Alain Briot tip of the month

Eredeti: Alain Briot July 2010 newsletter

Tip of the Month
Digital Photography changes quickly and significantly. Keeping up with these changes is important. You have to update your hardware and software, and you have to learn how to use all the new features. Failure to do so means you will soon find yourself behind the curve, wondering what happened and unable to create images that competes with the work of other photographers.

However, it is also important to know how much updating is enough. You do not need to update your software and hardware daily, weekly or even monthly. Keeping up with changes and improvements is important, but so is going out and creating new photographs, something that can be done even if you do not have the latest, and supposedly best, camera or equipment.

In the end it is important to keep in mind what our goal is. Our goal is to create fine art photographs. As such, our goal is to first and foremost express ourselves. Our goal is to express our emotions and share with our audience not only what we saw but also, and more importantly, what we felt when we create photographs in the field.

Sharing our emotional response to the scenes we photograph is not related to having the latest camera, software or equipment. It is related to being passionate about the subjects we photograph. It is related to the inspiration we feel when we photograph. And it is related to knowing what we want to share with our audience and how we want to share it: our personal style, our vision in a word.

In doing so, the equipment, the camera and the software we use are tools. They are facilitators. They make doing what we do possible, and as time goes by they enable us to do this better and better by giving us more and more control. However, without inspiration and passion, these tools will only allow us to do a good technical job. Tools alone will not communicate emotions and passion. For that, we need to go out there and let go for a minute of the constant upgrading process that we can so easily fall prey to.

The RAW File Format

Eredeti:Cambridgeincolour, ismeretlen szerző

The RAW file format is digital photography's equivalent of a negative in film photography: it contains untouched, "raw" pixel information straight from the digital camera's sensor. The RAW file format has yet to undergo demosaicing, and so it contains just one red, green, or blue value at each pixel location. Digital cameras normally "develop" this RAW file by converting it into a full color JPEG or TIFF image file, and then store the converted file in your memory card. Digital cameras have to make several interpretive decisions when they develop a RAW file, and so the RAW file format offers you more control over how the final JPEG or TIFF image is generated. This section aims to illustrate the technical advantages of RAW files, and makes suggestions about when to use the RAW file format.

A RAW file is developed into a final JPEG or TIFF image in several steps, each of which may contain several irreversible image adjustments. One key advantage of RAW is that it allows the photographer to postpone applying these adjustments-- giving more flexibility to the photographer to later apply these themselves, in a way which best suits each image. The following diagram illustrates the sequence of adjustments:

	Demosaicing White Balance	Tone Curves Contrast Color Saturation Sharpening	Conversion to 8-bit JPEG Compression

Demosaicing and white balance involve interpreting and converting the bayer array into an image with all three colors at each pixel, and occur in the same step. The bayer array is what makes the first image appear more pixelated than the other two, and gives the image a greenish tint.

Our eyes perceive differences in lightness logarithmically, and so when light intensity quadruples we only perceive this as a doubling in the amount of light. A digital camera, on the other hand, records differences in lightness linearly-- twice the light intensity produces twice the response in the camera sensor. This is why the first and second images above look so much darker than the third. In order for the numbers recorded within a digital camera to be shown as we perceive them, tone curves need to be applied.

Color saturation and contrast may also be adjusted, depending on the setting within your camera. The image is then sharpened to offset the softening caused by demosaicing, which is visible in the second image.

The high bit depth RAW image is then converted into 8-bits per channel, and compressed into a JPEG based on the compression setting within your camera. Up until this step, RAW image information most likely resided within the digital camera's memory buffer.

There are several advantages to performing any of the above RAW conversion steps afterwards on a personal computer, as opposed to within a digital camera. The next sections describe how using RAW files can enhance these RAW conversion steps.

Demosaicing is a very processor-intensive step, and so the best demosaicing algorithms require more processing power than is practical within today's digital cameras. Most digital cameras therefore take quality-compromising shortcuts to convert a RAW file into a TIFF or JPEG in a reasonable amount of time. Performing the demosaicing step on a personal computer allows for the best algorithms since a PC has many times more processing power than a typical digital camera. Better algorithms can squeeze a little more out of your camera sensor by producing more resolution, less noise, better small-scale color accuracy and reduced moiré. Note the resolution advantage shown below:

JPEG (in-camera)
RAW
Ideal

Images from actual camera tests with a Canon EOS 20D using an ISO 12233 resolution test chart.
Differential between RAW and JPEG resolution may vary with camera model and conversion software.

The in-camera JPEG image is not able to resolve lines as closely spaced as those in the RAW image. Even so, a RAW file cannot achieve the ideal lines shown, because the process of demosaicing always introduces some softening to the image. Only sensors which capture all three colors at each pixel location could achieve the ideal image shown at the bottom (such as Foveon-type sensors).

White balance is the process of removing unrealistic color casts, so that objects which appear white in person are rendered white in your photo. Color casts within JPEG images can often be removed in post-processing, but at the cost of bit depth and color gamut. This is because the white balance has effectively been set twice: once in RAW conversion and then again in post-processing. RAW files give you the ability to set the white balance of a photo *after* the picture has been taken-- without unnecessarily destroying bits.

Digital cameras actually record each color channel with more precision than the 8-bits (256 levels) per channel used for JPEG images (see "Understanding Bit Depth"). Most current cameras capture each color with 12-bits of precision (2¹² = 4096 levels) per color channel, providing several times more levels than could be achieved by using an in-camera JPEG. Higher bit depth decreases the susceptibility to posterization, and increases your flexibility when choosing a color space and in post-processing.

The RAW file format usually provides considerably more "dynamic range" than a JPEG file, depending on how the camera creates its JPEG. Dynamic range refers to the range of light to dark which can be captured by a camera before becoming completely white or black, respectively. Since the raw color data has not been converted into logarithmic values using curves (see overview section above), the exposure of a RAW file can be adjusted slightly-- after the photo has been taken. Exposure compensation can correct for metering errors, or can help bring out lost shadow or highlight detail. The following example was taken directly into the setting sun, and shows the same RAW file with -1 stop, 0 (no change), and +1 stop exposure compensation. Move your mouse over each to see how exposure compensation affects the image:

Apply Exposure Compensation:	-1.0	none	+1.0

Note: +1 or -1 stop refers to a doubling or halving of the light used for an exposure, respectively.

A stop can also be listed in terms of eV, and so +1 stop is equivalent to +1 eV.

Note the broad range of shadow and highlight detail across the three images. Similar results could not be achieved by merely brightening or darkening a JPEG file-- both in dynamic range and in the smoothness of tones. A graduated neutral density filter (see tutorial on camera lens filters) could then be used to better utilize this broad dynamic range.

Since a RAW file is untouched, sharpening has not been applied within the camera. Much like demosaicing, better sharpening algorithms are often far more processor intensive. Sharpening performed on a personal computer can thus create fewer halo artifacts for an equivalent amount of sharpening (see "Sharpening Using an Unsharp Mask" for examples of sharpening artifacts).

Since sharpness depends on the intended viewing distance of your image, the RAW file format also provides more control over what type and how much sharpening is applied (given your purpose). Sharpening is usually the last post-processing step since it cannot be undone, so having a pre-sharpened JPEG is not optimal.

The RAW file format uses a lossless compression, and so it does not suffer from thecompression artifacts visible with "lossy" JPEG compression. RAW files contain more information and achieve better compression than TIFF, but without the compression artifacts of JPEG.

Compression:	Lossless	Lossy

Image shown at 200%. Lossy JPEG compression at 60% in Adobe Photoshop.

Note: Kodak and Nikon employ a slightly lossy RAW compression algorithm, although any artifacts are much lower than would be perceived with a similar JPEG image. The efficiency of RAW compression also varies with digital camera manufacturer.

• RAW files are much larger than similar JPEG files, and so fewer photos can fit within the same memory card.
• RAW files are more time consuming since they may require manually applying each conversion step.
• RAW files often take longer to be written to a memory card since they are larger, therefore most digital cameras may not achieve the same frame rate as with JPEG.
• RAW files cannot be given to others immediately since they require specific software to load them, therefore it may be necessary to first convert them into JPEG.
• RAW files require a more powerful computer with more temporary memory (RAM).

One problem with the RAW file format is that it is not very standardized. Each camera has their own proprietary RAW file format, and so one program may not be able to read all formats. Fortunately, Adobe has announced a digital negative (DNG) specification which aims to standardize the RAW file format. In addition, any camera which has the ability to save RAW files should come with its own software to read them.

Good RAW conversion software can perform batch processes and often automates all conversion steps except those which you choose to modify. This can mitigate or even eliminate the ease of use advantage of JPEG files.

Many newer cameras can save both RAW and JPEG images simultaneously. This provides you with an immediate final image, but retains the RAW "negative" just in case more flexibility is desired later.

So which is better: RAW or JPEG? There is no single answer, as this depends on the type of photography you are doing. In most cases, RAW files will provide the best solution due to their technical advantages and the decreasing cost of large memory cards. RAW files give the photographer far more control, but with this comes the trade-off of speed, storage space and ease of use. The RAW trade-off is sometimes not worth it for sports and press photographers, although landscape and most fine art photographers often choose RAW in order to maximize the image quality potential of their digital camera.

Alain Briot: Composing with Colors - 3. rész

Eredeti: Alain Briot, Composing with Color - Part 3

by Alain Briot

This essay is part of Chapter 5 in Alain’s second book
Mastering Composition, Inspiration and Personal Style

7 - Saturation

To see in color is a delight for the eye
but to see in black and white is a delight for the soul.

Andri Cauldwell

Saturation is both an important and an overused aspect of color. In short, it is just too easy to over saturate a photograph, either globally or locally, in order to make it more colorful or more interesting.

Certainly, it can be said that over-using the two other variables of color is just as bad. Making a photograph too light or too dark is not good either. And having too many different hues in an image is a sure recipe to make it look gaudy. Similarly, reducing the hues to a minimum may remove interest in the image altogether.

None of these are good, and all of them are symptoms of image maladies, a concept we will explore in depth in the chapter of the same name later in this book. But right now I want to address saturation specifically, because I believe that this subject needs a little discourse now followed by a few remedies later.

The problem with saturation starts with raw files. Raw files are by nature desaturated. This is simply one of the aspects of capturing photographs in raw format. Therefore, in order to make them look “normal,” whatever this might mean to each of us, we have to increase their saturation level. This is often the source of problems with color photographs.

There is nothing easier than over saturating an image. Why? Simply because I think that saturation is addictive. More is better, or so it seems. Since I started teaching digital photography, which goes back to 1995, I have seen very few photographs that lacked saturation. However I have seen countless photographs that were over saturated. Some were slightly over saturated and many were greatly over saturated. In just about all instances, the photographers, the artists, were not aware that their images were oversaturated.

Over saturation is easy. Just drag the slider to the right and there you are: instant interest. And certainly, the majority of the public likes saturated color images. In fact, if you want to quickly create a popular image, simply over saturate the colors and increase the contrast. While you may not achieve a sophisticated image, you will achieve an image that will please a less demanding audience.

It’s a little like cooking. If you can’t achieve a dish that has enough flavors, add salt. If that doesn’t work, add pepper. Salt and pepper are to unrefined cooks what over saturation and high contrast is to unrefined photographers. They work, but they do so superficially. Furthermore, go one step too far and the dish is inedible or the photograph gives you a headache when you look at it. The line is easily crossed and most do cross it. Finally, twenty years of overly salty and peppery food, or of overly saturated and contrasty images, will cause you to lose your appreciation for properly seasoned cuisine and properly processed fine art images. There is a risk. I mention it here so that if you decide to take this route you know what you are getting into.

So how do you prevent over saturation? Simple. The first thing is being aware of the risk, something we took care of in the previous paragraph. The second thing is acquiring a taste for how much saturation is enough. This is best achieved by comparing your work to photographs that you consider to be properly saturated. These are photographs that you like, that you admire, and that you want to use as models for your own work.

You can do this by comparing your images on screen to images found on the Internet. Or, you can do this by comparing your prints to reproductions in books or magazines. However, the very best approach is to compare your fine art prints to original fine art prints of the images you want to use as models. Why? Because everything else besides an original print is, well, a reproduction. And reproductions are not as good as original prints. Something is missing and the quality is lower than that of an original. That is why they are reproductions, and that is why reproductions cost less than originals.

The photographs below show the same image subjected to a range of saturation increases and decreases. In this example I chose to divide saturation in 5 categories: normal, lower than normal, total desaturation, higher than normal and maximum saturation. It is possible to create finer differences between each category, and you may want to do so. Here I wanted to keep things simple for the purpose of this example so I limited myself to 5 categories.

These examples are provided as a study guide. You may want to create your own examples using your own photographs. Finally, keep in mind as you look at these images below that the only change made to the photograph is saturation increase or decrease. No other modifications were made.

Global Color Saturation Levels Example

No saturation / Lower than normal saturation / Normal saturation

Above normal saturation / Maximum saturation

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Global and Local Saturation

The next thing to do in learning to not over saturate your photographs is learning to differentiate between global saturation and local saturation. Global saturation is saturation increase or decrease applied to the entire image, to all the colors in the photograph. Local saturation is saturation increase or decrease applied to part of the image, to some of the colors in the photograph.

Usually, when converting a raw file you will start by increasing global saturation, working on the saturation of all the colors in the image. You need to do this while being careful to not over saturate colors. As I mentioned, you can use another photograph as a guide to determine if you are going too far or not.

As you study the results of this saturation increase you may notice that one or several colors have increased in saturation more than the other colors. In other words, you may find that one or several colors are oversaturated. If this is the case you will need to do a local desaturation by working only on some of the colors in the image.

Local over saturation often occurs with distant objects or features in the landscape. Things that are far away in a landscape are by nature less saturated than things that are close to us. This is because atmospheric haze, as well as dusk, vapor or other particulates in the air, reduce saturation. This means that the further an element is from us, the less saturated it will be.

If, in a photograph, a far away element is more saturated than a nearby element, the photograph will not be believable to the viewer. That may be fine if such is the intent, but if it is unintentional it will cause the viewer to lose interest in the image. Of course, viewers will not come to you and say “I really enjoyed looking at your photograph until I realized that the mountains on the horizon were more saturated than the flowers in the foreground at which time I lost interest in the image because I found it to no longer be credible while your attempt is clearly to create believable representations of the landscape.” This will never happen, or hardly ever I should say (never say never, there’s always someone to prove you wrong when you do!). It won’t happen because you are supposed to know all of that. You are expected to have control over your medium and you are expected to be aware of the effect you intend to create with your work.

The solution to local over-saturation is to lower the saturation of the afflicted color. Usually, blue is the color that over saturates the most in landscape photography. To cure the problem, simply lower the saturation of the blues and the problem will go away. We will see how to cure this malady in greater detail when we get to the Image Maladies chapter.

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8 - Color Seeing Aides

In my photography, color and composition are inseparable. I see in color.

William Albert Allard

Zone VI Filter

Zone VI filter / Zone VI filter in use

There are a number of tools that can specifically help you see and compose with color. In this section we are going to take a look at these tools, in no particular order.

The first tool is a color-viewing filter that was made by Zone VI. Zone VI is no longer in business. It was bought by Calumet Photo who may still offer this viewing filter (I have not checked if they do). Zone VI also made a black and white viewing filter that I describe in the next chapter: Composing in Black and White.

The goal of a color-viewing filter is to show the contrast and color balance of a specific film. I am not sure which film the Zone VI filter was designed to emulate but it does increase the contrast of the scene and it does make it look bluer. Maybe it was designed to emulate Ektachrome since this film had a color balance shifted towards blue.

I have always had mixed feelings about color viewing filters. We see in color, so why use a color-viewing filter? After all, it will show us the world in color, something we could see without the filter! The contrast increase and color shift are helpful to a point but the filter also makes things darker, which makes composing more difficult than without the filter. I never used this filter much, certainly far less than the black and white viewing filter.

In film days the goal of a color filter was to duplicate the contrast and color of a specific film. With digital capture, color viewing filters have become far less useful since contrast and color can be adjusted at will. Since the filter can only show one contrast and color combination, one is better off looking at the LCD screen on the digital camera.

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LCD Screen

With digital capture using your LCD screen to visualize the color in your photographs is much more effective than using a color viewing filter. Color viewing filters were all we had prior to digital. Today they are passé to say the least.

There are a few things to keep in mind though when you use your LCD screen as a visualization tool.

First, colors on the LCD screen are based on the color balance setting you selected on your camera. Changing this setting will change the color balance of the photographs displayed on the LCD screen.

Second, this color balance can be changed in the raw converter later on with no penalty or loss of quality (see color balance above and in the Image Maladies and Remedies chapter). Therefore, the choice of color balance in-camera is not final.

Third, the image on the LCD screen is generated from a jpeg that is itself generated from the raw file. The conversion settings used to create this jpeg are based on the settings on your camera. This means that the quality of the image on the LCD screen may not reflect the full potential of the raw file.

Fourth, your LCD screen can only exhibit some of the colors in the raw file. This of course is dependent on the quality of your LCD screen, but the quality of the LCD screen is not as good as a calibrated, large gamut monitor for example and definitely not as good as a Fine Art Print.

Fifth, if exposed correctly the image on the LCD screen will appear too bright. This is due to an approach called exposing to the right, which calls for overexposing digital captures to record more bits of data. Inversely, in instances where you wish to preserve extremely bright highlights, the image on the LCD screen may appear too dark. In either case, images that are overly bright or dark make for poor color evaluation. In these instances, which are common with digital capture, I recommend that you take a photograph for the sole purpose of viewing it on the LCD screen. When the capture was exposed to the right this viewing image will have to be underexposed, and when the capture was exposed to preserve highlights it will have to be underexposed.

Sixth, keep in mind the goal is not to do “LCD art.” This means that the image on the LCD screen is only an evaluation image and not the final artwork. Don’t go too far in making it look good! You’ll waste valuable time better spent capturing other photographs while the light is great. Instead, do only what is absolutely necessary to have an LCD image that you can evaluate properly, then use what you learned from looking at the LCD screen to refine your composition.

Nigrometer / Nigrometer in use

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Nigrometer

Another useful tool used to study color is a Nigrometer. This tool is very simple in design. It consists of a tube with a 1/4 inch hole at each end. You use it by looking at a specific area of color through the tube.

No light reaches inside the tube, making the inside black. When you look at a specific area through the Nigrometer, the color of that area is isolated from other surrounding colors. This allows you to study a single area of color, something that we cannot normally do because we cannot narrow our sight to the size of the opening in the Nigrometer. As a result, through our eyes alone we see several areas of color at once and we cannot isolate a single area of color.

A good exercise to conduct with the Nigrometer is to look at the same object under different light conditions. For example, if you look at a patch of grass in direct sunlight and in the shade, you will see the grass take on two very different colors. The grass will be a low saturation light yellow-green when it is in the sunlight and a high saturation darker green when it is in the shade.

Doing this exercise with a variety of subjects and lighting conditions will teach you a lot about color and light.

I am not sure if you can buy a ready-made Nigrometer. I have always made mine from simple supplies. All you need is a narrow poster tube with a plastic cover at each end. Make a hole with a paper punch in both plastic covers, and paint the caps as well as the inside and outside of the tube with black spray paint (the black color is necessary to neutralize colors). Finally, glue or staple the caps to each end and you are ready to go.

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Munsell Color Tree

GretagMcBeth Munsell Color Tree

The Munsell Color Tree is a 3D model of the Munsell Color System. I previously discussed it at length in the section on the Munsell Color System, so I only want to mention it briefly here. This device is sold by GretagMcBeth and I bought mine from their website. A slightly different version is available from Munsellstore.com.

Priced around $300 this is not a cheap tool. However, I find it to be extremely valuable to study how the Munsell Color System works, and to study how hue, saturation and lightness work together in changing specific colors. I use it when I want to visualize how a specific color will look if I make it darker, lighter, or more or less saturated. I also use it to determine the color palette of a specific image.

One of the nicest aspects of this tool is that the color patches are actual prints and not reproductions. In fact, each patch is glued by hand to the sheets of Plexiglas. This means that short of printing these patches yourself on your own printer, these colors are as close as they can be to the actual color. As I mentioned before, the only original is a fine art print and everything else is a reproduction. These patches are originals, not reproductions, and this most likely accounts for the cost of this tool.

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Color Meters

Minolta IIIF color meter / Gossen Sixticolor color meter

A color meter is an instrument that measures the color of the light. Because light color is measured in Kelvin degrees, which I described previously, a color meter gives measurements in Kelvin degrees.

Above are two types of color meters. At left we have a Minolta IIIF and at right a Gossen Sixticolor. The Minolta is one of the most sophisticated color meters, not only giving the temperature of a light source but also indicating which filtration is necessary to correct this light source for a specific film type.

The Gossen Sixticolor is a much simpler type of color meter that also gives the temperature of a specific light source. The Sixticolor uses a galvanometer instead of a battery and is much less costly than the Minolta IIIF. Both of these meters are no longer produced but can be found on eBay or in used camera stores or websites.

Today, with digital capture being the norm, we no longer need to filter the light to color balance a specific film type. However, knowing the temperature of the light is still useful when making an assessment about the quality of the light and when considering which color the image will be.

However, this is also something that we can find out by looking at the image on the LCD screen. Changing the color balance setting on your camera will change the color of the photograph. By playing with the color balance settings, and by comparing how the color of the photograph changes with different settings, you can estimate the temperature and the color of a specific light source.

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Grey Cards and WhiBal

Small WhiBal / Large WhiBal

Balancing color is a challenging endeavor, as we saw earlier and as we will see again later on in the chapter titled Image Maladies and Remedies. However, there are a number of tools designed to help you. Above is one of them, called WhiBal, which is designed and produced by my friend Michael Tapes.

The predecessor of the WhiBal was the Kodak grey card that was designed to be used with film. The Kodak grey card was middle grey and to use it you took a photograph with the card in it prior to taking the actual photographs. By using the same lighting conditions on the grey card and in the actual photographs, you could use the grey card to color balance the prints.

The same approach is used with the WhiBal except that WhiBal includes black and white surfaces in addition to the middle grey surface. On top of that, the middle grey surface is optimized for digital (don’t ask me how this is done, ask Michael) making it ideal for color balancing digital captures.

You use the WhiBal just like you would use a grey card, by taking a photograph with the WhiBal in it followed by the actual photographs, all under the same lighting conditions. Later, in the raw converter, you use the color balance eyedropper and click on the grey WhiBal to set the color balance. If you also want to use the WhiBal to set the black and white points, you can use the black and white eyedroppers in Photoshop to click on the WhiBal black and white patches.

This will let you set the color balance for the photograph, and alternatively the black and white points. Personally, I set the white balance in the raw converter and I adjust the black and white points in Photoshop using separate curve adjustment layers for the black and for the white points.

What you need to keep in mind is that while setting a neutral point is very important, when doing creative photography it is not always necessary to have a pure neutral grey point in the image. For example, if you photograph at sunset or sunrise, the sunlight has a warm color that you should keep in the final image. This means that color balancing the image to a pure neutral grey will not work since doing so would remove the warm glow of sunrise or sunset.

Similarly, you may want to add a colorcast to a photograph on purpose, for example to express a particular feeling or emotion. A snow scene with a bluish color balance will look colder than with a neutral color balance. Similarly, a slightly magenta color balance will make the image look warmer than a neutral color balance. Other situations may call for different color shifts, based on your personal ideas, goals, inspiration and personal style.

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McBeth Color Chart

Front MacBeth Color Chart - Back / MacBeth Color Chart - Patch Values

Another way to study color is to use a McBeth color chart. This chart was designed to be photographed or scanned, either by itself or by including it in a photograph, very much like you would use a grey chart or a WhiBal.

Photographing a MacBeth color chart gives you more information about the color of the light than photographing a grey card alone. This is because the color chart gives you16 color patches and 3 shades of grey in addition to black, white and middle grey. Photographing these color patches lets you see how different colors react to different light temperatures.

On the back of the chart you have the names of each color, and on the accompanying values chart you have the RGB values for these colors.

This chart is very useful to test how colors change with exposure. How to conduct a test showing how color changes with over and under exposure is described in the exercises section of this chapter.

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About This Essay

This essay is part 3 out of 4 of Chapter 5 in Alain’s second book Mastering Composition, Inspiration and Personal Style. Part 1 and Part 2are available on this site. The book is available now. You can order at this link: http://beautiful-landscape.com/Articles-Book-2-1.html

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About Alain Briot

Alain Briot creates fine art photographs, teaches workshops and offers DVD tutorials on composition, printing and on marketing photographs. Alain is also the author of Mastering Landscape Photography. This book is available from Amazon and other bookstores as well as directly from Alain. You can find more information about Alain's work, writings and tutorials as well as subscribe to Alain’s Free Monthly Newsletter on his website at http://www.beautiful-landscape.com. You receive 30 free essays in PDF Format when you subscribe.

Alain welcomes your comments on this essay as well as on his other essays available. You can reach Alain directly by emailing him atalain@beautiful-landscape.com.

Alain Briot
Vistancia, Arizona
July 2010

Alain Briot: Composing with Colors - 2. rész

Eredeti: Alain Briot, Composing with colors

Composing with Color
Part 2

by
Alain Briot

This essay is part 2 of Chapter 5 in Alain’s second book
Mastering Composition, Inspiration and Personal Style

4 - Controlling Color in Photoshop

It is not the form that dictates the color, but the color that brings out the form.
Hans Hofman

The model described by Munsell is also present in digital photography in a second way, besides color spaces. It is present in Photoshop in the Hue/Saturation adjustment dialog box. The Hue Saturation dialog box gives you access to the three variables of color independently: Hue, Saturation and Lightness, just as Munsell described them in 1921:

These three adjustments work exactly the way I previously described them: hue controls color, saturation controls how intense that color is, and lightness controls how light or dark the color is. These controls duplicate Munsell’s description of color precisely.

In practice, when using this dialog box, I change primarily the saturation level, occasionally the lightness level, and rarely the hue setting. This approach is personal and is based on my personal preferences regarding image adjustments. As to how I control each variable of color in Photoshop, since I do not control all 3 three variables through Hue/Saturation, this is something that we will see in the chapter titled Image Maladies and Remedies.

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5 - Color Balance

The difficulty with color is to go beyond the fact that it is color – to have it be not just a colorful picture but really be a picture about something.
It's difficult. So often color gets caught up in color, and it becomes merely decorative.
Some photographers use it brilliantly to make visual statements combining color and content; otherwise it is empty.
Mary Ellen Mark

One of the most important aspects of color photography is color balance. Color balancing a photograph means adjusting the overall color of the image so that neutral colors are rendered correctly. Color balance is sometimes called grey balance or white balance.

From a technical perspective the goal of color balancing is getting a neutral color to be truly neutral, that is without a colorcast. From an artistic perspective, the goal of color balancing is to get colors to be pleasing to the eye. Either approach is correct. I personally use a combination of both, working towards getting neutral colors to be truly neutral and working towards creating a color balance that is pleasing to me.

Color balance can be set in your digital camera by selecting one of the options in the color balance menu (auto, shade, daylight, flash, etc.). This will change the appearance of the image on the LCD screen. However, when you capture the photograph in raw format, the color balance information is only “tagged” to the image data and can be changed later on during raw conversion. In other words, the color balance setting used on your camera does not alter the raw file in any way.

I personally set my camera to Auto white balance most of the time, then adjust the white balance to the settings of my choice during raw conversion. It is important to set the proper white balance at the time you convert the image. The reason for this is because a raw file is a single-channel file and as such adjusting the color balance is much easier and much more accurate than adjusting the color after the image has been converted. After conversion, the image becomes a tri-color image –Red, Green and Blue—and color correction must be done on three channels instead of one. Furthermore, a raw file is not a photograph but instead a set of numbers and data that will be transformed into a photograph by the raw converter. As such, any modifications made at that stage are applied not to a photograph but to raw data. You are affecting the way the photograph is created, a much more reliable approach than modifying the photograph itself after conversion.

Both digital cameras and raw converters offer a variety of color balance settings. On the next page you can see the different color balance settings offered by Adobe Lightroom 2.0. These different settings were all applied to the same photograph. No other changes were made to this photograph besides changing the color balance. The color balance settings used are indicated under each version of the photograph.

Color balance is adjusted by changing two values: the color temperature (“temp” in the screenshots below) and the tint (tint in the screenshots below). The color temperature allows you to adjust the image from blue to yellow, while the tint allows you to adjust the image from green to magenta. Green and Magenta are opposite (adding green removes magenta and vice versa) and so are blue and yellow (adding blue removes yellow and vice versa).

The tint value indicates how much or how little magenta or green is added or removed. The temperature value indicates a value in Kelvin degrees. Kelvin degrees are used to measure the temperature of a light source. Cold light (blue) has a high Kelvin number while warm light (yellow-orange) has a low Kelvin value. For example, tungsten light, which is warm, has a value around 2800 Kelvin degrees while overcast northern light, which is cold, can have a value has high as 10,000 Kelvin degrees.

These values are used in the screenshots below. Each preset indicates the Kelvin degree value for the type of light source that was selected. For example, the daylight preset indicates a temperature of 5500, the Kelvin temperature of sunlight at noon, while the tungsten preset indicates a temperature of 2850, the average light temperature of tungsten light bulbs.

The tint is also adjusted by the preset. The proper color balance is achieved by adjusting both temperature and tint.

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6 - Color Palette

I've been forty years discovering that the queen of all colors is black.
Henri Matisse

Color palette is another very important concept to take into account when working with color.

Color palette is different from color balance. As we just saw, color balance is about balancing the color of the light so that neutral tones are truly neutral or so that colors are pleasing overall. Color palette, on the other hand, is about selecting a range of colors that are going to be used in the photograph.

Color palette is a painting term. In painting, you start with a blank canvas. Therefore, defining the color palette lets you choose the colors that will be placed on the canvas. We can think of painting, for the sake of argument and learning, as an additive process. When painting colors are added to the blank canvas.

In photography, you start with a frame filled with elements and colors. Therefore, defining the color palette is often a matter of modifying or, in some instances, removing colors from the photograph. We can think of photography, also for the sake of argument and learning, as a subtractive process. When photographing we subtract, or remove colors and elements from the original scene.

Considering the color palette part of the act of creating a fine art photograph is a novel concept. It demands that you give yourself the freedom of altering, modifying, enhancing or manipulating your photographs, as you prefer to put it. This is an important step that you have to take as an artist in order to develop a personal style (remember that we are talking about art here, not about forensic, scientific or other literal photographic representations). Nobody forces you to “manipulate” your work. However, it is necessary that you take a stand for or against manipulation. This is an important step. The chapter titled Just say yes, in this book, is here to help you with this aspect of developing a personal style. So are the four chapters devoted to the creative process, chapters that are specifically designed to help you work towards the achievement of a personal style.

For now we are considering color palette for what it does best and that is the selection of a range of colors that will be used in a specific photograph. Color palettes are defined for a single photograph, or for an entire project if you are working on a project and wish this project to have a continuum in regards to color (a color continuum we might say). You could, for example, work on a project in which the color palette makes use of a variety of blues and whites. Or, you might work on a project in which warm hues are used, such as reds and browns.

When defining a color palette all three variables of color are used: hue, saturation and lightness. For example, when defining the warm palette I just mentioned, you might decide to use saturated light reds and low saturation dark browns. Just by writing this short description we have precisely defined the two main colors of your palette. These two colors, as we just described them, would look like this for example:

In the image above I circled in red the colors that I defined in the previous paragraph.

Two important things need to be said about what I just did. First, I used the Munsell Color System, and more specifically the photograph of the 10 color panes from the Munsell Color Tree that we discussed previously.

Second, I circled not a single color, but a group of colors. And, I did that for the two colors that I previously defined.

Why did I do this? I used the Munsell Color System because I want to tie the concept of color palette with what we studied previously in regards to color, and that is the Munsell Color System. It makes sense to do this since we are talking about color in the terms that Munsell introduced: hue, saturation and lightness.

Using the Munsell Color System to define a color palette has another important advantage. Because Munsell’s description of color is used in Photoshop and other image processing software, there is a direct relationship between Munsell and digital image processing. In other words, if we define a color with the Munsell Color System we can create this color very easily in Photoshop by using Hue/Saturation, or some of the other tools that we will study later on in this book.

Why did I circle more than one color? After all I talked about single colors, not groups of color therefore I should have circled a single color. I did so because when talking about a color palette we are not referring to a single color. Instead, we are referring to a group of colors. In other words, there is room to “err” for lack of a better term. The expression “color palette” is not a scientific term. Instead, it is an artistic expression that is used to indicate a range of colors rather than a single, specific color.

What is great about the Munsell Color System is that it works both as a scientific approach and definition of color, as well as an artistic approach and practice of color. It can do both because this system can be used in a very specific manner or it can be used in a more general manner. Using the Munsell Color System within a specific color space, one can define a color using RGB values. Using the Munsell Color System in a more general manner, as we do in this section on color palettes, one can define a color in general terms of hue, saturation and brightness.

When defining a color palette for artistic purposes, as we are doing here, saying that we want high saturation light reds and low saturation dark browns is all we need. Circling the range that these two colors encompass on the Munsell Color Charts is specific enough for our purposes.

Why? Simply because a photograph, even when its color palette is restricted to two colors, will have a certain variation of tones within these two colors. In other words, the photograph will have more than two colors in reality. A photograph composed of leaves, for example, which are desaturated dark brown in the fall, photographed in front of a sandstone canyon wall, which could be light saturated red if in full sunlight, will have many variations of reds and many shades of brown. Yet, its color palette would be light saturated reds and dark desaturated browns.

In other words, the color palette is defined in simpler terms than the actual colors used in the artwork, be it a photograph or a painting. This is the beauty and the power of a color palette. Because it is somewhat vague and unspecific, it gives to the artist the to interpret the color palette according to their own style and inspiration. In practice, it gives them the freedom to invent the actual colors. The outcome is that two different artists working with the same color palette would most likely not create the exact same colors. This is the beauty of art: the lack of specific values results in endless variations in the creations of each individual artist.

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Defining a color palette using Chromix Color think

There is another way to define a color palette besides using the Munsell Color Tree. This other way is using Chromix ColorThink to map the colors of the photograph into a color space. This mapping can be done by itself, or it can be superimposed onto a specific color space to see how much of this color space is used by the photograph.

Indian Paintbrush Photograph
color space side view and Top down view

This is exactly what I did with the photograph titled Indian Paintbrush. I opened the photograph in Chromix ColorThink and graphed its colors in 3D. The result is the graph seen above next to the photograph.

The image inspector dialog box from which you create a 3D graph of the photograph

Chromix ColorThink is a color analysis software that can map the colors of a photograph into a color space, in this case a LAB color space. The resulting graph is comparable to the graph of any color space, such as those we saw previously in this chapter.

The graph at left above shows the colors that are present in the photograph looking at the color space from the side. The graph at left above shows the same color space looking from the top down. Each color in the photograph is represented by a small dot of color on the graph.

When looking at the colors from the side we see the Lightness axis running vertically at the center of the graph and we see the Color axis going in four different directions towards the corners of the graph. We learn a number of things from looking at this graph. First, there are only a few colors in this photograph. Second, the color that is dominant in quantity and in saturation is red, as shown by the large amount of space taken by the red dots. These dots extend very far to the right, meaning that the reds are very saturated. Remember that the visual representation of the colors in this photograph follows Munsell’s System. Saturation goes from the center outward, Lightness goes up and down and Hues go in a circular way around the color space.

Third, we can see that there are no extreme bright or dark areas in the image and that therefore the contrast of this photograph will be low. This is shown by the dots in the center of the graph, along the vertical Lightness axis. These dots do not go all the way to the top or the bottom of the color space, showing that there is little or no pure white and pure black in the image.

The top down view shows the same information but provides a better view of the colors found in this photograph. It confirms what we saw previously: reds dominate and are the most saturated color while the rest of the colors consist essentially of soft mauves, greens and blue-greens. None of these colors is very saturated, as shown by the dots being close to the center axis.

Photograph and sRGB color spaces side view Top down view ColorThink Logo

The two graphs above show the same information but now I added the graph of the sRGB color space on top of the photograph color space. I chose the sRGB color space for this example, however any color space can be used. The color space is in full color, while the photograph is graphed as it was in the previous graphs, with dots of color. The photograph is now located within the sRGB color space and is seen by looking through the sRGB color space which is shown as semi-transparent for the purpose of this illustration.

The first thing we notice is that the colors in the photograph occupy only a small area of the sRGB color space. While there are a lot of nuances of color in the photograph, there are not that many different colors, meaning the color palette used in this photograph is small. If we circle the colors found in this photograph on the Munsell Color Tree panes, we have this representation:

The colors found in Indian Paintbrush circled on the Munsell Color Tree panes

We also see that the colors do not exceed the color space boundaries. In fact, even the reds, which are the most saturated colors in this photograph, are well within the boundaries of the sRGB color space. This is good news since it means none of the colors are clipped, therefore giving us detail in every area of the image.

Seeing the color space also confirms that the brightness range is small since none of the colors reach the top, or the bottom, of the sRGB color space.

All this information is very useful in helping us define the color palette used in this photograph. This is a more technical approach than finding the colors on the Munsell Color Tree but it works just as well. My recommendation is that you use both approaches since, as we just saw, they complement each other very well.

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About this Essay

This essay is part 2 / 4 of Chapter 5 in Alain’s second book: Mastering Composition, Inspiration and Personal Style. Part 1 is also available on this site.

Alain’s new book is available now. You can order it directly from Alain, signed and with a Companion or Master Print, at this link.

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About Alain Briot

Alain Briot creates fine art photographs, teaches workshops and offers DVD tutorials on composition, printing and on marketing photographs. Alain is also the author of Mastering Landscape Photography. This book is available from Amazon and other bookstores as well as directly from Alain. You can find more information about Alain's work, writings and tutorials as well as subscribe to Alain’s Free Monthly Newsletter on his website.

Alain welcomes your comments on this essay as well as on his other essays available. You can reach Alain directly by emailing him atalain@beautiful-landscape.com.