multi light source compensation

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mzbe
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multi light source compensation

Post by mzbe »

I'm looking for a way to compensate for multiple light sources (different color temparatures).
E.g. here is an example of how SilkyPix approaches this http://www.fredmiranda.com/forum/topic/1422159 issue.

Would love to be able to replicate this with ColorWasher, hoping to gain more granular control and better results, as well as not having to use Silkypix every time.

HaraldHeim
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Re: multi light source compensation

Post by HaraldHeim »

The only way to do this in ColorWasher is to apply it two times. But you additionally have to create a selection or layer mask before you apply ColorWasher to individually process the yellow and the blue colored image areas. Here are some more detailed instructions.

1. Go to Select > Color Range and click on a blue image area to create a selection of it.
2. Apply ColorWasher and remove the blue color cast.
3. Go to Select > Color Range and click on a yellow image area to create a selection of it.
4. Apply ColorWasher and remove the yellow color cast.

Alternatively you can duplicate the image on two layers, add each selection as a layer mask and apply ColorWasher to both layers. Then you can afterwards use the opacity of each layer to balance the colors.

When trying that with the SilkyPix example, it looked even a bit better when processed this way with ColorWasher than with SilkyPix. The key factor is to create good selections for both color areas.

This looks like a good feature for a future update of ColorWasher.

mzbe
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Re: multi light source compensation

Post by mzbe »

Thanks for the reply. I was aware of the multiple selection possibility.
I'm wondering though if SilkyPix doesn't use image geometry in addition to color ranges - if you have multiple light sources, it stands to reason that they would affect different areas of the image?
This is where manual selections ultimately become time-consuming (not to speak of areas with mixed lighting, where the beams overlap ...).

I'm glad to hear that you are considering this problem as an area of future improvements and innovation. This could be really big for all those of us who don't always gel their flashes as they should, or have to shoot outside of a controlled environment.

HaraldHeim
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Re: multi light source compensation

Post by HaraldHeim »

In the example image the blue and yellow areas are interwoven, so a "geometrical" or local approach would be ineffective - unless you build a 3D model of the image, which would be even more time unpractical.

To avoid such a photo you can place a yellow foil in front of your flash when shooting at sunset.

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