don’t want to push it, so yes, you do make higher res material for close ups…

edit

Usually i would have scolded you for not searching on the net but, here are some links for you (3D is based on the normal world, same goes for film sizes, so you can always deduce from where it came by just doing some research)

Aspect Ratios

Film Formats

More than one hundred years of Film Sizes

How Film Is Transferred to Video


#3

Well not all film frmats are squeezed. Some of them they just crop the top and bottom to get the proper aspect ratio. Anyway a good place to find all that info is the Art and Science of Digital Compositing book by Brinkman, it specifies many of the film formats.

As far as texures it depends. For extreme closeup x 2 might not be enough. It just depends on how close you get. The other solution is to use a procedural texture controlledby texture maps. Something like a RMan renderer has good filtering and having a procedural texture can alleviate some of those problems. Best way to determine is to do tests, render a frame at the closes point and see if the texture holds up.


#4

thats why if you watch the making of movie shows you can see boom mics in the shot sometimes (if they show the original dailys and not the low res avid output) because if they didnt shoot with an animorphic lens they have to crop the shot to make it fit.

If you happen to see any of the raw shots from T2 you will see it’s especially noticable as cameron shot in 72mm which is even more square, so, they shoot with markers on the lens to see where it would be cropped so they can compose the shot right and get the boom mic right to the edge of the frame.

You can set Maya to render animorphic too…for instance when you render CCIR 601 for NTSC it is slightly squashed, because it uses a different pixel set for TV…when you render 2k animorphic (there should be a setting like that) it should squash the frame.

There really isnt a reason to “practice” this though…the only difference would be that you would be wasting more of your comps resources working on really high res textures and renders for no reason…you can work at ntsc res and gain just as much knowledge and skill (actually more, cuz you wont be waiting as much!)

only work at 2k res if you have a reason to…its too much of a pain in the ass to use as practice and all you will get out of it is a headache.


#5

…thanks for the informative History of Film links, but none of them seem to address the specific issue of going from 3D to film. NTSC, PAL, and HD are pretty clear - but film not.

Part of the reason I posted here was because my search on the internet left me more confused the more I read, because just like the three responses received so far - EVERYONE SEEMS TO BE SAYING DIFFERENT THINGS! Auughh!

That’s fine because so far it’s all very helpful in me crafting my own answer, but does anyone have any specific insight as to what resolution I should render if I plan to print my animation onto film for film festivals? Or simply insight into the process of going from inside my Maya workspace onto the silver screen?


#6

#7

The 2048 x 1556 preset is generally speaking correct, as this is close to what most film transfer houses want to see (so they can work on it further).

Be aware that there are different formats on exactly what the active area of the film frame is, so that rule above bears some modifications depending on whether you use the Full Aperture (the whole area of the film strip, including the sound track area) or the Academy Aperture (where the sound track area is masked on the left side). The Academy Aperture is obviously what usually gets printed and it has an aspect ration of 1.37:1 or translated in terms of pixels: 2048 x 1492.

Now about the actual resolution you render at, it depends on how you want to frame your shots, as the people above already explained. The common standard for the so called “flat” films is 1.85:1 (pretty close actually to 16:9). However, the actual image area is still “4:3”, just with hard-matted black bars on the top and bottom.

Bearing in mind that for showing these flat films projectionists have to use a form of matting in the projector as well, you can imagine that it presents some alignment problems which could in the more extreme cases result in the showing of your precious new film misaligned either upwards or downwards by quite a lot, showing black on top or on the bottom if there is no content in that area.

That’s why a compromise is usually made: render at an aspect ratio of 1.66:1 to shave off some render time AND to still have a good error margin area in case of misframed projection. In short, that means rendering at something like 1828x 1101 (1828 comes from the fact that you want to take into account the aforementioned aperture/soundtrack problem, and 1101 from the aspect ratio) to get that desired 1.66:1 frame (however, always remember to design your composition for 1.85:1). If you feel courageous, you can also render directly at a 1.85:1 ratio by using 1828 x 988 (same explanation).

If you go for that widescreen look, you should aim for 2.35:1 (actually 2.39, and yes, there are so many SMPTE standards about that, you get a headache…). That one is achieved not by adding a matte on your image, but rather by rendering it “squeezed” in a (roughly speaking) 4:3 frame, which is usually for transfers taken to be 1828 x 1556 (with 2:1 pixel aspect ratio - your rendering software should have an option for that).

There is another 2.35:1 35 mm standard (but not really used for projection) called Super 35, which uses a wider area of the whole film strip and doesn’t require the anamorphic squeezing, so the resolution for that is 2048 x 872 (since it is used mostly for shooting film, it doesn’t have a soundtrack area to worry about). Don’t go there, as there is no practical use for what you want to do and there are also 2 very different standards on how to position the image (common top/center frame).

However, talk to the film recording house beforehand about all this (they usually have a brochure or a technical contact person which you can ask). Let me repeat that: talk to them, as you will either save some processing costs (if they charge setup fees) or you will avoid embarassing cropping or bad positioning of your image in the final print.

Hope this helped,
Andrei


#8

3D elements often look better on film if they are rendered at a lower res, then scaled up, because gets rid of any hard edges that might make them stand out as CG.

VFX facilities often have a higher resolution for scaning/recording film (maybe 2048 or usually a little higher) but render 3D elements at a lower resolution (maybe about 1800 across) that get scaled up and filtered a bit before they are comped with the film.

-jeremy


#9

Thanks, that’s a lot of really quality information.

Nitpicky question for Amyd (or any else who has an answer): you suggested rendering it at 4:3 but composing it for 1.85…not sure if you’re a Maya user but how do you suggest doing that, specifically?

Maya makes a resolution gate which appears in the camera view so you can compose renders, but it does that for the resolution at which it will be rendered. I suppose I could set the render globals for a customized 1.85 ratio so I get the resolution gate for composing and then switch the render to 4:3 (keeping the same resolution width and without moving the camera) just before the actual render - but maybe more experienced users have a more practical solution (like creating a camera with a customized image plane?) which doesn’t involve constantly switching the render parameters.


#10

No, if you read more carefully I suggested rendering at 1.66:1 but framing for 1.85:1 or rendering directly at 1.85:1.

If you do it like that, you can probably deliver it to the film recording house just as-is and they’ll position it properly (of course, if you point out in the request form what format you used). If they ask you to give them “4:3” frames, you can add the top and bottom black bars in a compositing program more easily than in Maya, I think.

I am not a Maya user (hmm, actually I was for a couple of weeks while I played around with our new copy - but I am not a 3D guy), however I cannot imagine you cannot do it something like this:

  • choose 1.66:1 as the render aspect ration (or 1.37:1 if you must) and then define something which should be called “Title Safe Area” or “View Safe Area” or so on to be at 0% left and right (to fill the whole frame horizontally) and at 12% top and bottom (for 1.66:1) to achieve the guidelines for framing at 1.85:1 while you work in the viewports.

Maybe someone with Maya chops can give you an even better solution.

Btw. something I forgot to mention in my original message: you realise that the frame format and pixel resolution is just the beginning of your problems when it comes to printing to film, right? Cause there is a whole other world of issues when it comes to bit resolution, color spaces, latitude and so on…

Cheers,
Andrei


#11

Originally posted by jeremybirn
[B]3D elements often look better on film if they are rendered at a lower res, then scaled up, because gets rid of any hard edges that might make them stand out as CG.

VFX facilities often have a higher resolution for scaning/recording film (maybe 2048 or usually a little higher) but render 3D elements at a lower resolution (maybe about 1800 across) that get scaled up and filtered a bit before they are comped with the film.

-jeremy [/B]

Hi Jeremy,
Interesting, this is the first time I’ve heard this suggested. I know that CG stuff is usually (always?) blurred to get rid of the edges as you said, but I wasn’t aware that people scaled them up…

I assume that the reason for this is that if you’ve already decided that you’re going to blur it, then there’s no point rendering at full resolution because it won’t affect the final (blurred) image anyway, and it saves you render time…

Your figures indicated a 10% scale change, so that would be about 20% less pixels to render, so 25% more work done in the same time… Makes sense.

BTW, liked your book - consider ‘ambient’ light banished forever!

Cheers - Steve


#12

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