Adding Shadows

[Finn]

Hey all,

I'm planning a series of shoots that, because of the logistics of running a shoot in the actual locations it's going to be easier to shoot the backgrounds and then shoot people on greenscreen. I'm well aware of the potential pitfalls of this method (such as matching perspectives, matching lighting, matching colour balance and the ensuing cutout) but figure I have enough experience to manage well. What I don't have much experience in is adding shadow to make the person really sit well in their new environment.

My background is photography so I understand what the shadows should be doing and would be doing given the lighting treatment used.

What I'm unsure about is the best workflow for achieving great, believable shadows. My instinct is one or more masks per shadow with either curves or exposure or perhaps a darker background (taken from the RAW) blended in. Am I right or way off? What do others' do?

Many thanks in advance for any help!

Finn

[Finn]

Bumpety-Bump.. Anyone?!

[flexmanta]

The new exposure adjustment layer in CS4 does a very good job simulating lowering exposure (not so much for increasing it), as it provides the right combination of luminosity and saturation effects. It even lets you work in stops. You can even measure the shadows that would be cast in your location during shooting, and then create those shadows with a brush on the comp.

[Finn]

Hey Flexmanta,

Thanks for replying! Just a couple more points -

Do you think using the exposure adjust is a better option than using a second, darker version of the original RAW file?

Anyone have much experience using Displacement maps to match the contours of the object that the shadow is falling against?

Thanks again for any ideas!

Finn