Color Correction - Skin Tones Part 2

In the last digital photography tutorial I wrote about how to correct skin tones using curves on a duplicate layer using the color blending mode. The last photo (in the previous post) consisted of a person in a photo where the color in the whole image had to be considered during the correcting. This next method of color correction for skin tones makes use of masks to change the color. I am considering the different parts and shapes within the photo. The model, the clothes and the surrounding background. I can change the models skin tone, make sure the clothes are the right matching color and clean up the background (or change the color if it emphasizes my subject better). Since this tutorial is about skin tones that is what I will focus on after correcting some of the photo through curves.


If I has a swatch for the skirt, I could match that color and hope that the whole photo will fall around the color correction properly. But I do not. If it is a Brown skirt, then the LAB numbers of 34, 16, 6 are telling me it is a Reddish Yellow skirt and not a brown skirt. The strobe cover in the top right measures to a neutral Black.

You can color correct the whole image with curves or use the masking method I am going to show you below. I wanted to change the skirt color because I was not comfortable with it being a Reddish yellow instead of a Brown (Yellowish Red). With these curves, I changed the color of the overall image, specifically added Cyan to the models face and made the skirt a Brown color (which I think it should be).

Which gave me this color corrected photo with a Brown skirt and a more pleasing skin tone color. But we want to go further with the models skin tone. We want to control exactly how it is going to print via layering a more typical color. Now to masking the skin tone color correction.

Skin Tones in Caucasians that are light can be considered C10, M27, Y32. So this is the color I am going to use for the photo below. Where did I get those numbers? From experience, from messing up plenty of times, from studying the color of skin tones in different people for many years. There are plenty of skin tone swatches you can download on the internet if you do a search. In the photo below, I see there is too much red and yellow in the skin color.

At this point you want to make the foreground color in Photoshop the light skin tone color I suggested before. Or save the swatch below, click on it with the eye dropper tool and set the foreground color that way.

Now goto -->> Layer -->> New Fill Layer -->> Solid Color


Change the mode to Color or Hue (blending mode) and hit OK. The pick a solid color display will come open. You can change what color you want with this or keep the one we chose. Hit OK, and the whole image has that color as a color cast. Now open the layers list,make sure the mask is selected, and fill it with black to block the skin tone color. Now take a white brush, at 100% opacity and paint in the skin tone color where you want it to show through. Then toggle the opacity of the layer depending on how much of the effect you want to show through (also decide if Hue or Color blending is better). I chose 45% opacity in color mode to cut down on some of the problematic Yellow color around her skin. The photos below are before and after the painted on skin tone color correct.

The skin tone mask cut down on the variety of different colors in the models skin and created a much more uniform base with which to work artistic magic with. Look at the palm of her hand or parts of the side of her face in the original image and the new color corrected skin tone photo. The yellow color cast has been eliminated. There was also a point on her elbow that had more magenta than yellow and now it is within a skin tone parameter. At this point you can alter the mask in certain areas to let the original color show through more or create another layer with a solid color, essentially painting like an artist in front of a canvas. Go as far as you want as an artist or leave it as natural as you like. Use color and tone masks to highlight facial areas and minimize other parts. You are now the makeup artist. I have given you the Photoshop technique that fashion magazines use to make these changes to the skin tone. It is up to you how far you want to go.

Skin tone color correction is one of the hardest parts of post processing. So give it time. This was a minor example just to show the technique of masking skin tones for color correction. 

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Color Correcting Skin Tones in Digital Photography

When you look at a photo with a person as the subject, you really want the skin tones to be a believable, or better, a correct color. The established method for reading skin tone colors is through the CMYK (Cyan, Magenta, Yellow, Black) color space. CMYK is the opposite, or opposing colors of RGB (Red, Green, Blue). If you lessen the color Blue somehow (through curves, selective color, etc.) you will be adding Yellow. The same is true for Green which has an opposing color of Magenta. That leaves the color Red having a the same effect on Cyan. If you increase Red you take away Cyan.

There is no CORRECT exact skin tone color that you can plug into a photo and get perfect results every time. It just doesn't work that way. But there is a basic skin tone color/hue which is Yellowish Red. To get a Yellowish Red skin tone the following color recipe should be observed.

CMYK - Yellow highest, Cyan lowest, Magenta closer to Yellow.
RGB - Blue lowest, Red highest, Green Closer to Blue.
LAB - A and B positive, B highest, A more than half as high.

The rules above create the color Yellowish Red. And all people have this combination (except for really pale infants and maybe some really pale people. They may have a slightly higher magenta than yellow). There are some other instances where this rule may be broken, like someone who has just exercised may exhibit a more magenta look, or have a bad sunburn, because they have a red face. But these instances are very few and draw attention to the person in the photo in what is considered a bad way . We want to see healthy skin tones and we have an unconscious idea of what that color is when viewing a photo.

When color correcting skin tones in a photo where there are other objects, you have to consider and measure the interrelated parts of the. We want the skin tones to be believable but not throw off the rest of the photo. In the photo below, the cement and the skin are in the same tonal range, so if you change one (without masking) then you are going to change the other. You have to be careful how one effects the other when changing color.

The photo above looks good, but there is some muddiness in the color. The difficulty of this photo is that there are NO know colors in the whole photo. We can make some guesses, like the ladies shirt in the background being white, and the sign in the back being black. But they might not be be pure white and black. Using skin tones in this instance as a KNOWN color helps us down the color correcting road very well. If we get the skin tone into a better range, a more pure Yellow Red, then we can get a better idea of what might need to be our neutral Blacks and Whites in the photo. When yu get one known color in a proper range the rest of the photo should fall into place.

I would say there is slightly too much Cyan according to the skin tone numbers in the main subject. The skin tone CMYK also says that Magenta is too far away from Yellow (color point 1). It is a common rule that you should not use a persons face to measure skin tone. You don't use the face because the person (especially women) will/may have makeup on. Men have beard lines that may change the color reading of the skin tone. The only lit part of my central subject is his face, so I broke that rule here, found his beard line and used the side of his face where the beard line did not affect the reading as my measuring point (color point 1).

As I placed points around the photo, I notice that the ladies white shirt has too much blue (The upper tonal range). This is common in digital photography and I see it in wedding photography very often, uncorrected too (so the bride picked a BLUE dress).

I decided to add a slight bit of Red to the mans face (lowering Cyan in CMYK) and make my Blue curve the main tool of color correction since it is the most contaminating color in most of the photo. Below you see the photo with the color adjustments on a duplicate layer in color mode, the new measurements and the Blue curve that got me there.

I made the shirt white with a rather dramatic color curve in the blue which put many other objects in the photo into perspective. I also took a little bit of Blue out of the lower half of the curve (the shadow side of the curve) to keep the sign neutral behind the subject. By adding some Blue in the midtone area of the curve, I lessened the Yellow (CMYK) in the skin tones, bringing it closer to my preferred magenta number and eliminated much of the "muddiness" in the colors of the photo. A very slight increase in the Red curve directed at the skin tones and my color correcting is finished.

Is there a big difference? After you color correct 100,000+ photos on a calibrated monitor, you will easily see a difference which is the main point of color correcting. When there is a slight color cast like the photo above, it makes all the colors a little less vibrant. It muddies everything with a slight gray cast.

The above photo is rather flat and the midtones are underexposed. I do shoot ETTR, so I am happy with this photo because I didn't want the ladies shirt in the background to totally blow out and become a white distracting blob. So the next step is a luminosity/contrast curve (duplicate layer using blending mode luminosity).

I changed the number 4 color point to read the subjects face because I wanted to get an accurate luminosity number from the LAB color space. So his face has decreased in all the numbers because everything got lighter. The neutral numbers got lighter but there was no color in them to alter so they stayed neutral. The final photo is -

Color correcting skin tones - with some practice this method of curving a separate color curve to get your colors right - then a luminosity curve to get your tones right should take about 5 minutes. The steps are as follows:

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1. Find a well it section of skin, preferable not the face, to measure skin tones from.
2. Make the persons skin tones a Yellowish Red color/hue
3. Understand what other parts of the photo will be affected by the color correcting curve and make appropriate changes to the photo.
4. Don't force anything that make other objects in the photo have an unnatural color. Work with the photo and the skin tones instead of against them. They have a natural look.

Our next color correcting skin tone colors tutorial takes us to masking in order to achieve a believable color.The Yellowish Red color will be painted onto the skin in order to color correct a persons skin tone in CMYK.

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Camera Composition in Art Photography

I have written a few times in my tutorial blog posts that a photographer should look at good art and photography. The camera is a tool that makes the three dimensional world into a two dimensional photo. Looking at good art is pleasing but the experienced artists have experimented with the use of compositional tools. The tools of line, shape and tone are time honored ways of creating a two dimensional photo.

When ever you look at great photo, the planned compositional elements should become instantly obvious if you know what to look for.The following photograph is an example of line, tone, shape and texture.

The subject matter, shoes, are an age old subject of artistic fascination. Apart from a discussion on the subject of shoes as an art object or whether this photo achieved High Art status, the composition can be separated into certain pieces.

There are three tonal areas which also create a shape. The carpet, the shoes and the yellow fabric on the top. The shoes are obviously the subject because of their placement, tone and contrasting line to the other shapes. The texture of the carpet sets it apart from the shoes as well as the fabric. Both the fabric and the carpet have a pattern associated with it that are similar but also different. The subject is set apart from this pattern with the looping shoe laces and wavy reflection off the patent leather. Some may say that the shoes should not be so centered in the frame. I didn't want to create tension through compositional placement so I kept the subject neutral in the center.

The difference with good to great art and snapshot photos are not so much what TYPE of camera took the photo (that is a totally different discussion) but how the photographer aligned the elements in the frame. Painters sketch out many different compositional ideas in an effort to highlight the subject in order to create an emotional response. Photography is no different. The big difference is the amount of time a photographer might have to capture the subject. Sometimes it is a split second before the conditions change. Other times, like the above photo which was taken during a wedding day and meant for a wedding album, I had only a few minutes before moving on to another subject.

Look at a photography book and start to pick out the three art elements of composition discussed in the tutorial. Then, for kicks, just to see the difference, look at photos on Facebook or a photo posting site and see how many compositional elements are present in those images. If you look at those snapshots long enough, they all look the same and your mind gets numb. They become just another picture that does not inspire any emotional response in the viewer. The subject may be of interest but it is masked, hidden somewhere in all of the uncoordinated compositional elements. Hurry, hurry back to good art photography and never look at amateur photos again (unless they are of your loved ones of course). Learn from the masters who have found artistic love within the camera composition.

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Composition for Photography part 1 - Street Photography

Walking around a city with your camera is fun and potentially a creative endeavor. I see so many people taking photos in New York City and wonder, "what are they photographing that I don't see?". I look and it is another snapshot. I can already pre-visualize what the photo will look like. Composition for photography has many different aspects. One of the more difficult things is to find the composition within the chaos of moving parts. Good street photography is hard because many of your subjects are moving, the composition does not stay static and does not reproduce very easily.

I found that photographing the Horse Carriages on 59th Street in New York City at Central Park were much harder than I first anticipated. putting aside the thought that the composition is always changing so you have to see and act very quickly there are more difficulties.

One such issue is the amount of chaos moving around the subject in the background which can distract from the photograph. While you can find an interesting subject, also looking at and reacting to what the background will look like is another major skill. Being able to match up your background to highlight your subject might be one of the most important skills in street photography.

The other problem I had with this subject was finding a pleasing shape the horses can fit into that makes for a successful composition. I could always zoom in really close and get a horse head, but that is not composing a story telling scene. It is more of horse portraiture. Showing the carriages being pulled by the horses also created compositional problems as seen below. I wanted to show horse and carriages in an active and environmental photo.

The photo above is an interesting subject, the horse and carriage. It is a nice snapshot subject. The horse is cleverly echoed by the statue in the background. I had to crop out all of the distracting people so the viewers eye could focus on the subject. But, in the end I think this photo fails because the horse and carriage are long objects that always point towards the right or left side of the scene, out of the frame. I don't think the lamp post does enough to stop the viewer form leaving the frame. This was the ultimate challenge of creating an interesting horse and carriage photo. What angle should I take that will create a pleasing composition?

The photo below does a much better job. So good in fact that I was not worried about the distracting people and objects to the left or right of the subjects. It starts nicely from the bottom left and moves to the brightest object, the carriage driver with the white shirt. From there your eye can wander over to the other carriage because it is another bright white subject. The other carriage driver brings us back into the scene because he is looking to the left. At this point the viewer can look at the photo in more detail. Ask yourself, hat other aspects of this photo make it an interesting photographic composition.

 

I see people taking photos of buildings all the time. Usually famous buildings. But always from the ground. This creates keystone in a photo. Where the lines start out wide and point upward to a perspective point. In this photo there is plenty of keystone lines but ultimately it works. The reflected building adds curve to a very angular photo. Another layer with interesting shapes and tone that leads the eye to the top of the building with the American flag. The building with the American flag brings us back into the frame and to the trees which point back to the reflection ofn the building. The keystone lines on the building to the left and right become a frame instead of distracting angled lines leading the eye to the top of the frame and out of the photo.

Composition in street photography is no easy task. It is chaotic and most shots turn out to be snapshots of interesting objects with very little emotion or story. If you understand some of the basics of compositional design then you will be more selective in the photos you take and more successful looking for the best angle to take the photos from. The photos above show that by using thought out compositional techniques anything that may be distracting disappears from the viewers mind. People or signs are easily overtaken by the interesting subject and you don't have to over crop or replace items in the photo.

Composition for photography on the streets of a major city does not come easy, but studying it, looking at only GREAT photography and practicing seeing will mold this type of thinking over time. The more you practice and see how other great photographers dealt with difficult photographic compositions the faster you will be able to use it in your day to day street photography. Finding the order in the chaos of street photography.

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Post processing uniwb files

Since uniwb (uni white balance) is a rather interesting topic, I think someone who is going to use it needs to know some advance levels of post processing. More specifically: color correction. Uniwb makes everything green in your photo. Why? Green is the luminance color channel. If you look at the separate RGB channels of a histogram the luminosity channel will be a duplicate of the Green channel.

Another matter to understand is that your camera will be using a linear curve when you shoot in uni white balance. Since uniwb uses RAW files, post processing is easy and nondestructive to the file. But, you have to know how to get from point A to point B with some sort of artistic vision.

I am going to use Nikon Capture NX2 in this tutorial. I like Capture NX and think it does a better job at rendering the colors of Nikon Raw files than Photoshop. Just my opinion. The first photo below is a uniwb raw file right out of my Nikon D700. Linear curve, no sharpening, no added saturation, contrast or D-lighting. Pure binary code from the camera.

Uniwb Raw file out of camera

This photo is rather easy to color correct in post processing. That is why I chose it as an example It has neutral colors (white and black) and greenery to get a basic color reading. With the "set gray point" white balance tool, I chose the front of the middle musicians shirt. It looks like a plain white t-shirt. I chose the front of the shirt because if I choose the top, there might be some green color from the trees reflecting on that area. When choosing white balance, you must be concerned about reflective color from surrounding objects. It can throw off the white balance of the whole image.

Next I like to find a dark, neutral black (if possible) and use the "black control point" tool in conjunction with a watch point measuring that point. I like to find this black point around RGB 8-12. I set the black point on part of the black bag hanging on the fence to the left of the center musician. Set the RGB channels so they all record at RGB 12. That should mean the dark ends of our photo are correct and give some detail in a print or on a computer screen. It also means it is neutral black.

You can do the same to a white point in the photo. Since I used the white t-shirt for the white balance I give it a cursory check and see it is near neutral so there is no need to set a white point. Below is a photo of the color changes after setting white balance and a black point. A slight improvement but still, there is a Green color cast.

Uniwb Raw file with white balance and black point applied

At this point I like to check "known colors" such as foliage, skies, skin tones, things that I think should be neutral. I also like to add a little Nikon Capture NX2 d-lighting. When shooting uniwb with a linear curve, there is no pop, or mid-tone contrast in the photo and the blacks could be blocked up or show no detail. I put the black point in before the d-lighting so the black point can be an anchor and the rest of the darks can be moved to the right so there is the desired amount of detail showing. I call this setting the slope of the darks on the histogram with d-lighting. If you have used d-lighting in Capture NX2 you will know what I am talking about.

Now I check the greenery color ranges in the background. I am a purist and normally check all my colors with the LAB and CMYK color spaces. But Nikon Capture NX2 does not have these color spaces. This makes me have to open the file as a TIFF in Photoshop and check the colors in more detail. For this tutorial I will stay in Capture NX2 and do all my readings in the less accurate RGB color space.

The general color rule in RGB for plants is that the Blue channel should be the lowest number, Green highest, Red closer to Green. In some parts of the photo Red number is higher than the Green value in the plants, so I make a slight change to a curve reducing Red in the color range of the greenery and especially in the area of the curve where the greenery has too much red. Additionally, I want to hold my white and black points to near neutral. So I put a point on the top part of the curve and the bottom part of the curve so they won't move. See photo below.

Make sure all of this is done in color mode so it doesn't affect the luminance (tone) of the photo. In Capture NX2 you want to open the opacity section of the curve at the bottom, choose Luminance and Chrominance. This splits the adjustment into two channels, color and tone. Turn off the luminance and the adjustment will only apply to the color. In Photoshop this is represented as blending modes - color, luminosity. See photo below.

Red Channel Curve

After a change to the Red channel I also see that the flesh tones are way off. There is too much green and yellow in the photo. Separating flesh tones and greenery can be difficult because they usually lay in the same tonal range (between RGB 140-175). The general rule for flesh tones in RGB are Blue should be the lowest number, Red Highest and Green closer to Blue. In this photo I see flesh tones numbers that are RGB 121, 92, 50. The Green is right in between the two other channels and I need it to be closer to Blue.

I can also visually see that there is too much Yellow in the musicians faces so I add some blue in that color range, bringing it closer to the Green Channel number and reducing the yellow, along with a slight bit of Green. I check my greenery numbers in various places making sure I haven't knocked any of them out of the color range rules and, presto. A finished uniwb color correction.

My final color correcting numbers after applying these curves are in RGB values - Black bag hanging 27, 28, 29 - Front of White t-shirt 231, 230, 231 - Greenery point - 79, 87, 48 and forearm of middle musician - 128, 81, 55. These numbers make me happy before I apply any luminosity, contrast or style changes. See photo below.

Uniwb Raw file after color correcting curves applied

Most everything is in a good color range. When color correcting know elements such as neutral colors, greenery, flesh tones, skies, you are looking for those things to be in a range. By doing cursory checks around all of the different tones of the plant life I can make sure the plants stay in the Greenish-Yellow range and not become Reddish-Yellow. Same with flesh tones. There is no exact number, just ranges, and these ranges can be wide. But you want them to be in the Yellowish-Red color spectrum.

As I start to stylize the Raw file, the colors will change, but if you start in a good place then you always have a baseline to create from. Now you can work on luminosity, contrast and personal style. Below is a finalized photo with some luminosity curves, saturation and sharpening applied to make the photo - POP - a little.

Sample finalized photo from uniwb Raw file

When a person decides to use the method of uniwb to bypass the in-camera white balance multipliers, it definitely adds to the digital photography work flow and is not for the light at heart. Uniwb is just a method to help a person get a more accurate exposure. Post processing the files means you really have to know and understand color correction. I hope this post processing tutorial of unwb raw files helped you understand what it means to color correct a photo, some guidelines to follow and how to accomplish it.

You may also want to read the blog tutorial on color correcting skin tones in digital photography.

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Best lightweight Nikon FX lens kit - 28-105mm

My experience in photography, with Nikon cameras and lenses, has brought me to a few conclusions. Pro f/2.8 lenses such as the Nikon 70-200 and 24-70 are heavy pieces of glass. Walking around with either lens for more than 6 hours is tiring. There has been times when a street photo presented itself after 7 hours and my arm was just too tired to raise that Nikon D700 and the 24-70 f/2.8 lens again. Where are the lightweight quality zoom lenses. Even though the new post processing software has image distortion correction I abhor pincushion and barrel types. The new lightweight lenses all seem to think this is an acceptable situation. I was especially disappointed with the New Nikon 24-135 f/4 for this reason alone.

I have owned or used most of the recent Nikon pro lenses and consumer lenses for FX and DX between the focal lengths of 24mm to 300mm. There is a difference of course, and a professional photographer can start to choose the correct lenses for the pre-envisioned job. If I need super sharpness I will use one of the newer lenses. They are very sharp but seems to have what is called nervous bokeh. If I want a more arty shape and tone type photo I will use one of the older lenses.

So my solution for a walk around kit has been to add lightweight lenses. The real trick is to not sacrifice that much in performance as compared to your goals. 

My kit current walk around kit consists a mixture of a Nikon 28-105 f/3.5 to 4.5, a 50mm 1.4G, an 85mm 1.4D and a 180mm 2.8 depending on what I am looking for. Usually 28mm is enough for walking around New York City or any other city but I also have a Sigma 10-20 4.5 to 5.6 DX lens for wide angle real estate photography. It has plenty of nasty distortion but much less than other wide angle lenses in the same price range (at least compared to FX lenses).

Nikon 28-105 f/3.5 to 4.5 - Super lightweight. Great range - from wide to portrait. Very little distortion on either end. Fast focus. Easy 2 to 1 Macro setting. Very nice color reproduction and contrast. Detail is not at the same level as a Nikon 24-70 2.8G but it is very good at the wide end and tapers off in the usual Nikon fashion at the long end. You can only buy this used, so as usual make sure it is a good copy. But that used price is below $300.

Nikon 28-105 f/3.5 to 4.5 28mm f/9

The wide end has very good detail, nice bokeh, very low distortion and not any visually detectable vignetting. This lens was the kit lens with the Nikon F100. The F100 was the semi pro film camera before digital. Something like the D700 is to the D3s today. The long end does very good, with less fine detail but very nice contrast and color which represents shape very well. In a way, I don't want my long end to have excellent detail representation. At 105mm, this is portrait length and having to post process every pore and stray facial hair is not how I want to spend my time. This is a very good portrait lens. And does a fine job in the field too.

Nikon 28-105 @105mm f/10

The dog is running with a little motion blur. There is plenty of detail in the woman's dress as well as through the windows at the Metropolitan Museum of Art. But the Nikon 28-105mm pulls out plenty of detail.

Nikon 28-105 @ 105mm f/5

 Like I said, it is a very nice portrait lens. Plenty of detail, nice bokeh and a pleasing contrast/color rendition.

It is so lightweight and easy to use it has become my favorite walk around lens. Would I use it for professional commercial jobs where fine detail is of the utmost importance. Probably not. For my own personal use, for street photography, for photos that will only be viewed on the web this is a must have lightweight, high quality Nikon lens from days of old.

In the next blog post I will discuss some of the prime lenses I have and currently own as well as some of the other exotic Nikon lenses.

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