# Mask on chromakey

**URL:** <https://rossvideo.community/t/mask-on-chromakey/12396>\
**Category:** Production Switchers\
**Created:** [September 26, 2012, 6:55pm UTC](https://rossvideo.community/t/mask-on-chromakey/12396 "2012-09-26T18:55:00Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![chableblank](https://rossvideo.community/letter_avatar_proxy/v4/letter/c/e495f1/32.png) [@chableblank](https://rossvideo.community/u/chableblank)\
**Post date:** [September 26, 2012, 6:55pm UTC](https://rossvideo.community/t/mask-on-chromakey/12396/1 "2012-09-26T18:55:00Z")

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Hi,

I’m using Carbonite 2M running 6.1 software version.

I shoot somebody on green screen in order to perform a chromakey. In my green studio I have a LCD monitor, of course the picture in that monitor could content green color that’s the reason why I wish to apply a mask forcing the foreground without chromakey applied .

To perform this I put the mask in “BOX” for instance and the M-frce parameter in ON position.

In this configuration instead to get box with foreground forced inside I get black box masking the background.

Is there a solution to achieve what I wish ?

Thanks

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**Author:** ![garycook](https://rossvideo.community/letter_avatar_proxy/v4/letter/g/b9bd4f/32.png) [@garycook](https://rossvideo.community/u/garycook)\
**Post date:** [September 27, 2012, 12:57am UTC](https://rossvideo.community/t/mask-on-chromakey/12396/2 "2012-09-27T00:57:00Z")

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The reason why you get a black box is because the chromakey not only creates an alpha signal from the green content, but it also removes green content from the video signal (replacing it with black). So when the mask is forced you get black.

One solution is to use another key on top.

Use the same source as the chroma key.

Use a self key with %100 gain (or %0 clip).

Use a box mask with M-Frce=Off and M-Inv=On

Gary

[#Vision](https://livinglive.community/search?s=tags%3A%22Vision%22&executesearch=true)

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**Author:** ![chableblank](https://rossvideo.community/letter_avatar_proxy/v4/letter/c/e495f1/32.png) [@chableblank](https://rossvideo.community/u/chableblank)\
**Post date:** [September 27, 2012, 11:37am UTC](https://rossvideo.community/t/mask-on-chromakey/12396/3 "2012-09-27T11:37:00Z")

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In fact I believed that chromakey was not active at all inside the box mask including the green removal.

I almost did the same thing, on the second keyer I set DVE full screen and I cropped it. your solution seems to be better because with masks I can use patterns.

Thanks

[#Vision](https://livinglive.community/search?s=tags%3A%22Vision%22&executesearch=true)