superimposing / mixing 2 video tracks with full alpha

Mindmatter wrote on 10/2/2019, 9:00 AM

Hi alll

this might seem like something obvious but...is it possible to actually mix 2 channels or more with 100% alpha as opposed to a 50/50 kinda thing? I'm probably missing something totally obvious right now but I'm scratching my head over this one..

The job is to shoot bubbles in front of a black background, many bubbles falling down in slomo,. and the producer wants each bubble to be in focus, which is almost impossible even at f16. So I thought to shoot several takes with 1 layer of bubbles each, as flat as possible and just mix them all together in post.

thanks!

Comments

Marco. wrote on 10/2/2019, 9:10 AM

Compositing mode "Add" might be your choice. Though any compositing only can sum up luma values to a max of 1 (where 0 is black and 1 is white) in the end.

Also you would need to ensure each of the bubble shot is color corrected in the way its black levels equals R'G'B value 0 before doing the comp, else the black background would come up as gray in the end.

Mindmatter wrote on 10/2/2019, 9:15 AM

many thanks like always Marco, I'll give that a try as soon as it's shot.