Digital Intermediate has traditionally (as much as any concept as young as DI can have a tradition) been seen as a data centric workflow of high resolution images of 2K resolution or greater.

However, the benefits that Digital Intermediate workflow provides offers the chance to alter drastically the traditional approach to video post-production, while providing greater creative opportunities for the client with higher quality final results at a cost point equal to that of previous video based workflows.

In very simple terms the traditional approach for film captured material used for final video products has been to telecine the camera negative while grading to provide a usable 'video' image in readiness for the following on-line editing and vfx stages.

The DI approach by contrast is to 'clone' all the information contained within the film negative, often after having performed a previous 'one-light' telecine pass for the offline process and therefore use the offline edl to define the selected takes, with no grading taking place during the 'clone' transfer.

The benefits this offers - being able to grade the selected shots in-context of the final edit - is hard to state loudly enough. Grading should be performed towards the end of the process, not at the beginning.

Therefore, there is real interest in applying the DI approach to more traditional video post-production, especially as the use of HD increases as a final delivery format.

Obviously the main problem with a pure 'data centric' 2K DI workflow is that the facility performing the post work needs to invest in data networking and data based systems. And most data based operation run slower than video's real-time.

As a result HD infrastructure has been utilised in building a real-time DI approach to post-production. This can mean a number of different things, especially if the capture medium has been digital HD and not film, but looking at film captured projects provides an easy understanding of the process and benefits. Something that Soho boutique post-production facility AHC (see Light Illusion Client Base for additional info.) has taken to heart.

Rather than telecine as described above for video HD post-production (grading on the telecine) the film is transferred as a 10bit Log clone of the negative to HD tape in real-time. The best telecines for this at present are Cintel's DSX, C-Reality, Millennium and dataMill, and Thomson's Spirit 2, as they have self calibrating 10bit Log setup capability. This is something Light Illusion has consulted with Cintel about so we know the Cintel systems work!

The following diagram shows the Light Illusion approach to HD self-calibrated film scanning for DI workflow:

Although this 'data' is held with an HD video wrapper it is to all intents and purposes the same as 10bit log digital film data. The difference is that scanning takes place at real-time with the resulting data being recorded to 'video' tape, rather than a non real-time scan to disc. As a result costs are lower, especially as no colourist is involved in the telecine transfer as with a 'video' workflow. The telecine is being used as a real-time data scanner!

Within the DI post-production system the project is treated as for a full 'film' DI, with editing and vfx occurring prior to grading, resulting in a much better final image.

In time, all post-production will be done via a DI workflow.