How do I correct skin tones?
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如何才能调出来pro拍出来的那种skin tune
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How do I correct skin tones?
Updated: 08/25/2014
First, the bad news: 99% of all customer
complaints about printing are related to skin tones. And it's the
subject most likely to make photographers weak in the knees.
Now the good news: Unlike expressions and poses, which are a matter
of taste, there's a simple way to measure skin tones and feel confident
they're safely in range.
When it comes to skin, however, it's about a pleasing tone. The customer wants to look good, and she's allergic to red.
Then, click on the eyedropper tool. If you hover the eyedropper over areas of skin, you'll see the color values in Red, Green, Blue ( RGB—monitor display colors) and in Cyan, Magenta, Yellow, blacK (CMYK—print ink colors).
Stay with us! It's dead simple: Ignore RGB.
90% of all you need to know is that you can never let the yellow % fall below magenta % on anyone's skin unless you're trying to show sunburn.
Your camera may capture images with less yellow than magenta in skin; unfortunately, they won't print without customers complaining if you print them without color correction. Nor will magazines accept them for publication.
A fair-skinned pinkish baby could be as light as 15% magenta, 16% yellow. Most Caucasians fall in the range of 5%–20% more yellow than magenta. A fair-skinned Caucasian adult could be as low as 20% magenta, 25% yellow. A bronzed Caucasian could be as high as 45% magenta, 62% yellow. We find it's easy to oversaturate African-American skin, so be careful there. Yellow and magenta values should be fairly close. We agree with Lee Varis, in that you might find a yellow bias in African-American skin, which will not look good in print.
Asian and Hispanic skin will typically have 10%–20% higher yellow than magenta.
These three photos have the same yellow and magenta values, only cyan changes. Cyan is 24% of magenta on the left (slightly low), 40% in the center, and 60% on the right (too high).
If you use Lightroom, you can download some of these free, skin-specific presets from OnOne. Want to discuss more with the experts? Head over to our Finishing School forum on Dgrin.
Yes, and here's how:
Go to Image > Adjustments > Levels. A small window will appear like the one below. Choose the blue channel from the Channel drop-down menu. For input levels, change the center one to 0.90. You'll see your image warm up. (For really red images, you could go to 0.85.) Click OK.
Go to Image > Adjustments > Hue/Saturation. Choose the red
channel from the dropdown-down menu. Shift the slider to -7. Click OK.
That's all there is to it.
Go to Image > Mode > CMYK Color.
Now go to Image > Adjustments > Curves. The small window you see below will come up. Choose the yellow channel.
Choose a representative spot of skin, such as the forehead. Move the eyedropper to that patch of skin, hold down Ctrl and Shift (Shift-Command on Mac), and then click your mouse on the skin. The point you see on the line, below, will appear.
(You can configure the eyedropper to sample a 5x5 or 3x3 pixel area to make it representative.)
Even though this shot was taken with a professional camera and good studio lights, with yellow at 18% and magenta at 22%, Kim is bound to think she looks too pale and too pink.
We'll type 30% into the place for output. Then we'll switch to the magenta channel in the drop-down and type 24% in the space for output. Finally, we type 8% for cyan output (33% of the magenta value).
How did we choose those values? They're typical for fair-skinned Caucasians and not too far from the original shot.
Finally, go to Image > Mode > RGB Color. Save.
Thanks to Dan Margulis and Lee Varis for much of the wisdom behind the curves portion of this help section.
------------------------------------------------------------------------------------------------------------------It's Not About Color Accuracy
You're probably shocked to read that headline from the company that provides calibration prints and ICC profiles—and takes pride in offering you the option to print without color correction.When it comes to skin, however, it's about a pleasing tone. The customer wants to look good, and she's allergic to red.
Measuring Colors
If you're using Photoshop, go to Window > Info to bring up the Info window you see below.Stay with us! It's dead simple: Ignore RGB.
90% of all you need to know is that you can never let the yellow % fall below magenta % on anyone's skin unless you're trying to show sunburn.
Your camera may capture images with less yellow than magenta in skin; unfortunately, they won't print without customers complaining if you print them without color correction. Nor will magazines accept them for publication.
Reasonable Magenta and Yellow Values
 C: 19% M: 33% Y:50% |
 C: 22% M:44% Y:57% |
C: 13% M:28% Y:33%
|
A fair-skinned pinkish baby could be as light as 15% magenta, 16% yellow. Most Caucasians fall in the range of 5%–20% more yellow than magenta. A fair-skinned Caucasian adult could be as low as 20% magenta, 25% yellow. A bronzed Caucasian could be as high as 45% magenta, 62% yellow. We find it's easy to oversaturate African-American skin, so be careful there. Yellow and magenta values should be fairly close. We agree with Lee Varis, in that you might find a yellow bias in African-American skin, which will not look good in print.
Asian and Hispanic skin will typically have 10%–20% higher yellow than magenta.
Too Much Color
In the days of film, we used saturated films like Fuji Velvia for landscapes but less-saturated films for portraits. No one wants their face to go nuclear. If magenta is getting toward 50%, beware of the well-done look.The Surprising Power of Cyan
On pleasing photos, cyan usually falls between 30%–50% of the magenta value. Less than 30% of magenta makes sunburn; more than 50% of magenta makes makes them ghostly blue.These three photos have the same yellow and magenta values, only cyan changes. Cyan is 24% of magenta on the left (slightly low), 40% in the center, and 60% on the right (too high).
 C: 6% M: 25% Y: 30% |
 C: 10% M: 25% Y: 30% |
 C: 15% M: 25% Y: 30% |
Okay, Tell Me How to Fix My Photos the Easy Way!
90% of all skin tone complaints come from magenta values being higher than yellow. It's so common that consumer labs rarely allow you to print without color correction. SmugMug gives you the choice: You can print your photos without any adjustments, or you can easily enable our world-class color correction with a click.If you use Lightroom, you can download some of these free, skin-specific presets from OnOne. Want to discuss more with the experts? Head over to our Finishing School forum on Dgrin.
Is It Easy to Do with Photoshop?
Go to Image > Adjustments > Levels. A small window will appear like the one below. Choose the blue channel from the Channel drop-down menu. For input levels, change the center one to 0.90. You'll see your image warm up. (For really red images, you could go to 0.85.) Click OK.
That's all there is to it.
Should I Ask About the Less Easy Way to Do It?
Yes, because it's also easy, and you'll delight people with your skin tone mastery.Go to Image > Mode > CMYK Color.
Now go to Image > Adjustments > Curves. The small window you see below will come up. Choose the yellow channel.
Choose a representative spot of skin, such as the forehead. Move the eyedropper to that patch of skin, hold down Ctrl and Shift (Shift-Command on Mac), and then click your mouse on the skin. The point you see on the line, below, will appear.
Even though this shot was taken with a professional camera and good studio lights, with yellow at 18% and magenta at 22%, Kim is bound to think she looks too pale and too pink.
We'll type 30% into the place for output. Then we'll switch to the magenta channel in the drop-down and type 24% in the space for output. Finally, we type 8% for cyan output (33% of the magenta value).
How did we choose those values? They're typical for fair-skinned Caucasians and not too far from the original shot.
Finally, go to Image > Mode > RGB Color. Save.
 Unadjusted C: 6% M:22% Y:18% |
 Tanning Salon C: 7% M:20% Y:24% |
 CMYK Curves C: 8% M:24% Y:30% |
Red Spots?
If you still have red issues, we have help.Thanks to Dan Margulis and Lee Varis for much of the wisdom behind the curves portion of this help section.
发信人: bangbing (bangbing), 信区: PhotoGear
标 题: Re: 如何才能调出来pro拍出来的那种skin tune
发信站: BBS 未名空间站 (Fri Aug 29 14:25:23 2014, 美东)
我不是pro，所以无法告诉你pro是怎么做的。但就我个人的经验来说，白平衡在大部分
室外情况下是不需要手动设置的。靠自动或者在自动的基础上微调就行了。室外的前期
肤色如何，一大部分取决于光的质量。
而室内则往往需要做一些额外的校正，对自己后期调肤色不是很有信心，或者后期想省
事的，一般还是拍色卡做参照比较保险。当然也有pro手动设置白平衡的，但这个需要
的经验就多了。对于那种光线杂乱变化很快的场景，比如舞厅，自动白平衡往往会非常
不准，这个时候可以用闪光来overpower一部分人脸的光，从而使白平衡不会偏得太离
谱。另外还有一个常见的误区就是认为人的肤色一定要白才是正的，实际上再很多场景
下，受环境光影响有一些轻微的color casting才反而显得更自然。
至于后期的肤色调整，这个完全是看个人对色彩的审美感觉了，白平衡本来也就是个主
观的东西，没有绝对的正确。但是还是那句话，人脸让人第一眼感觉的所谓“skin
tone"拍出来是否professional，很多时候不光是由调色决定的。比如Danny有些室内照
片的人脸的肤色，并不一严格意义上的标准，也有人说偏黄。但为什么整体看上去还是
很和谐，原因无非就是第一光质比较好，第二脸部的偏色符合当时环境的color
casting，并且不过份。
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发信人: bangbing (bangbing), 信区: PhotoGear
标 题: Re: 如何才能调出来pro拍出来的那种skin tune
发信站: BBS 未名空间站 (Fri Aug 29 16:47:31 2014, 美东)
这类文章我几年前看过，包括还有如何在ps里用曲线工具设置white/grey/black point
的方法校准白平衡。实践下来我觉得这些技术、准则能够在一些情况下提供一个不错的
调整起始点，和培养一些对肤色调整的感觉，但不是放之四海而皆准的。
如果了解过那些傻瓜机常用的skin detection technology的话会知道不同人的正常肤
色在不同光线情况下，是存在于一个不小的色域范围内的，因此在数学上讲只要在这个
范围内都是”合理“的，而很多准则比如几种颜色的比例其实也都是heuristic的，并
不代表结果会一定visually pleasing。所以最终调整得如何还是和摄影师对色彩的感
觉很有关系，仍然不可避免的是一个经验主义的任务。当然这些具体的技巧提供了一个
大方向。
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