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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Easy UniWB tutorial for Nikon D700, D3, D300

This tutorial will show you the real steps to installing uniwb on your Nikon D700, D3, D300 What is Uni White Balance or uniwb for short? It is a way for the photographer to bypass the in-camera processing multiplier applied to the White Balance. Why would a photographer want to do this? In order to get the most accurate tonal reading during the capture photography phase.

UNIWB is only for RAW file shooters. When a photographer loos at the image on the built in camera screen or looks at the channels histogram they are looking at a JPG interpretation of the RAW data. The cameras processor multiplies the captured data of the red, green and blue channel by a certain number depending on which camera you use. As a RAW data shooter, we want to see the actual data, uninterpreted by the cameras internal programming. Using UniWB gives you this ability. It bypasses the computer interpretation of white balance (which is usually wrong) so you can set the best ETTR (exposse to the right) capture.

For a more technical elaboration on UNIWB you should  do a search search for Iliah Borg or uniwb. This tutorial is not about why to use UNIWB but how to load it on a Nikon D700.

I have loaded UNIWB on my D200 and D70. The Nikon D700 adds an extra step because you have to put the data onto a CF card via a card reader.

To download the Nikon  D3/D700 uniwb files goto...http://dl.dropbox.com/u/17057675/ND700UniWB.zip ... and unzip the folder.

To download the Nikon D300 uniwb files goto ... http://stats.sergiodelatorre.com/dlcount.php?id=_GUI_&url=http://www.guillermoluijk.com/download/uniwbd300.nef and unzip the folder

Step 1. Format your CF card in the Nikon D700
Step 2 take a photo
Step 3 goto shooting menu on your Nikon D700 and then manage picture control
Step 4 goto save edit -->> choose any picture control -->> hit ok -->> then save it with a name
Step 5 goto manage picture control again -->> load/save -->> copy to card and choose the picture control you just made to be put onto your CF card.

Now you have 2 folders on your CF card.... one Named Nikon and one where the photos are stored.

Step 6 Take the DSC_0001.NEF file (this is the UNIWB file) from the zip folder and rename it with the name of the photo you took after formatting your card. Now replace the photo file on your camera with the renamed UNIWB file.

Step 7 The other part of using UNIWB is to have a flat curve in your picture control file.The corresponding ncp file in the download is this flat curve. Take the piccon01.ncp file, in the NIKON folder from the zip file and replace the file in the Nikon folder on your CF card with it. Before doing this I would name it linear or something you will remember as associated with the uni white balance. - now put the CF card back into the camera.

Step 8 goto shooting menu on the camera -->> White Balance -->> preset manual -->> select a slot to put the white balance photo onto and click the pad -->> select image -->> and the camera will automatically go to the photo on your camera -->> then set with another click of the controller pad.

Step 9 goto shooting menu -->> manage picture control -->> load/save -->> copy to camera -->>and choose the picture control you put onto your CF card.

To use the UNIWB you need to choose the PRE White Balance assigned to the UNIWB setting and use the picture control Linear (which is what I named my UNIWB flat curve picture control).

*** if this tutorial helped you, please click on an add. It helps me eat so I can keep on writing helpful information***

Now you will have green photos but an accurate histogram portrayal of the data your camera captures. This is the main reason for using uniwb, accurate luminosity in all three color channels. But, I must also warn the photographer that uses uniwb; that you must shoot RAW and be an experienced post processor.

Post processing uniwb takes decision making. You have to decide what the true white balance of the photo actually is during post processing. Furthermore, since you are using a linear curve, you will have to make decisions about contrast, saturation, tone curves. Essentially, the camera does nothing but capture the binary 1,s and 0's of the digital language. Truly, unwb is all about being a lover of photography. It is an easy process but it adds another step to the process of making a pretty photo.

My next blog digital photography tutorial is about color correcting uniwb files.

Or learn about color correcting skin tones in this tutorial.

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Photo viewing on a computer monitor

Digital photography has changed almost everything about a photograph. Not only are photographers able to process a photo on a computer but they are able to instantly view the image on the camera monitor. Photography is everywhere if you have a some sort of digital device. Without making any judgments about whether this is a good thing or not, some understanding of viewing photographs on a digital device is essential to a modern day photography.

The most important problem for photographers is something called the viewing environment. When a photographer displays a print, they have determined what that print is going to look like and it is a hard copy which will not change. When you view a photo on a computer the interpretation of that image is device dependent. The photographer has no control over how the image is viewed.

There is an international calibration standard called an ICC profile. Unfortunately most devices do not follow this standard in any way. When you go to buy a computer monitor all of the settings on that monitor are meant to dazzle with brightness, contrast and over saturation. Most monitors out of the box are set too bright, not just computer monitors but hand held devices and even the camera monitor you proof the photo on.

A monitor is like putting on a different pair of glasses. Your eyes see the world normally but if you put on glasses with a blue tint then everything turns a little blue. It is a filter. The computer monitor is the same way. They have settings. If it is set too blue then all of the photographs you look at will have a blue color cast. Your eyes adjust to this color cast with something called chromatic adaptation. If you go and print that photo (which observes ICC standards to interpret the information) the colors and tones will all look different from the monitor interpretation. What is a photographer to do?

One person looks at your portfolio and their monitor is set too bright so all of your highlights have no detail. The contrast is off, the colors are flat and the black point looks like a quarter tone. The file tells the computer to do one thing but the monitor settings do another thing.

Here are a few tests to see how well your monitor interprets tone.

Your monitor should see all of the tones on the above chart evenly. This is not very hard for most monitors because there are huge tonal jumps between the squares. If you don't see a difference between all of the squares (especially the 0-13 and 242 to 255) then your monitor is way off ICC standards.

The chart below shows one, two and three tone differences starting at RGB 245. The first square on the top left is a one tone difference between RGB 245 and 246. The next square on the right is a two tone difference and the last is a three tone difference. My monitor shows the difference between RGB 245 and 246 but by the RGB 248 to 249 box there is no perceptible change in tone. My monitor barely shows a difference on the bottom right square of RGB 248 to 251. This is the highlight portion of your monitor.

To further test the sensitivity of your monitors tonal interpretation visit this excellent graphic at Dry Creek.

The same types of test need to be evident on the monitors black point. The link below is excellent at determining your monitor black point settings. My monitor starts to see a tonal change at RGB 6. Monitor Black point/Shadow test

The viewing environment for photography should be very important to a photographer. Someone who works in graphics must learn how to calibrate monitors or at least understand when a device is showing the wrong information. They cannot control how other people view the photographs and new hand held devices compound this problem, but the original file should be correct. That is all we can really control.

Professional photographers have to understand the points in this photography tutorial. It leads directly to proper post processing techniques. When post processing an image for media devices a good standard is:

1. black point to at least RGB 8 
2. white point to RGB 248.

If you have a printer then you need to test it for the points where it stops showing detail in the black and white areas. My current printer shows no detail before RGB 12 and after RGB 242. All printers are different depending on quality. They will have different white and black points. They follow ICC standards, so a print is more reliable to judge what a digital photograph actually represents, but the printer may also have improper mechanics or even settings. Less likely than having a bad monitor but you should be aware of the possibility. That is why we proof our images with the printers ICC profile in Photoshop.

All digital monitors and printers interpret the information of a digital photography file. If the mechanics or settings are wrong for that device then the glasses (interpretation) need to be changed so it can see at 20/20 vision again, or international ICC standards.

We want our photos to be all they can be. I really dislike looking at photographs on a digital monitor. I just like the direct connection to the art a printed photo gives me. It feels more like real photography. It is a tactile experience that interacts with your whole body.

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Photography exposure tutorial for beginners - shutter and aperture

Photography is about painting with light onto a recording mechanism. Exposure is a simple camera technique which can be difficult for beginners to initially grasp.

At one time light was captured by a camera and exposed onto chemicals. Today we have electronic sensors which filter the light and let a powerful computer translate the information into binary code. We have changed what records the light but the system of controlling the exposure is the same as it was since the beginning. A photographer manages the amount of light by controlling the lens aperture, the camera shutter speed and the sensitivity of the recording material. A simple technique for beginner and professional photographers!!!

When I began photography, remembering the F-stop aperture intervals was the hardest and most frustrating thing. Mostly because the numbering is opposite to logical thinking unless you know what the number means. Logically thinking, a larger number would mean MORE of something. So if I wanted to increase the amount of light I made the aperture number larger (ex F/16 compared to the smaller number of F/5). Well that was wrong of course because the aperture designation is a fractional number.

An F-stop is a calculation between how wide the aperture blades will open (diameter) compared to the focal length of the lens. So if the focal length is 8 times the diameter of the diaphragm or blades opening, then the F-stop is F/8. A smaller number means the aperture blades are blocking less of the lens opening. The aperture blades on the chart below are represented by the inside circle while the lens diameter is represented by the outside circle. A larger aperture equals a larger circle.

F/2.8 has a wider opening and as such, allows in more light. Many times you will hear a photographer call a lens a "Fast Lens" which is a designation applied to lenses that have a maximum f-stop of F/2.8 or wider. See what I mean. Maximum would be considered in logical terms as a higher number (ie. maximum speed, maximum height, etc) but in photography terms it means the maximum the aperture can open. Photographers want wide, maximum openings in their lenses. You really don't have to know the math of calculating aperture. Just why that number is what it is and how it affects a photograph.

The first thing a photographer wants to remember are the aperture f-stop numbers. Start off with the full stops, which allow in twice the amount of light when opening and limit one half of the light when closing.
F-Stops in full stops -

1.4 -- 2 -- 2.8 -- 4 -- 5.6 -- 8 -- 11 -- 16 -- 22
<-------more light------------less light-------->

Going from f/4 to f/2.8 allows in twice the amount of light.

Going from f/5.6 to f/8 lets in half the amount of light.

Shutter speed is the same way. A larger number allows less light to hit the film plane. The shutter opens for 1/60th of a second or 1/500th of a second. The next thing (but not as important for reasons I will explain later) is to memorize the full stops of the shutter speed. This is also easier because all you are doing is doubling the number.

1/30 -- 1/60 -- 1/125 -- 1/250 -- 1/500 -- 1/1000 -- 1/2000 of a sec.
<---------more light---------------------------------less light---------->

Going from 1/250th of a sec. to 1/125th of a sec. lets in twice as much light.

Going from 1/60th of a sec. to 1/125th of a sec. lets in half the amount of light.

And finally there is ISO which is also easy to remember because just like shutter speed, you double the number for each full stop. But unlike f-stops and shutter speeds, this number is logical. Increase the number and you double the amount of light that the film/sensor will capture. Depending on your camera the number will start at a different figure. My Nikon D200 had a base ISO of 100 while my D700 has a base ISO of 200. I am going to use a base ISO of 200 for my numbering.

200 -- 400 -- 800 -- 1600 -- 3200 -- 6400 ISO -----> more light

ISO is how sensitive the sensor/film is to light. By increasing the ISO you are increasing the amount of light the camera can capture. Increasing by one stop lets the sensor read twice as much light and decreasing by one full stop lets the sensor read half the amount of light.

A photographer has to figure out what is the best exposure for a particular scene. In the old days you used and memorized an EV chart. These days it has become much easier to get a correct exposure (or in the ball park) due to technology. Cameras have built in meters that give a representation of the exposure via a histogram or plus/minus bar.

Below are three photos where I effected my exposure via one of the three main ways. Either increasing ISO, having a wide aperture or a mixture of aperture and shutter speed to get a correct exposure in a back lit situation.

Over time and with experience, you will know the ballpark exposure setting for a particular lighting situation. After that you will fine tune the exposure via the histogram and for artistic taste. The first thing a beginner photographer needs to do is understand and hopefully memorize these camera settings. I stated them in full stop settings but most cameras will let you move between 1/3 stops for more control over the light. Recording light on a digital camera sensor is no different than the days of film. Digital photography has made it easier to get instant access to what the photograph will look like with a certain aperture, shutter speed and ISO setting combination. So as a beginner you should experiment as much as possible and over time you will master your camera exposure settings.


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