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Blacks below 7.5 Help!
I am about to output several versions of a show that has been digitized using, and is to be output using Component Betacam 525 setting on the io, through the component signal path.
This is my first FCP online.
The system is allowing black levels below 7.5.
How can I prevent this. In several cases I have color corrected muddy greys to black, and the aja is allowing these low values below 7.5 on analog output. If I raise the level of the blacks, too much of the shot gets greyish – I want the look I have, but I want the blacks clipped at 7.5.
I know there are filters for excessive chroma and luma values. What about this illegal blacks issue? I have been working on a Media 100 for several years, which does not allow output values below 7.5 and above 100 on analog in and out.
Thanks in advance for any help
Signed
Deeply Afraid of Rejection -
5 Replies
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If you have the Io control panel installed check the output section. There is a button to add 7.5 setup to analog outputs.
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Hi,
Thanks for the suggestion. What I require is that the blacks be clipped at 7.5. If I add setup to the whole show the blacks will grey.The people at AJA swiftly responded to this in their tech department:
> In regards to black levels: The Io does not clip
> super black video levels;
> however it does rescale the luminance on capture and
> playback.
>
> In the case of betacam, 7.5 IRE is scaled to 0 IRE
> on capture; scaled back
> to 7.5 IRE on playback. In other words: Black in FCP
> is 0 IRE; Black with
> betacam is 7.5 IRE – again the Io handles the
> scaling but does not clip the
> super black.
>I do understand the technical explanation given by Rudy, however I believe there must be a method, or one should be developed to ensure no illegal black levels. If there is no such thing as below zero in FCP, and the AJAio scales all zero blacks to 7.5, then how can a “superblack” exist, and how can I end up with analog video values below 7.5. Based on this information it should not be possible.
They suggested trying the broadcast safe filter which, unfortunately does not have any effect on the blacks (FCP4.5).
Is there another suggestion for not allowing black levels below 7.5?
I can go in and tweak each shot, but the point is that they have noisy greys, that we want to have disappear into black. Making the shot legal by raising the blacks, ruins the aesthetic. Clipping the blacks at 7.5 is the desirable option here.
Thanks, hopefully there might be another suggestion.
Tim
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…besides digitizing the whole show from the AJA io into my Media 100 to make it “black safe”… LOL sort of…
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Maybe I’m missing something? If you keep your blacks at or above zero in FCP, they should be at 7.5 or above on output, if you’re using analog outputs on the Io. Of course, if your scope says something different, then you need to adjust accordingly any problem areas in FCP before outputting. Most likely you have some blacks below zero in your FCP project.
Tony!
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I experienced the exact same problem with my IO/LA. It only reared its head with 10bitUC timelines. The exact same footage pasted into an 8bitUC timeline did not go below zero. AJA, although responsive, did not have an answer. I ended up dropping in a ‘Joe’s Filter’. His LEVELS filter, if dropped onto the clip/ or nested sequence eliminates all of the below zero instances. I didn’t even have to tweak it at all. Perhaps another alternative to adjusting the black level with fcp color corrector is to try changing your gamma with the gamma correction filter– try a value of 1.1 or 1.2. This will give you a ‘darker’ or deeper look, without lowering the absolute black level below zero.
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