[Bf-vfx] Mango Samples with ACES via rrt_sRGB

[Brecht Van Lommel]

Hi,

On Thu, May 17, 2012 at 6:36 AM, Troy Sobotka <troy.sobotka at gmail.com> wrote:
> The sRGB RRT is quite well defined. If indeed the tests show a correct
> transform, the creative intent via a LUT would be useful to put into a chain
> before the final sRGB display transform.
>
> The entire gamut likely won't be mapped to display, but rather a more
> classic curve at the head and toe with a clamp at over / under HDR values if
> memory serves.

>From what I read, the RRT is still in beta, and it has a particular
"look" to it, it's intended to be be film-like, not neutral. The
official documentation for it is not public yet, but see e.g. here:
http://www.reduser.net/forum/showthread.php?77353-ACES&p=997321&viewfull=1#post997321

>> * For the spi-vfx and aces configurations in OpenColorIO, the scene
>> linear to display sRGB transform is not invertible, it can only be
>> applied in one direction. Seems quite silly that you can't pick a
>> color and get it back exactly the same in a render.
>
> The SPI sRGB LUT is a 3D LUT if I am not mistaken, so chromacities and non
> linear is taken into account in the SPI workflow. dt16 and mp16
> (spi-anim);are the input transforms used for textures and traditional matte
> paintings IIRC.

I know this, it just seems a bit silly to me that you then can't get
an 8bit matte painting, map it to the background and get it rendered
with the exact same colors.

>> * The aces configuration does not define good color spaces for
>> texture_paint/matte_paint/color_picking. The spi-vfx configuration
>
> I would think sRGB would suffice for a few of those. ociobakelut can be used
> to generate needs beyond that, such as from ICCs.

How do you convert from sRGB to ACES though?

Brecht.