Fixing mixed color temps

Discussion in 'Digital Darkroom' started by sarah_lange|1, Oct 17, 2014.

  1. This is a toughie. I shot a series of headshots in the conference room of an office. There were big spotlight-style lights overhead, probably florescent? I asked if some could be turned off. Found that I had to have all on or none on. No in between. I would have preferred none on but then the lens could not auto focus as it was dark. So I kept them all on.
    I shot in RAW. But the problem is that the skin tones on some are yellowy-greenish. They looked jaundice. In order to fix that, the rest of the image becomes way way too blue/red. I used gray background paper and have been using that as a rough color guide (it's not the 18 percent gray Savage paper but a medium gray).
    I am wondering if I can adjust various sections of a photo differently re color? In ACR. I don't think so but wanted to see if anyone has any suggestions.
    Thank you!
  2. Assuming you are a freelancer hired for the assignment, why didn't you bring and use your own lighting?

    But to the existing problem. The gray is a good place to start but also see if any of the folk were wearing a white shirt, and
    WB with that as a base. You'll likely have to fine tune from their but it will give you a starting point.
  3. I would use the RAW converter to save two different JPEG or TIFF versions of the image, one with the skin tones looking correct, another with the background looking correct. Then put them on different layers in Photoshop, and use a layer mask to make the correct skin tones show through.
  4. Ray House

    Ray House Ray House

    Black & White might be an alternative solution as a last resort.
  5. Thank you for responding.

    I did bring lighting, sorry I wasn't clear on that. In the early shots I used one sb910 with translucent umbrella and one stand-up reflector.
    That seemed to work well but after a few people I decided to ditch the reflector and use a second flash and umbrella on the fill side for
    more light. That seemed to work well to. It could be that it's the reflector shots that most show this green skin, maybe the office lighting
    was more visible or problematic in those, not sure.

    The two photos sandwiched together sounds like a good idea. Thanks.
  6. This sounds like an excellent challenge for the WPPC! Still looking for volunteers after next week.
  7. As a variation of blending 2 images processed differently, recent versions of PS let you use a color temp adjustment brush in ACR so you can paint in the desired temp across the single image. LR has the same feature.
  8. Next time, you need to gel your flash to produce the same ghastly greenish light as the fluorescent fixtures and then set a custom WB for whatever color that ends up being. Then set a shutter speed of 1/60 (1/50 in the UK) to capture a complete power cycle (during which the color of the fluorescent light will fluctuate). Another possibility is to light your background as well, using more flashes and radio slaves. However, you have to outpower the fluorescents by maybe a couple of stops (with your shortest possible flash sync speed) to make this work.
  9. Howard wrote "recent versions of PS let you use a color temp adjustment brush in ACR"
    Thanks I didn't know that.
  10. Why not manual focus (or auto-focus and then switch to manual) with the lights on and then turn the lights off? The focus will stay fixed.
  11. Thanks very much everyone for these great ideas. Howard, I wonder if CS6 counts as a recent version and has the color temp adjustment brush. I will try to find out.
    Thank you Sarah Fox. I probably should have gelled the flash. But, not sure they were florescent, I do think so now. Also, that would've affected the entire scene, including the portions of the photo lit more by the strobes…… right? Would I not still be left with the mixed lighting problem I'm having now? Or would adjusting properly for the office lights with the gel not affected the strobe lighting?
  12. Sarah L., to give you an idea of what's possible in color correcting images shot under less than flattering light check this old PN thread where I offered my take on correcting for green cast (note the skin tones)...
    That's as bad as it can get and we all worked off of a jpeg.
    The color temp adjustment brush is a good idea, but looks like a lot of work if you have to correct a number of images with these color errors, and if so, you might try ACR's HSL adjust to correct just for the jaundice skin. Then save that to xmp and apply to the rest.
  13. Sarah, if the overhead lighting was fluorescent, and if your flash had the same "fluorescent" green/yellow cast, then there would have been no significant imbalance in the WB. Any imbalances would have been fairly subtle. The real evil brew would be some combination of tungsten and fluorescent. In that situation you would have to kill either one or the other and gel your flash to whatever type of lighting you keep.
    Rather than to gel your flash, you could also use one of these:
    The gold one emulates tungsten, and the ghastly green one emulates fluorescent.
  14. Thanks Tim. That link looks helpful. I do have a lot to correct but I just want to correct the proofs enough so that the subjects don't really notice any color issues. Then when they choose which photos they'd like (one or two each) then I will need to really edit those correctly.
    Thank you Sarah. This is very helpful too. Appreciate it. I have trouble grasping gelling. Hard to get beyond the (wrong) idea that adding to the ambient color temp (i.e. florescent or tungsten….) doubles up and worsens the color cast rather than balancing it out.
    Another side questions is this. How to tell what type of office lighting you're facing. Is there a way to tell? There is of course never a sign on the lights that say 'florescent' or 'tungsten' etc...
  15. It is interesting that of the eight or so people I shot during this session at their office only one has this overly warm green jaundiced look. (I know she did not look this way in real life.) I don't know how to explain this. Could be the reflector on one side with one flash and umbrella on other did not overpower the fluorescents enough but I used reflector with two or three people before switching to second flash with umbrella set-up. The color on everyone else isn't great and needs tweaking but none is as bad as this one woman.
  16. It is interesting that of the eight or so people I shot during this session at their office only one has this overly warm green jaundiced look. (I know she did not look this way in real life.) I don't know how to explain this.​
    It could be the shutter speed was a mismatch with the flicker of the fluorescent lights. That happens randomly, and I have been caught with it lately.
    One of my methods to correct mixed color temperatures is to desaturate only one color, green or yellow, depending on the specific case. Using the history brush after desaturating a color, removing yellow on a face for instance, works well too.
  17. How to tell what sort of lighting: You can ask. You can stand on a chair and open the fixture to see. You can photograph a white piece of paper with a WB preset (tungsten or fluorescent). Then look at the RGB histogram. If the R, G, and B peaks are pretty well aligned, you've probably guessed the right type of lighting. Then gel your flash accordingly.
    I wonder if the one jaundiced woman is a metamerism issue. Foundation may appear a natural skin tone under daylight, but it may appear different under fluorescents or any lighting of differing spectral composition. If you're like me, you might not notice strange color casts with all the goings on of a shoot, but then when you're doing your postprocessing at the quiet of your desk, these casts become evident. Recently I shot some pine trees in the setting sun, and they looked rather yellowish/orangish and somewhat devoid of detail. I thought, "Did they really look like that?" It turns out they did. On a side note, I don't know how old you are, but do you remember girls with orange faces back in the early 70's. Foundation was often orange back then!
    Your jaundiced woman might also have been farther in the background, or her face might have been lit more heavily with fluorescent lighting, rather than your flash.
  18. When I use my own lighting, I will usually try to kill the ambient light by shooting at the max flash sync speed, which is 1/250 of a seconds, and a high f/stop. You can shoot a test shot without your flash(es) to make sure that the frame is black. At that point you are in control of the light, whatever is overhead.
    Of course if your flash was to fill only, and you were using ambient light from a window, or the room itself, for example, then the only way out is to gel your flash like Sarah Fox said.
  19. Oops, the max flash sync speed I am talking about are those of my Nikons. I was not making a blanket statement.
  20. Thanks again everyone. That is really interesting Bruno. I was aware that you could overpower the ambient but you put it in such a way that I really understood, killing the ambient with max sync speed and high aperture and testing by seeing if the frame is black. So, to be sure, if the frame is black, the overhead office lights are a non-issue? I also use Nikons.
    Thanks David. I have been able to Band-Aid these photos with isolated color desaturations but it's all eyeballing it and far far from ideal or 'correct'.
    Thanks Sarah. I do remember the foundation of the '70s! This woman may've been wearing a foundation with a tone that is causing this. But she'd have to be using it on her chest too (open blouse) so I don't know. That's a good guess. Thanks for the tips on the type of lights.
    One things I keep forgetting to do it have subjects at beginning of shoot hold a gray card, I have a fancy one with different grays, wide stripes. Not sure why there is more than one gray but I should use that instead of trying to remember what color the walls really were.
  21. Sarah, if the test frame without flash is black, then ambient light cannot affect your final image. For color balancing, I have my subject hold this:
    With Lightroom, it is a great combination.
  22. Killing the ambient with a fast shutter speed is certainly one way to handle the situation. However, FAIW, unless you have enough flashes to light the entire room, you might have a dark or black background. That might or might not be OK, depending on what you're trying to achieve. Many photographers will "drag the shutter" to incorporate enough ambient light for a more natural looking background, but of course you can only do that with your flash WB balanced to the ambient WB.

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