how to correct incredible color cast

<p>This is a Photomatix exposure fusion (not HDR) composite of 3 exposures. I know I was going to get a crazy color cast so I put that white card on the floor hoping that clicking on it with levels/curves white dropper would fix the color. It didn't. It blew out all the highlights and a strange color cast remained. The walls are actually a neutral, almost off-white color. There's almost no light hitting them. They are only 'lit' by virtue of a long exposure.<br /> I know the next thing I'll do is try a gray card instead and of course I can add real lighting to really light up the place but I want to know how to use Photoshop CS6 or LR3 (but probably <acronym title="Photoshop">PS</acronym>) to work with an extreme color cast problem.<br /> Please help.<br /> Thanks,</p><div></div>

<p>Use the white balance dropper in CS6 or LR. The light spot on the very left above and to the left of the lamp works just fine. You have mixed lighting so it's not going to be just right everywhere, but it took me all of two seconds to take out most of the cast.</p>

<p>I didn't try anything fancy at all, but here is the image after loading it in ACR and simply using the "auto" for color balance. Touch of exposure control.</p><div></div>

<p>Using the white balance dropper doesn't give the blue-ish cast that JDM's version does. It will probably look better with a small exposure increase, maybe with the window masked so the exposure doesn't change on the outside area.</p><div></div>

<p>Hmm. Exposure fusion is not supposed to alter colors much. I have a different hunch about what may be going on:</p>

<blockquote>

<p>The walls are actually a neutral, almost off-white color. There's almost no light hitting them. They are only 'lit' by virtue of a long exposure.</p>

</blockquote>

<p>I do a bit of night photography, and one of the things one runs into there is that the color cast from a long exposure under very low light is often quite different--and often much more intense--than what one gets with more normal lighting. For example, skies often turn out a very vivid, almost artificial-looking blue. I've assumed that it is a function of the color mix of the light at those low levels, but maybe it is the sensor's behavior under those conditions. <br>

<br />I'll post an example below. It's a 2-minute exposure at about 9:30 at night. It looks like I played with PP to jack up the saturation to unnatural levels, but I didn't. My recollection is that it has only a modest vibrance adjustment.</p>

<p>This doesn't help fix the problem, but it may help explain what happened.</p>

<p><img src="http://dkoretz.smugmug.com/Nature/Outdoors/i-w2Gq9Kb/0/L/MG1827-L.jpg" alt="" /></p>

<p>I tried Jeff's method with the white dropper by the lamp, fill light, increased exposure a touch then desaturated the yellows and oranges, all in LR and it came out pretty good.<br>

Thanks,</p>

<p>Your interior lighting is a mix of yellow red and somewhat blue. The light outside is blue. Correct for one and the other will creep up. You're looking at more of a removal of a color cast than adjusting the entire image's white balance. Using a flash would even things out a lot. The flash is daylight balanced (usually, depending on the flash).</p>

<p>Dan, Yes, you are correct about the lighting. But there are times when I'm asked to shoot a room and the only tool I'll have is blending exposures then correcting for color later, hence this exercise.<br>

Thanks</p>

<p>Wow, Bob, that was a tough one. I decided to try to concentrate on the interior of the room, but let the bluish cast (mostly reflections) from the window stay because I thought that looked somewhat realistic.</p>

<p>I started with ACR tweaks (both the eyedropper and tweaking the saturation and luminosities of individual colors). I then brought the image into PS, cleaned up the patchy noise that was creeping in (because of all the processing), painted in some of the regions of blown (or nearly-blown) channels, and further pulled back on the yellow color cast. Then, a brought in a new copy of the image from ACR, xcept this time, I concentrated on trying to recover as much as possible from the window. I then pasted the window area onto the stack that I had been working on.</p>

<p>My conclusion: A royal PITA with very little to show for the effort. Lesson: Always have a few little shoe mount flashes and gels in your camera bag, and either place them judiciously around the room, or use one of them to paint the room with light (separate exposures for each flash) and combine them in PP with other exposures for ambient and window light.</p>

<p>Tom M</p><div></div>

<p>In lighting like this, most of the software auto correct attempts look like hack jobs.</p>

<p>Better to go in manually using RGB CYM sliders.</p>

<p>The original shot looks almost correct - correction should be along the Red-Cyan or Green-Magenta axis.<br>

<br /> The final image should look warm.<br>

<br /> The cool versions above look like hack jobs.</p>

<blockquote>

<p>I tried Jeff's method with the white dropper by the lamp, fill light, increased exposure a touch then desaturated the yellows ....<br>

</p>

</blockquote>

<p>Ditto -- first thing I thought of and worked great (just the white balance and the YLW desat). I think the exposure is perfect, except for the window outside.</p>

<p>Got it guys, with all your help.<br />Reshot today with a gray card instead. clicking on it in LR was way better. Then went in and Desaturated some remaining yellow/orange cast and also desaturated the blues.<br />Then, I made a took one of the really low outside exposures, made sure the WB was set to daylight, layed in on top of the corrected version, masked it and painted back in the corrected images, leaving the window exposures alone. Also made sure that the trees from outside reflected on the coffee table and TV screen.<br />Lastly, I did some dodging with the brush set to 'overlay', a trick a photoretoucher showed me.<br>

I think the final is pretty satifsying.<br>

<br />Thanks for all the help, Bob</p><div></div>

<p><em>"The original shot looks almost correct - correction should be along the Red-Cyan or Green-Magenta axis. ... The cool versions above look like hack jobs."</em></p>

<p>Andre, as the saying goes, talk is cheap. Several people went out on a limb and posted the actual results of their efforts, leaving them no wiggle room, and you twice called them, "hacks". </p>

<p>In contrast, you posted nothing more than a single, extremely general suggestion. It must have taken you all of 10 seconds to write that statement. In this field, the devil is in the details, so why don't you put your money where your mouth is, post your own tweaked version with a description of the method you used, and we'll see how good it looks and how much effort you had to expend to get to that point.</p>

<p>Tom M</p>

<p>Bob, that looks good to me, but beware, it looks suspiciously cool, so maybe it's just another one of those <em>"hacks"</em> ;-)</p>

<p>Tom</p>

<p>Bob, I'm VERY impressed with your end result! It's light-years better than anything that I was able to accomplish with my traditional approach of using color sliders, selective color sliders and exposure changes. Almost every single aspect of the image looks pretty natural to me.</p>

<p>Questions:<br /> 1. Did you place the graycard in the same place that you originally had the white card? If not, where was it?<br /> 2. How much of the correction was accomplish by JUST clicking on the graycard vs all of the other corrections you added afterward?<br /> 3. Could you possibly throw up a version of the image showing us how it looked after having ONLY clicked on the graycard? I'd like to compare that to your end result after having done all of the other corrections.</p>

<p>Again, great job!</p>

<p><br /> Thanks!</p>

<p>Thanks Randy,<br>

The image doesn't have as much magenta in LR but I see that it is there. Darn.<br>

Answers to your questions:<br /><br />1. Gray card was put facing cam on the black floor pillows. Cloned out.<br />2. See photos for straight blend of 3 exposures and the single click on the gray card version, better, but still bluish tint.<br /><br /></p><div></div>

<p>And here is the click on the gray card.</p><div></div>

<p>Thanks Bob.</p>

<p>You're right Tom.<br /> I tried correcting the original shot using my own suggestion and it came out a hack job too.<br /> This from the original re shhot, I corrected using the U-Point tool in Capture Nikon NX2. It looks more natural than the "clicked on grey card" - I think. </p>

<p>PS: I didnt do anything with the grey card. i pointed the control points on the white walls and removed the warm cast with the "white" walls as a reference.</p>

<p>I use that tool alot, in compliment with Photshop color balance and curves for my color correction.</p><div></div>

<p>My attempt still has a veil of "Listerine colored" color cast in the bottom half of the photo one can corrected in Photoshop.</p>

<p>Thanks, Andre. It was surprisingly more difficult than one might initially suspect, especially if you try to take into account the OP's comment that the walls were nearly colorless.</p>

<p>BTW, when you suggested a correction along the Red-Cyan or Green-Magenta axes, I thought of many ways to do this, all with somewhat different results and certainly with different (unintended) side effects in a mixed lighting situation like this. For example in ACR or LR, you could simply move the WB sliders. One could also use the hue/saturation/brightness adjustment and play with those controls. In PS, one could use a solid color layer set to "color" blend mode, one could use their "Photo Filters", or many other tricks. What did you have in mind?</p>

<p>Tom M</p>

<p>Andre,<br>

OK, I'm glad I stopped back here because now your version is my new favorite as far as looking natural.</p>

<p>I'm not familiar with the software that you used.</p>

<p>1. Is it strictly for Nikon users?<br>

2. Did you accomplish your version is short order without using any selective changes?</p>

<p>Nikon Capture NX2 works with JPEGs TIFFs Nikon NEF (raw) files. Using The color control point is very quick. <br>

Its action is similar to the Targeted Adjustment Tool in Photoshop Camera Raw.</p>

<p>Thanks Andre !</p>

<p>Bob,<br>

Maybe I'm missing something really simple here but when you say "The walls are actually a neutral, almost off-white color. There's almost no light hitting them. They are only 'lit' by virtue of a long exposure." the "almost no light" that IS illuminating them (they're not glowing from within) is the tungsten light from the lamps, which is yellow/red (thank god they weren't using CFL bulbs!). So to the human eye and the sensor, they will appear yellow. This is not necessarily bad since most people like a "warm" room. Andre's last fix looks the best because even though the walls are off-white, the floor is washed with the yellower light from the lamps.<br>

<br />Are these real estate pictures? If so, how is that business - the RE photo business, not real estate (we know how that's going).</p>