cgardner Offline Upload & Sell: Off
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The yellow problem with the image you posted is caused by clipping the red channel in the skin due to overexposure. Overexposure of around 1/3 stop will cause skin highlights to start to clip, first in red the dominant color in skin in an RGB file. That in turn gives the skin the odd flat waxy yellow look you are seeing and apparently reacting to. The OOC image is neutral in the non-clippping highlights shown below...
Opening the image in Levels, holding down the alt key (opt on Macs) then clicking the highlight slider reveals any clipping channels. Here's your OOC original version...
http://super.nova.org/EDITS/ClippingReds1.jpg
When faces clip that much in red it indicates exposure is over by about 2/3 stop. The reds in skin shouldn't clip until the highlight slider is moved left, forcing clipping in a normal image, to around 240, 15 units under clipping whites. If made any eye dropper based color correction on those clipping areas they would incorrect, skewed by the clipping.
Checking the non-clippping whites in the image with the info eyedropper I find not perfect but not far off neutral in most:
http://super.nova.org/EDITS/ClippingReds2.jpg
Using the levels eyedropper to snap color to neutral I got this result. I reset the highlight target to 250,250,250 (solid white vs. 255 clipping white) and clicked on the boys collar as indicated:
http://super.nova.org/EDITS/ClippingReds3.jpg
But the click correction on the non-clipping highlight can't fix the blown red channel / yellow waxy look in the blown highlights. You simply need to control exposure better at capture.
As for color management? All you really need is a Kodak R-27 Gray Card Kit, $19.95 at B&H:
http://www.bhphotovideo.com/bnh/controller/home?O=&sku=27715&Q=&is=REG&A=details
This proof sheet of a speedlite portrait session shows how I use mine:
http://super.nova.org/TP/MAGLens.jpg
In frame one I shot the card filling the center circle of the viewfinder. That's why you need a larger card. I put the camera in Daylight WB when making this shot.
After setting Custom WB I shot the card again. By comparing the before (Daylight WB) and after (Custom WB) I can gauge how different in color from a daylight WB the light is. The second shot is a editing reference. The card should be and usually is R=G=B when checked with the eyedroppers.
The third shot is an exposure check. I've used the same manual speedlight set-up for 40 years so the exposure is usually correct, as it was here, but I check for clipping anyway using a white towel which shows up well in the camera clipping warning. When it is just barely starting to clip in the camera playback I know from experience using it the RAW file is just where I want it, under clipping. WB and exposure optimal I knocked out the portraits, pose for my shot someone else shot, and was eating the pizza all in about 15 min. In PP I didn't mess with the color because I knew it was correct out of the camera.
The towel gimmick a simple way to avoid the the clipping highlights problem -- the clipping warning in the camera becomes an idiot light, showing when and where clipping highlights are occurring. Get the towel exposed accurately and lighting ratio recording the full range of detail and all the faces and all the other content will look "normal" as seen by eye.
BTW - Checking the shadows of your shot with the alt+click Levels eye dropper trick I see they are clipping also, an indication the shot is under filled in the shadows. The solution to that problem set your lights starting with a black target on a light stand where the subjects will be (a black towel ). Start with just your fill on and raise it until you see detail in the shadows test object. Turn on the key light and raise it until you see the highlighted parts of the white towel placed on the stand barely start to clip. Bingo! You arrive at perfect exposure and a perfect match of scene range to sensor in two easy steps.
With the feedback provided by the camera all that is needed for complete control of exposure and color balance are:
1) A white towel or similar textured object for evaluating clipping / loss of detail in highlights visually.
2) A black towel or similar textured object for evaluating clipping / loss of detail in shadows visually.
3) A $20 Kodak Gray Card. In November 2010 Kodak partnered with X-Rite to revamp the card kit and the card is now MulSel 18% gray. Previously the cards were also neutral, and actually made by Tiffen. More expensive plastic cards will be more durable over the long haul but will not do the job any better.
If you can record a full range of tone and set Custom WB in the camera there will be nothing to adjust on screen because it will be correct "by the numbers" out of camera. If you have a subject hold a gray card in a test shot when you view it on the computer it calibrates your color perception to trust it "by the numbers" (BTN) as your evaluation baseline because it will be R=G=B when measured with the eye dropper tool.
http://super.nova.org/TP/PatrickGrayCard.jpg
Then from that baseline in the RAW editor you can tweek the color from BTN neutral to whatever warm/cool bias you feel the shot needs to convey the mood of of the subject or environment. For example for outdoor shots in the summer I might nudge the color a bit warmer yellow, but for a winter shot I might make it cooler bluish to convey the fact its cold. So the BTN color balance using the gray card is just an objective starting point, not the end destination for the color, but for most shots BTN neutral looks "normal".
The color checker? The colors in the chart have no role is setting WB, but serve as a visual roadmap for how different colors change when styles are used or color balance changed manually. For example here is a RAW shot of my color checked with different styles applied...
http://super.nova.org/TP/Styles480sRGB.jpg
That gave me a more objective understanding of how the styles affected specific colors better than if I simply applied them to camera images.
If you have a MacBeth or similar target and have your subject hold it in a test shot, then work that test shot all the way through to printing with your normal workflow you'll have a better idea how the color will change from capture, editing and printing. At each step you can compare the results with the actual target you shot.
What will be the "best" color? Whatever makes each photo look most normal, despite all the physical limitations of the reproduction process.
Apart from exposure setting the clipping in your file is a result of your lighting strategy. Butterfly lighting works better for groups because it puts the same intensity and pattern of light on all the faces. It is also more flattering than the horizontally crossed lighting pattern it appears you used.
You may find these tutorials of mine helpful:
http://photo.nova.org/DigitalColor/
http://photo.nova.org/GrayCard/
http://photo.nova.org/ColorManagement/
http://photo.nova.org/Groups/
Edited on Nov 16, 2011 at 12:57 PM · View previous versions
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