Blackmagic Forum

Hi,

I use a custom made LUT for legal colors that I put in the "1D LUT output".
Now, if I deliver with the legal colors set (or even auto), it will move the black up again..

I would have imagined that.. because the colors are fine, nothing would have happened, so I do not understand the mechanism behind this : is it blindly scaling the colors ? even in auto ?

If I set it to "no scaling" then everything is fine. Question, if auto scales, does it mean that it does not work properly, or that my LUT is not working as it should ?

Cheers,
Pe

The way i like to work is that the "scaling" is never done with a LUT. A lut is always to be used as [0-1023] ([min-max]) and the scaling will do the rest...

(just as suggestion)

waltervolpatto wrote:The way i like to work is that the "scaling" is never done with a LUT. A lut is always to be used as [0-1023] ([min-max]) and the scaling will do the rest...

(just as suggestion)

But then, how do you previsualize the final image in Resolve ? (ok, I have a Declink on its way, so I can look on a TV)

I've had this question before too, Resolve has no way of compressing the colors into legal range on export.

It does, however, scale the video color to legal range when outputting through external video. It should be possible to use a device like a KiPro or a Hyperdeck to write the video over SDI.

This is realtime and slightly slower than running it through FCP7 Broadcast Safe. So far I've been unsuccessful doing it with my KiPro.

you don't. The image only have a meaning if you visualize in the proper viewing environment: if you grade for TV then a TV calibrated set should be used.
That said, you can calibrate close enough to a spec and use it, but I do not advise it.

If you grade for internet, then yes, you can use the GUI and calibrate the monitor for the correct sRGB spec. in that case what you see is want you get.

The GUI is just what it is: a General User Interface, not a Grade environment.

If you look at the math, you can have a full range displayed in a full range Monitor (RGB/444 on the GUI) and when you apply the LUT for the final output the RGB444->YUV422 scaler will generate an image that is really really close. That is true if your viewing environment (GUI?) is setup for bt1886 TV environment, and most of the monitor out there are not even close.

waltervolpatto wrote:If you look at the math, you can have a full range displayed in a full range Monitor (RGB/444 on the GUI) and when you apply the LUT for the final output the RGB444->YUV422 scaler will generate an image that is really really close. That is true if your viewing environment (GUI?) is setup for bt1886 TV environment, and most of the monitor out there are not even close.

Exactly ! But now the LUT helps me seeing the scope in the 'right' range, and an approaching image.

I have now a real TV monitor (my target) and it is close to what my GUI is doing (not exactly the same thing, it seems darker but it is close !)

Thanks for your explanations