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“100% or EBU Bars” for HD 25fps video
Hi everybody,
I’m delivering 1280×720 video to a transfer house that will move it onto Digibeta. I’m being told by the client to use “100% color bars, but EBU will also be accepted.” It’s going to be broadcast in Europe.I’m using FCP’s “More Bars and Signals” generator. Can anyone tell me what the following values mean, and maybe which I should be using?
Digital ColorBar (100/0/100/0) vs (100/0/75/0)?
Thanks!
-JustinVideo editor, animator, composer, producer
JustinCrowell.com -
8 Replies
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Hi Justin
Pretty much all UK and many European broadcasters request 100% colour bars, By this they are generally referring to 100% luma and 100% chroma.
So the 100/0/100/0 would be the ones to use for 100% bars.The 100/0/75/0 refers to 100% luminance but 75% chroma. These are generally known as EBU bars so it seems you cant go wrong if they accept both
Hope that makes sense.
best wishes
Neil
http://www.patience.tv8 Core MacPro, Kona 3, Tangent Wave, Mackie Universal
i7 2.7 Gig MBP (non retina) 16Gigs Ram Blackmagic Monitor Mini -
Thanks so much, Neil! That’s actually what I suspected the 100/0/100/0 was indicating–it’s just so startling to see those near-illegal colors!
I appreciate the help!
Video editor, animator, composer, producer
JustinCrowell.com -
No problem and yes if you are used to using 75% bars which is normal US spec then 100% bars do tend to look super bright. As I am in the UK I am the other way around and whenever I see 75% bars they always look a shade dull. Hey ho 🙂
best wishes
Neil
http://www.patience.tv8 Core MacPro, Kona 3, Tangent Wave, Mackie Universal
i7 2.7 Gig MBP (non retina) 16Gigs Ram Blackmagic Monitor Mini -
Neil is right.
When talking about 100% or 75%, we refers to the White bar only (100% vs 75% Luma).
The Color Bars CAN NEVER BEEN 100% because the Green, Cyan and Yellow bars would be fully illegal.
As Neil say, the EBU are 100% Luma (for the white ), and 75% saturation or the colored bars.
rafael -
It’s interesting…in FCP white doesn’t change between 100/0/100/0 and 100/0/75/0, but the colors all seem to drop to 75% luminance without a chroma change. So wouldn’t that mean it’s Chroma/0/Luma/0? Or am I confused?
Video editor, animator, composer, producer
JustinCrowell.com -
That is because with the 2 examples you give 100/0/100/0 represents 100% luminance and 100% chrominance and 100/0/75/0 represents 100% luminance and 75% chrominance so in each case the white would be the same.
best wishes
Neil
http://www.patience.tv8 Core MacPro, Kona 3, Tangent Wave, Mackie Universal Symphony 6.5 FCP7
i7 2.7 Gig MBP (non retina) 16Gigs Ram Blackmagic Monitor Mini Symphony 6.5 FCP7 -
Right.
On both cases the white bar is 100% (R=G=B= 1).
Pure Luma. No Chroma.
If you have a look to the Vectorscope, any white/gray will show up as a single dot in the center.
It will have a luma value (Y), but U=V= 0. So Chroma = 0.
rafael -
Ok, still trying to puzzle through this. It being only a chroma shift makes sense, because if it were a luma shift, the black and white would change. But when I open the waveform scope and make the switch, there is definitely movement for the areas between the black and white bars. Does this have something to do with the interrelatedness of the Y and the RGB values in FCP?
Thanks for all the help…REALLY appreciate it!
Video editor, animator, composer, producer
JustinCrowell.com
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