Basic CC

[Gohanto]

Hey, I'm somewhat new to after effects and I've got a rather basic question.

Whenever you see stock footage of nearly anything, the blacks never seems truely black. They seem somewhat grayish, but in the final film they're pure black. At the moment I'm looking at my stock footage and thinking the same thing.

What I've been doing is adjusting input black in Levels, but that raises the contrast. I've played with the bleach bypass method of keeping the colors under control while raising contrast and it creates an interesting effect, but not desireable for everything.

My question is basically, is there a way to lower the very dark parts of stock footage to being black without raising the contrast?

[Matt Grunau]

In short and fast, no.

You may be able to isolate some of the darks by using Effects>Keying>Extract, tweak them to taste and reapply them to via layers. That may work to a degree, and may maintain mid and high values, but the contrast will still look increased, if only in the dark portions. And it may very well be that you will stomp on some of the mids you wanted to keep in the process.

Any time you modify black levels, you are going to increase or decrease contrast. You may be able to compensate by playing with your gamma to a degree, but that's not converting X range of shades to black while retaining everything else.

Since the luminosity is one continuous shift from black to white and is comprised of 256 (8-bit color) shades of gray, altering the level of anything will affect the whole (for the sake of simplicity).


I’d go with a levels adjustment and a subtle gamma tweak. That would probably get you closest to what you are wanting.



Here's a quick example:


http://www.paramm.com/gamma.jpg

The image has been mirrored to line up the gradients. The highs and mids are pretty constant, but the black level has been raised on the left portion. The right portion is the original.

The gamma was shifted to expand aproximately the same amount as the level the blacks were raised. The two defineately show a difference in contrast though, even if only in the darks.

Of course, I am approaching this from a Photoshop standpoint in this example (since the two are so similar when it comes to Levels, Curves, and whatnot), and if anyone knows a different or better way to get the effect, please share.

[Justin_Kirch]

Great examples Rapier. I love playing with contrast levels. Usually to help you CC you would want to light your scenes according to what you are going for.

For example, for something shot for black and white, use very high contrast/low key lighting....etc.

[Matt Grunau]

Great examples Rapier. I love playing with contrast levels. Usually to help you CC you would want to light your scenes according to what you are going for.

For example, for something shot for black and white, use very high contrast/low key lighting....etc.


Yes, but he is talking about stock footage, where he had no control over the filming. My method is the only thing I could think of. I'm sure there are other ways to get what he is wanting.

Do you know of any? I'de greatly benifit from it as well, and am just as curious as he is for the answer.

Thanks for the compliment. When all else fails, I fall back to Photoshop. It's my warm snuggly place. :Drogar-BigGrin(DBG)

[Shaw]

Wow that's kind of tough. You could take the whole range and shift it down a bit. Only problem with that is you might have whites that are a bit too gray... and I'm not sure if you can do that in After Effects.

[Justin_Kirch]

As with any footage, I would just mess enough with the levels to get what I want. I usually use the exposure settings to help me achieve what I'm going for.

I like to experiment a lot with what I think works. I'm pretty sure all of you do this, but go with maybe 3 different looks, with all different looks. Do the best you can to make them contrasting to each other.

I think what Rapier said is the best way, but you can always use your own way to try and get what you want.