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How do I get black in an image file to be treated as black?

Posted: Tue Oct 19, 2010 22:09
by nickharambee
Hi

I have a png file which is mostly black but with areas that are transparent:

Image

I would like to use this image on one layer and then have other layers beneath show through the transparency, but not the black, which would stay opaque (i.e. opacity 100%). Something like this:

Image

At the moment when I try this Resolume is treating the black area in the image as transparent, so effectively nothing on the png layer is showing. I have tried various blending modes, but still not got it working as I'd like.

Could someone point me in the right direction?

Thanks

Nick

Re: How do I get black in an image file to be treated as black?

Posted: Tue Oct 19, 2010 22:30
by VJair
convert it to a jpeg and luma key the white areas.

Re: How do I get black in an image file to be treated as black?

Posted: Tue Oct 19, 2010 23:13
by nickharambee
Thanks a lot VJair. That sorted it.

Nick

Re: How do I get black in an image file to be treated as black?

Posted: Wed Oct 20, 2010 14:05
by edwin
If the .png has a proper alpha channel this should just work out of the box. Can you send us the .png?

Re: How do I get black in an image file to be treated as black?

Posted: Wed Oct 20, 2010 22:23
by nickharambee
sure, to which address should i send it?

Re: How do I get black in an image file to be treated as black?

Posted: Thu Oct 21, 2010 19:58
by Joris
You can mail any suspicious packages to support<at>resolume<dot>com ;-)

Re: How do I get black in an image file to be treated as black?

Posted: Thu Oct 21, 2010 20:20
by nickharambee
mmmh. just tried again and this time it works, with luma key 1 blend mode it behaves just like the jpg (with white instead of transparency) and with hard light blend mode it works as well, with the crossfader half way towards the top (black) layer. when the crossfader is in the middle the bottom layer starts to show through the black. presumably this is the expected behaviour.

Anyway, I've learnt something about luma keys with white and black acting as transparent in the process, so thanks very much

Nick