Sunday 12 February 2006

What's all the fuss on DI resolution?

It's been over 3 weeks since I posted. Just what I feared the most about maintaining a blog.

Anyway, while speaking to a film director the other day a colleague mentioned that there was no point doing a film digital post-production (called Digital Intermediate or DI) at a resolution of 4k because with conventional means when one finishes a film optically, one has a print that has a resolution of barely '1k'. The Director was aghast and I was apalled at this comment.

Later I discussed this with the DOP (Dir of Photography, or Cinematographer) of this forthcoming film. I explained that there is no real inherent resolution of 35 mm film that can be expressed as pixels, since it is an analog medium. It is generally assumed that scanning a film at '2k' or 2048x1556 yields a digital picture that captures all that the film 'contains'.

The later digital correction and compositing stages do not reduce this resolution like the conventional optical process can - the act of making prints or dupe negatives. So going digital may induce some losses at the initial conversion stage, but further work does not add losses.

And incidentally, on projection, '1k' doesn't look sharp enough, while '4k' doesn't seem to look vastly better than '2k'. In part because we don't really have any viable 4k projector or monitor yet.

Further, to put this '2k' and '4k' thing into perspective, I mentioned to this DOP that 2k while seeming like a lot, isn't much when you consider that it amounts to '3 megapixels'. And most any cheap digital camera can match that. And now, 5 and even 8 megapixel cameras are getting quite common. Even mobile phones have 1-2 megapixel cameras - which is nearly the resolution of HD. Suddenly HD which stands for 'High Definition' seems puny. Right?

Well, not quite.

While digital cameras can easily do 3 Megapixels or 2k, they cannot do it 24 times each second. And even if they did, they would run out of memory in seconds. They store images on memory cards, maybe a hundred to a thousand images to a card. Film digital post needs 24 each second, 1440 each minute and 86400 each hour of shooting. And all these images have to be uncompressed, not jpeg. And they have to be held securely for as many months as the post production takes. A tall order.

But when you come to think of that, this storage and access is the current bottle-neck in the progress of truly digital cinema. By digital cinema I mean 'filming', storing, editing, finishing, and releasing digitally. At full resolution, uncompressed, with full 16-bit (sort of like 16 stops) latitude, just like 35 mm film can do right here right now. And hey, HD does not come close to this, yet. Probably never will. I mean, just look at a 2k image projected on a large screen side by side to an HD image and you'll know what I mean.

It was a scant 3-5 years ago that people spoke the same about still photography going digital. They said, it didn't have the latitude, how would you store images, how would you process them? etc etc. And now, we have very few photographers, even pros, fashion and industrial photographers using still cameras with 35 mm film. I too have my Canon A-1 with a variety of lenses, locked up in a cupboard.

So it looks lik a matter of time before film will be truly dead. Which it surely will, but nowhere near when it was supposed to be. Like in 1986 when I first heard this 'film is dead' thing when U-matic machines were introduced for TV production. Seems really funny now. Its 2006 and film is still doing roaring business - in India at least.

But finally, when film is really dead, along with it will go the film scanners, the conforming and grading systems, colour management systems, processing labs, and all that paraphernalia. Don't count on it happening in 2006 though. I would say the process will be probably start by 2010 and happen gradually till 2015.

Just in case this word Digital Intermediate or its short form DI has you wondering, head over to my DI pages, the link to which is in the margin to the right 'My DI pages'. Or you can go here
www.sadwelkar.com/DI.htm
you may have to copy and paste this link in your browser.

1 comment:

  1. Dev Benegal7:11 PM

    Neil,

    I imagine the DoP meant that after the Indian labs have done there bit on on your negative they deliver a lower than 1k print to you!
    I'm almost with the DoP given the abysmal quality of processing, handling, developing, printing and so on. It's a miracle the print looks anywhere near decent and the negative lasts more than a few years.

    ReplyDelete

Place your comment on what I have written here. If you want to ask a a question or expect a response from me consider mailing me. My address is linked in the margin.

If its advice for a commercial project, I may expect to be compensated for a response.