Used a white backdrop for photos.. now, how to PP to get bg to be 'true' white?

cal_gecko

I recently took a bunch of photos for some friends of their kids.. obviously my white balance was a bit off - probably because I was using several different types of light sources.

So, now that I'm in the post-processing stages.. is there a relatively easy way to set the white balance on each shot so that the background is "white"?

I'm using a Mac, and Aperture 2 for my PP work. Here's a couple examples of what I'm talking about...











Thanks!

pathfinder

Aperture users??

Cute kids!

If you had used higher power lights on your background, it would be burned to white in your original image, eliminating the need for post shooting editing of the white background.....

rsquared

I don't know Aperture, but Lightroom has an eyedropper tool for the WB, and I would assume Aperture should do something similar. You select the tool, and then click on something "neutral" (white, black, or a gray card usually) in the image, and it automatically sets the WB. In this case you would click on the white background it it should correct the WB.

pathfinder

What if the light hitting the background wasn't neutral and truly white? The white balance eye dropper is a global edit - it will change the color balance of the whole image, including the kids, not JUST the background.

In Photoshop, create a new, second layer. Select the white area with the color select tool, or select the extreme highlights, mask out the kids with a soft mask, and then use a curve to drive the backgrounds to white.

I don't know if Aperture will accommodate local, rather than global, editing since I haven't used it since the advent of Lightroom2.

SLRdude

pathfinder wrote:

In Photoshop, create a new, second layer. Select the white area with the color select tool, or select the extreme highlights, mask out the kids with a soft mask, and then use a curve to drive the backgrounds to white.

that's what I'd do, except that I was lazy and I just cranked up the levels.
It took me less than 3 minutes including the mask and it looked pretty good.

pathfinder

I can do all that I stated in less than three minutes also, but not a fast as you just steepening a curve, that's for sure.

cal_gecko

pathfinder wrote:

In Photoshop, create a new, second layer. Select the white area with the color select tool, or select the extreme highlights, mask out the kids with a soft mask, and then use a curve to drive the backgrounds to white.

Wow.. .that sounds very complicated ... last time I tried to use photoshop and layers,.. it took me almost 10 minutes just to try to find out HOW to add a new layer.

Why add a layer in the first place? Why not just select the white background and modify that?

pathfinder

Because I was attempting to not have any effect on the color balance or luminosity of the children's images. I wanted to mask them out, so that the changes to the background had zero effect on them.