Using Chromakey and having a bad hair day! Help you Chromakey users!

todd-c63 wrote on 2/11/2015, 10:08 PM

I'm using Chromakey with a green screen. After making my video and pulling it into Magix I'm able to replace the green screen with other images, no problem there except one little thing - the hair of my subject is blond and the green screen bleeds through in places as my subject moves his head, as little as while speaking. My green screen is fairly well lit, and I'm wondering if this is the problem ... too much light on the green screen or maybe, not enough? The background I'm using is a dark blue fading 45 degrees into white. The subjects head is about center so in some of the light blue fade.

Comments

emmrecs wrote on 2/12/2015, 4:25 AM

Which version of MEP?

I know exactly what you mean about the bleed, and my answer is not going to be particularly helpful, I suspect!

As you have found, blond or similar colour hair against a green screen gives problems. I don't know how much control/adjustment you have available in whichever version of MEP you are using. I use VPX5 and the amount of adjustment it provides, espcially of "Threshold" and "Fading level" means I can come pretty close to 100%, but rarely the "whole way", as it were.

If you have the option, could you re-record the subject against a blue screen? I think that may help.

Or, could you change the dark blue/white background you're using to make the problem less visible?

In terms of lighting, I doubt that you have too much, though you could experiment with less and see what results you get.

Sorry to not be more helpful!

Jeff

todd-c63 wrote on 2/12/2015, 5:58 AM

Which vJeff. on of MEP?

I know exactly what you mean about the bleed, and my answer is not going to be particularly helpful, I suspect!

As you have found, blond or similar colour hair against a green screen gives problems. I don't know how much control/adjustment you have available in whichever version of MEP you are using. I use VPX5 and the amount of adjustment it provides, espcially of "Threshold" and "Fading level" means I can come pretty close to 100%, but rarely the "whole way", as it were.

If you have the option, could you re-record the subject against a blue screen? I think that may help.

Or, could you change the dark blue/white background you're using to make the problem less visible?

In terms of lighting, I doubt that you have too much, though you could experiment with less and see what results you get.

Sorry to not be more helpful!

Jeff

Thanks Jeff. You hit the nail on the head. It's early morning so I'm getting ready for work and don"t have time to check my version. I did resolve the issue late last night by being very conservative in adjusting the threshold slider and fader. I was surprised at how much difference just moving those a notch or two left or right made in the entire video. I also learned a trick from a chromakey tutorial online. The editor demonstrated how much easier it is to work with the chromakey adjustments (he was using a different program) by removing the replacement background and adjusting looking for the black bleedthrough. Once the adjustments are correct put the background back in and test again. This method worked perfectly. Once I did that, all bleeding issues are gone.

One feature I would like to see in a future release would be a numeric adjuster for fade and threshold with single diget increment +/- buttons to help fine tune those two adjustments. The single slider is great to get in the general range but took three or four attemps left/right to get it where it needed to be. However it is do-able and I have a much improved video.

Thanks for the quick response and dead on answer. The secret seems to be, be very patient with those two sliders until the proper settings are found.

Thanks, Todd

emmrecs wrote on 2/12/2015, 6:27 AM

Hi Todd. Thanks for the update; glad you resolved the problem and, yes, even a very small change to either of those sliders can produce quite startling changes!

Jeff

Scenestealer wrote on 2/12/2015, 5:46 PM

If you use the "Colour" button at the top of the Chroma Key effect window instead of Blue or Green, then select an area of the Blue or Green screen, you will get additional control "Antispill" that will give you much more control over the colour edges. In fact the default setting of the 3 sliders that appear, seem to be almost optimum to boot.

Also the fact that you are able to select an area of the Green probably means that it may better exclude variations in the eveness of the Green screen.

I am not sure why the extra control is not in the Blue or Green selection window though!

Peter

todd-c63 wrote on 2/13/2015, 8:47 AM

Hi

If you use the "Colour" button at the top of the Chroma Key effect window instead of Blue or Green, then select an area of the Blue or Green screen, you will get additional control "Antispill" that will give you much more control over the colour edges. In fact the default setting of the 3 sliders that appear, seem to be almost optimum to boot.

Also the fact that you are able to select an area of the Green probably means that it may better exclude variations in the eveness of the Green screen.

I am not sure why the extra control is not in the Blue or Green selection window though!

Peter

Ah, found my activation key and I have Magix Move Edit Pro 2015, so I have the button you mention. I'll have to try this and see if I can get any better quality out from my final video. I can just see the a slight green line around some parts of the subject, but I really have to look. Anyone else I've shown the test video to haven't noticed it unless I specificaly point it out.

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Thanks for the info Peter. I'm not sure if my Magix version is high enough to have this feature, but I'll check when I get back on the computer. Good to know info and a reason to upgrade :)

Thanks,

Todd