Hi Coyowin – try to post a direct link for what you’re talking about when you post questions like these. I’m not sure exactly what you’re talking about – but a lot of times for those stain type looks we’re shooting various dark opaque liquids dropped into clear water/alcohol etc. and filming it against white. Then we turn that footage into a luma-matte layer etc. over paper textures/colors etc.

Not sure if that’s what you’re thinking about – but hope it helps,

// jayse

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