I've been working on a project where I need to fill in a bottle of water with thick, black crude oil (it's supposed to be a visual metaphor).
I initially found this question, but following its instructions only got to this:
This website makes the bottle look darker than it actually is. When I play with the levels, it either looks too posterized, compromising the image's integrity, or like gray transparent water. Basically, I can't seem to get the black thickness similar to the bottle in the other question. I think it may be because of how the water bottle is lighted, so maybe I need a different starting image.
But I'd like to know if this is possible to do? Or would it be a better idea to just make fake oil from scratch and take a photo over white drape?
Here's a link to the original bottle, the website causes errors on the image https://i.stack.imgur.com/2xwrE.jpg