[Tig] Display Management for DI

Laurence Claydon laurence
Fri Mar 11 09:43:08 GMT 2005


Having consumed two whole mugs of coffee this morning, I retired to my desk and deceided to initiate a thread....

Having recently supplied and installed a number of DLP-Cinema projectors for DI use in the UK, it would appear that there are a number of views and practices on how display management for 'film-look' should be implemented for projection devices and environments. In other words, there are no standards!

I do, however have a few suggestions. Any audio engineer will recognise them as dynamic range optimisation!

1. Black-level/Contrast optimisation 1: DLP devices commonly used have a finite black-level. Current practice for 3D preview LUTs seem to include scalar compensation for the clear film-print base, equivalent to ~2 footlamberts of screen illumination. Surely the best place to achieve this is at the light-source of the projector, set to 14ftL, rather than scaling the input signal in the LUT and having 16ftL (2 of which you will never use!) on-screen.

2. DLP-Cinema devices have very accurate RGB primary and white-point calibration which are also very repeatable. So far when preparing such equipment for display profiling, I have set the projector to produce P3 RGB primaries with x=.335, y=.350 (CCT=5400K) white point on each occasion and then 3D preview LUTs have been generated based upon this profile. This at least maintains consistency when viewing in different locations on similar equipment

3. It is worth noting at this point that Texas Instruments have built-in the facility to upload a 3D preview LUT directly into the projector (I know some folks have already been doing this for quite a while....), surely the best place for it as it does not compromise the dynamic range of the DVI/HD-SDI link into the display device--- (LUT-box-widget-colour-corrector manufacturers take note!)

I have further thoughts which cannot all be covered in one posting, but hopefully we can start off as little acorns and then grow into oak-trees.....

Laurence Claydon
Bell Theatre Services Ltd
London UK

I do not work for Texas Instruments, or any of their OEMs 





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