Color Temperature Issue

<p>I was assigned to take indoor academic seminar picture for newsletter in one university lecture theatre without using flash. The spot lights on podium were daylight color temperature fluorscent light tube (Kino) while the lecture theatre ceiling light were warm fluorescent light tubes. After taking wide angle picture to cover speakers and students, there was too color temperature appeared on the picture. The lighting on speaker was white but the rest of the room was warm white. How to make camera adjustment before shooting ? I was using Nikon D300 (auto white balance) and Sigma 10-20 mm. </p>

<p>shoot raw and adjust later. frankly I would not worry about it. </p>

<p>Ellis is right abut shooting raw but there is more to it. If the color temperature is very far from each other you might need to have two white balance settings in the same image.<br /> <br /> Lightroom is not sophisticated enough but there are other raw converters that can apply white balance locally to different parts of the image. The solution with the most control though is to develop two raw images from the same shot, one white balanced to the spot lights on the podium and one to the rest of the room. Then you blend those seamlessly together in photoshop or another image editor that can handle layers and masks.</p>

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<p>Can you up load the photo to show us what concerns you?</p>

<p>Pete S - Which raw converters can apply white balance locally?</p>

<p>Tom M</p>

<p>Tom - I haven't checked everyone but Bibble 5 can do it. http://www.youtube.com/watch?v=FIEGDOjblX0</p>

 

<p>Pete - very nice. Thanks. I wasn't aware of that. For mixed lighting situations, I usually either do it by making a couple of different raw conversions and paint in whichever one I want, or do it using one of the NIK U-point tools like Vivacity, in PS, after raw conversion. In principle, it should be better to do it at the raw stage.</p>

<p>Thanks again,</p>

<p>Tom M</p>

<p>The best thing to do in cases like this ... which are more frequent than not when shooting indoors at public places ... is to shoot RAW and perform a one-time manual WB setting which any of these cameras can do in seconds. This doesn't solve the issue, it mitigates it enough to more easily correct it in post.</p>

<p>Lightroom has a local brush to deal with this quite effectively if you know how to use it.</p>

<p>Here is a shot that shows an overly warm ambient temperature ... which is actually not unpleasant, but not an accurate color rendition of the scene especially the dress. The first panel shows it "as shot".</p>

<p>The second panel shows a White Balance correction using the eye-dropper. It demonstrates the effect of overly warm shots on exposure. The scene is now underexposed, and the blue cast on foreground subjects from the flash is more apparent.</p>

<p>The third panel shows application of the custom brush feature in LR that allows you to selectively alter color cast/temperature, contrast, saturation etc. It is one of the more sophisticated tools in LR and takes a bit to master, but when mastered, provides endless ability to locally adjust anything in the scene. I used it to restore the warm cast to the skin (see Orange cast color selection box), and to remove any residual color cast to the dress.</p>

<p>Lightroom is far more sophisticated than most users suspect.</p>

<p> </p><div></div>

<p>Here is a bigger rendition of the last panel above:</p>

<p> </p><div></div>

<p>Marc - Thanks for your comments. I use the adjustment tool in LR all the time. Although one can use it, as you did, to selectively color certain areas (eg, the bride's skin), unfortunately, it does not, per se, provide an actual white balance adjustment/slider. You can fake it, to some extent, using the colorize swatch, but IMHO, the results of this are pretty far from a real white balance adjustment.</p>

<p>Tom M</p>

<p>Depends on your knowledge of the color wheel and how opposites correct any given color ... or what you want the scene to creatively look like ... as opposed to being technically AWB color correct everywhere in the scene Tom ... which I can also do if I want because the colorized swatch panel with color picker is real time, infinitely variable and the " adjustment slider" for flow and density is located just below for refinements.</p>

<p>So, I don't consider it "Faking It" at all ... and I don't have to revert back to a less versatile RAW processor to do it. LR is the best RAW Processor I've ever used because you never have to leave it or process out an image to use a third party program like Define 2, Nik B&W, or even Photoshop ... everything stays in the LR library in order. It has cut my processing time in half and continues to get faster and more versatile with every new release. </p>

<p>But, to each his or her own.</p>

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<p>Have to agree with Tom on this one. And in the example that Marc used the problem with mixed lighting actually comes from not having the on/off camera flashes gelled to ambient. But some people like the heavy orange cast on the background so horses for courses.</p>

<p>PS. Marc, a color correction is not at all a white balance correction, especially when it comes to overexposed areas. Best thing would be if they put localized white balance correction in LR then everybody would be happy :-)</p>

<p>BTW, I know why Lightroom doesn't have local white balance (yet). It's because it is very tricky to implement. White balancing a raw image is done on the raw data before demosaicing. All the local adjustments are done as the final steps when the image internally is more like a tiff than a raw file. So to make white balance locally adjustable the LR team have to remodel the entire raw conversion engine.</p>

 

<p>Thanks for all suggestions. Will try it out in LR despites I'm not that handy.<br>

I can't upload the picture without getting permission from the organizer. I thought I can do some camera setup to avoid different color temp. on picture. In my practice, the organizer asked me to upload digital files to their notebook right after the event.</p>

<blockquote>

<p>without using flash</p>

</blockquote>

<p>bad luck, otherwise you could have done the gel and white balance trick.</p>

<p>In hindsight, would oloneo relight have worked?</p>

<p>Marc, when you look at the issue of color correction in more detail, you will see that the oft-stated comment, <em>"...and how opposites correct any given color..."</em>, while correct in a general sense, is dreadfully inadequate when it comes to actually doing the work and getting good results.</p>

<p>For example, in a thread in early May, someone thought he accidentally used a very pale cc05 cc filter, and was asking for a formulaic way to correct it. This should be a trivial problem, right? Just simulate in software a cc05 that's half-way around the color wheel. Well, it may or may not be that easy. In a post dated, May 04, 2011; 02:43 a.m. (EST), I pointed out that three different color correction methods (all relying on "the other side of the color wheel" general concept) all produce very different results. The exact same principle applies to the color tint patch in the adjustment brush in LR3. Think of the general problem of color correction as, at minimum, a 15 parameter problem, ie, in the "Levels" dialog box, each of the three colors has five sliders. In these terms, do you know exactly how the color tint in the LR adjustment brush really does its thing?</p>

<p>To clearly demonstrate why I feel that the color tint patch is not a true color temperature correction technique, but can be used to "fake" it, start with an image with nearly perfect color, say, a standard, outdoor snapshot in good lighting. Import it into LR, but incorrectly set the color temp to make it look extremely blue. Export the resulting blue image as a 16 bit per channel TIF with a different name, and then re-import that file into LR and try to fix the intentionally incorrect color.</p>

<p>If you use the standard color temperature sliders, it's trivial to make the correction, and the results are almost always very good with no strangely colored shadows or hilights. </p>

<p>Next, try to use your color tint / adjustment brush technique on the overly blue image. If the intentionally introduced color error is too large, you will find that you can't correct for it with one application of the color tint brush (even with a fully saturated color patch), and even if you use two applications of the brush, you will likely wind up with strange colors in the shadow and highlight areas. Even worse, if you make the mistake of applying any tonal corrections to the image before or during application of the brush, the color problems get infinitely worse.</p>

<p>This behavior is in contradistinction to the color temp sliders or any other "real" color temp correction technique. In these, the color correction is almost completely independent of tonality and other global image tweaks.</p>

<p>The last reason I'll mention for why I don't consider the color tint patch a true color temp correction method is very simple. It isn't calibrated. Using this method, everything is by eye. In contrast, I know exactly the color temperature of my hot lights, ordinary room incandescent lights, mid-day sun, my strobes, etc. I don't want to have to diddle around to get the right correction. I want to dial it in and know that for controlled / standard lighting situations, the correction will work. I don't need anything slowing me down.</p>

<p>Finally, I should say that I agree whole-heartedly with your last comment, <em>"... It has cut my processing time in half and continues to get faster and more versatile with every new release. ..."</em>. Around here, you're preaching to the choir on this one and your comment about becoming more familiar with the color wheel. :-)</p>

<p>Cheers,</p>

<p>Tom M</p>

 

<p>Indraneel, what is, <em>"oloneo relight"</em>?</p>

<p>Tom M</p>

<p>Tom, here's a link. I don't know too much about it, tried it once, liked it, but not my way of working.<br>

<a href="http://www.oloneo.com/en/page/photoengine/hdr-relight.html">http://www.oloneo.com/en/page/photoengine/hdr-relight.html</a></p>

<p>You take shots in each of the different types of lightings and mix the lights/shots in post. Works very well for static subjects, but I was wondering if anyone tried it with non static subjects too (with some creativity).</p>

<p>Indraneel, thank you for the info. I had never heard of it before.</p>

<p>I looked at the link very quickly. It looks interesting, but I'm just heading out the door, so will study it more closely tonight.</p>

<p>Best regards,</p>

<p>Tom M</p>

<p>Understood Tom. </p>

<p>My example wasn't to say that you empirically take the opposite in the color wheel ... but to just know the starting basics. The color patch in Light Room is infinitely variable and you can apply it to a select area and see it in real time on the photo ... sometimes the most pleasant visual correction isn't a precise color wheel opposite.</p>

<p>However, I do grasp that selective color temp correction could be a real benefit for correcting mixed light.</p>

<p>For Medium Format work, I use Phocus software which has a different take on it ... a system of real color picker and wheel that shows that exact color you selected and allows both hue and shade corrections. </p>

<p>there is no white balance tool to balance a local area the same as overall. Marc's directions are great.</p>

<p>Another would be to make a virtual copy for as many areas as you want a custom balance for, correct each seperate open as layers in photoshop and blend them togeher. <br>

For the purpose of a newsletter, just do the best you can for the face and don't worry about the rest.</p>

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