[Tig] fwd:Re: DI workflow, capabilities and requirements

Steve Shaw digital.praxis
Tue Mar 29 19:23:00 BST 2005

Just to clarify a few things as not everone seems to be understanding the workflow I'm suggesting - or rather using already - this is reality, not speculation...

At present offline is still going to be performed for most, if not all, projects, be they longform, commercials or music videos.

It's still not viable to transfer everything for immediate online use, and online systems tend to charge a lot more then offline. Will this ever change? Who knows - but I have my views.

However, grading for dailies/offline will change, with self-calibrating transfer engine, using LUT display technology, becoming more and more common.

The output format (not colourimetery) for the image data will vary depending on the job and the client's desires. But, the image information will be LOG transfers with LUT based display, if necessary witht the LUT burnt in to the video image.

However, more and more systems are imbedding LUT operation within themselves so this will become a normal approach.

I know Avid have only just realised that they need to offer HD 24fps input for offline, but I'm sure they won't be so slow with LUT display technology. And with everone using Cineon LOG format (dpx) all LUTs will calibrate to an equal, or at least acceptable, level. Much like one film lab's calibration vs anothers, at worse case (see later).

The recording format may be data to disc, but that's unlikely for dailies and offline, although we have done this with SBY. No tape used at all for the full 25TB of data, including offline and dailies.

It may be SR tape, but that's more of a high-end online format.

It may be D5, which is great for film dailies, as is HDcam, but probably too much for commercials intending to end up SD only. 

It may even be LOG data rcorded to digibeta.

The use of discs is really only for online work, when the offline edl will have been used to generate a pull-list to transfer only the required scenes, again in the same calibrated LOG format as the dailies/offline transfer.

I don't like any tape format for online as they are all compromised by compression. The SR deck is obviously the least compromised, but with discs so cheap, and with their cost being amortised over multiple projects unlike tape, why bother with tape? The only tape format I happily use is LTO2/3 for data backup and archive. But that's just me.

The resolution the online transfer happens at will be dictated by the final deliverable, and if it's no more then a SD commercial the original 'dailies' transfer may be acceptable, but I am now doing all my commercial work in HD for SD delivery, as a lot of clients are requesting this approach regardless of the final deliverable. SD dailies/offline for HD online resolution, for SD delivery. The quality benifit is obvious.

Neg cutting wont happen either as this is when more film damage happens than virtually anywhere else.

The full format LOG image data will then be conformed on-line, with vfx being done as required and the grade being performed with all material in context, using LUTs for image display and final video deliverable colourimetery, allowing full flexibility right up to the end.

The biggest issue, especially for DI work with a film deliverable requirement is the film lab's calibration and ability to hit AIM accurately.

On the Digital Praxis website there are three different examples of Marcie and McBeth images printed from the same source negative in the same lab over a period of time.

All prints were printed to AIM, all are different, and all are accurate to the lab's specifications... This is as good as chemical processing/printing gets. And it's not accurate enough for DI.


Steve Shaw
Digital Praxis Ltd.
+44(0)7765 400 908
steve at digitalpraxis.net

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