It's easy to understand the problems that are being experienced by many DoP and Studios, with digital dailies not representing the actual colour, contrast or mood of the image shot on-set, but it's a struggle to understand why these image errors are being allowed to happen in the first place.

It is eminently possible to provide digital (HD or otherwise) dailies that are as accurate as film prints to the underlying captured image present on the negative, with the following DI process being just as accurate through it's use of the basic image data.

The problem seems to be that not enough people involved in the digital dailies and DI process yet understand the very simple workflow required to make this a totally accurate methodology for total colour control and calibration, and instead dailies are being creatively graded by telecine colourists, when that is in actuality the last thing that should be being done. Even telling a telecine colourist to 'grade in the middle' or 'perform a technical grade' or to 'do a one light' offers no guarantee that the resultant digital image will be anything like what the DoP actually shot, as I'm sure most DoPs can attest too.

This is because the creative process of telecine grading relies on the colourist to control a system that has no guaranteed datum point referencing the image actually contained on the original film. In basic terms telecines are not 'calibrated'. It's what a telecine suite exists for after all - producing an image that is pleasing to the eye, regardless of the underlying image information contained on the film being transferred.

However, there is a very simple process that can be applied to digital dailies, and the ensuing DI process, that ensures the digital image seen is always faithful to that captured by the DoP on-set.

Rather than using a telecine as a creative tool, it should be used to transfer an image via a fixed relationship between the film density and the digital data.

This we have all been doing for years with film scanners, which transfer images based on Kodak's Cineon film density transfer characteristics, generating a known digital image file that represents the underlying film image very accurately, effectively creating a clone of the OCN. This image, usually a 10bit LOG DPX image, can then be shown via a calibrated LUT to present a very accurate 'preview' of the film image when printed. In fact, so accurate that the problem then becomes ensuring the film processing lab can print and process as accurately as the calibrated LOG digital film transfer and LUT presented image.

The one caveat here is that the viewing medium - monitor, digital projector, etc. - needs to be correctly calibrated as part of the LUT building process. Happily, Light Illusion's LightSpace CMS will do exactky this, ensuring that accurate calibration is an easy process to complete, leaving the viewing conditions as the only real variable. Dailies should always be reviewed in identical viewing conditions to those the final film will be viewed in, not someone's office with dodgy window blinds leaking light.

Therefore, the workflow that should be adopted for dailies is to transfer the film via a non-creative transfer engine (a telecine/real-time film scanner calibrated to Cineon/DPX density transfer characteristics) to generate an accurate LOG image which is a clone of the OCN. This can be in any 'video' or digital format you chose, from SD to HD or greater, depending on the dailies viewing requirement and the 'telecine' used.

This 'cloned' LOG image can then be 'timed' via calibrated print LUTs to present a very accurate viewing image, true to the DoPs work.

It really is that simple, and I can't for the life of me understand why such a process isn't being demanded by DoPs and studios as the saving offered in understanding exactly what the captured image looks like is too great to be ignored. It's also a far simpler process than that presently used, where the transfer process relies on the un-calibrated creative process of a telecine and colourist.

Digital Colour Management - Dailies and DI

As an example of this totally calibrated colour workflow is via Cintel's dataMill 'telecine' (in reality a calibrated film transfer engine), which is based on their Millennium telecine, but is a transfer engine that self-calibrates to the Cineon/DPX 10bit LOG image specification, locking to the film's D-Min and outputting an accurate 'clone' digital image in SD, HD 2K or 4K without any colourist involvement.

This image data can be passed in real-time through a calibrated print LUT to generate viewing dailies totally accurate to the OCN image (or other film stocks) being transferred. Simple control of the LUTs to mimic a timer's printer lights (RGB,CMY) can provide basic timing, without distorting the original captured image, providing total guarantee that the images being viewed as digital dailies are totally truthful to the DoPs work.

The original Cineon/DPX LOG data can also be saved without LUT application for later DI grading using the calibrated 'dailies' LUTs as an accurate guide to the look of the image signed off during dailies screening, ensuring a fully controlled and calibrated digital film workflow. Even if the OCN has to be re-scanned at higher resolution for the DI process, due to the dailies process being performed at too low resolution, the use of the same Cineon/DPX 10bit LOG transfer characteristics ensures the same LUTs will generate exactly the same look with the new high-resolution digital image data as seen during the dailies review as everything is calibrated to the same known datum.

Why would anyone not work this way, especially as the methodology is totally system agnostic and provides the image control and guarantees both DoP and Studio are looking for, at a cost point that is always going to be cheaper than via the traditional telecine/colourist route?

An real-world example of the issues with dailies calibration can be read about here.