[Tig] LUT file format

C├ędric Lejeune c
Thu May 11 01:33:31 BST 2006


--
Thanks to oktobor for supporting the TIG
--
Hi Rajesh,

this file is a 2D LUT file with some tweaks, supported by Lustre (not by
Flame or Smoke). There is no tool to generate LUTs in Lustre, you would
create this using a text editor.
Keywords:
3DLUTMatrix
This is a 3x3 RGB matrix that allow to control saturation
first row says that for a value of red 85% goes to red channel, 7.5 goes
to green and 7.5% goes to blue. It was a hack before we got support for 3D
LUT long ago.

LUTDensity means the value are negative densities
1.0 means there is no gamma compensation

first value value corresponds to a patch of grey (10bit) you would send to
your lab, then you'd just put the values from the densitometer.

To achieve a translation from film colourspace to 709 I would strongly
recommand using a 3DLUT as OutputLUT in the Render/Output menu, you could
then use adaptative colour shifting you cannot do in 2D LUTs. Lustre
supports those from Kodak KDM, Rising Sun, ARRI and its own open format.

Hope this helps,

C?dric
c at workflowers.net
www.workflowers.net
+33 6 29 43 62 18



On Mer 10 mai 2006 17:52, Rajesh Ramachandran a ?crit :
> --
> Thanks to oktobor for supporting the TIG
> --
> I am looking for pointers to make sense out of a .LUT text file
> (contents pasted below) that I need to apply to a DPX sequence to turn
> it from print density to the 709 color space (?). The DI facility tells
> me that the file was generated out of Lustre but I have no familiarity
> with that system to be able to verify that. I have scoured the web for
> any documentation of this file format or the keywords in it and have
> found just one reference which really does not explain how to use the
> numbers in the file. I really need to understand this file so that I can
> incorporate support for it in our Digital Cinema mastering application.
>
> Thanks.
>
> --- .LUT File Contents ----
>
> 3DLUTMatrix
> 0.85  0.075 0.075
> 0.075 0.85  0.075
> 0.075 0.075 0.85
>
> LUTDensity 1.0
>
>
> 0	4.08	3.81	3.81
> 51	3.96	3.71	3.71
> 102	3.78	3.51	3.53
> 153	3.58	3.29	3.31
> 204	3.23	2.97	2.98
> 255	2.83	2.61	2.58
> 306	2.36	2.18	2.12
> 357	1.88	1.76	1.68
> 408	1.39	1.32	1.26
> 459	0.98	0.97	0.92
> 510	0.67	0.70	0.69
> 561	0.49	0.52	0.54
> 612	0.34	0.36	0.40
> 663	0.23	0.24	0.30
> 714	0.17	0.16	0.23
> 765	0.12	0.12	0.19
> 816	0.09	0.09	0.16
> 867	0.07	0.07	0.14
> 918	0.06	0.06	0.13
> 969	0.05	0.05	0.12
> 1023	0.04	0.05	0.12
>
>
>
>
>
> _______________________________________________
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> TIG wiki: http://tig.colorist.org/wiki
>




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