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Color Spaces Simplified

with 2 comments

By Gary Small

 

This map compares how much of the color spectrum (that large oval in the far back) different color spaces cover. ProPhoto RGB covers the most of the spectrum, Adobe RGB is the second largest, and sRGB is the smallest. Also shown is the color limits of the Epson 2200 printer (printing on Matte paper). Image by Jeff Schewe.

Greetings. Here’s a question I hear quite often. What color space should I choose when shooting? The answers I’ve heard have been so varied that it can oftentimes leave you more confused than when you first asked! I will try and simplify it here for you and hopefully it will reduce some of the confusion.

First of all, what is a color space? Well, to put it simply, think of a color space as a container, holding all the colors that were used to display or print a particular image. Some color spaces use more colors, some use less.

Put another way, think of when we were kids and we played with those boxes of crayons. Some of us had the box with only 8 colors. Some had 32 and some had the big box with 64 colors and the built-in sharpener. But you may have noticed that even if you had that big box of crayons, not only didn’t you use all of the colors in the box, but typically you found yourself using many of the same few colors over and over again. That’s the idea behind choosing and using a color space. We try to choose one that contains the colors we will use most often.

The human eye is capable of seeing the most colors. Presently, no mechanical device has been able to reproduce all of the colors our eyes are capable of seeing. So any color space you use will always contain fewer colors than our eyes can see; so we have no trouble there. The place we get into trouble is in reproducing colors across various media. For example, some colors we can view on a monitor cannot be reproduced by an inkjet printer and somehow that has to be dealt with.

Without getting overly technical, the most commonly used color spaces are, sRGB, Adobe RGB (1998), and ProPhoto RGB. The difference between all of these is the number of colors each one uses.

sRGB is the narrowest of all the color spaces and was developed for the web, with the idea of being a universal color space. In other words, any images that would be displayed on a web page would be rendered in this color space. It uses the fewest colors, which keeps images smaller and more efficient.

On the other end of the scale, ProPhoto RGB is the widest color space and uses the most colors out of all of them. It is typically thought by many pros that this is the color space to work in; because you wouldn’t have to worry that a color or color range you want to work with won’t be available to you.

Somewhere in the middle is Adobe RGB (1998). This was considered a good balance between the extremely narrow sRGB and the very wide and robust ProPhoto RGB.

Most digital cameras nowadays will give you a choice of choosing either Adobe RGB (1998) or sRGB. I am not going to tell you absolutely which color space you should choose because everybody works differently. I hope to be able to help you make an informed decision on your own, once you’ve read this article.

To help you, you must first and foremost, think about what will be done with the finished images you are producing. Since most output devices reproduce fewer colors than are contained in the wider color spaces, any images produced in a wider color space will have to be converted before being sent to that device. The simplest idea to think about is, if you are shooting images that will only be going onto a web page and will never be printed, sRGB would be the color space to work in, since that’s the color space used on the web. If you are printing on an inkjet printer, believe it or not, it too has a narrow color space that very closely resembles sRGB. So you’d probably do well with it there, too. If you are going to output onto more complex imaging devices which work with larger amounts of colors, you might consider working in a wider color space like Adobe (1998).

More things to consider:

When you work in one color space and need to output to a device that works in a different color space, a translation must occur. Let’s say you are working (or shooting) in Adobe (1998) and printing onto an inkjet printer that works in sRGB. You’re going from a wider to a narrower color space. What that means to you is, there are more possible colors in the image you shot with your camera than the printer can possibly reproduce. So when translating the colors for the printer (think of a funnel), the colors that aren’t reproducible on the printer have to be converted into different colors that that printer can reproduce. They will be translated into colors that will try to simulate the original colors as closely as possible, but will not always match. So there’s always a chance you will lose some of the original colors your image had when you captured it. This is when you hear terms like “clipping” and “out of gamut”. This refers to dealing with colors outside the range of that device and how to handle them. But again, I don’t want to get overly technical here.

My best advice is, keep it simple. Try to work as closely to the color space that you will be outputting to. If you don’t know where you’re outputting or may be outputting to various places, you may want to choose a wider color space. Although there are many who feel that you should just work in the widest color space possible and go from there, I feel that is not always the best choice or the most efficient. But that’s just my opinion. When photographing social events, like weddings, I usually shoot on sRGB, because the images are going onto the web for the family and guests to view, as well as being printed on printers that work within that color space. When I shoot commercial images, I tend to work in a wider color space, like Adobe (1998), because the clientele tends to be more critical and the subtlety of the colors may be more important.

Of course, I always encourage people to experiment and see what results work best for you. But I believe this should give you a good place to start. Hope this helps. Happy shooting!

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2 Responses

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  1. “Let’s say you are working (or shooting) in Adobe (1998) and printing onto an inkjet printer that works in sRGB.”

    Except that most inkjet printers today have gamuts that are significantly larger than the sRGB color space. more and more reasonably price displays have gamuts that exceed sRGB as well.

    “Try to work as closely to the color space that you will be outputting to.”

    This is the “dumbdown theory of color management.” Which is not the same thing and in fact is antithetical to the Keep It Simple Stupid method of working.

    In the Jeff Schewe image you use an illustration by Jeff Schewe that is misleading in some key aspects.

    – Primarily it is out of date. The Epson 2200 is obsolete by at least three if not more generations out of date. Since then there have been changes in both print head and ink technologies that have surpassed the limited range of color (gamut or palette) the 220o was capable of ,even o nthe consumer level.

    – Even more importantly, the paper type — matte paper — always has a more limited range of color than a semi-gloss or gloss paper is capable of.

    So you are taking an out of date, worst case example to use to illustrate your point. Words mean something but pictures have meaning too.

    “if you are shooting images that will only be going onto a web page and will never be printed, sRGB would be the color space to work in, since that’s the color space used on the web.:”

    I use sRGB as a color space for photos that are only going to be reproduced o nthe web for the reason that the most widely used internet browser , Microsoft’s Internet Explorer is deliberately dumbed down to sRGB. While all color spaces are artificial constructs , sRGb was created wit hone purpose only: to be able to use color in graphics like pie charts on a very bad condition CRT (picture tube technology from the late 1980s 1990’s) in the worst possible viewing conditions (lots of bright light and glare. It was never intended to be used for photographic purposes. That Microsoft still insists to this day on limiting Internet Explorer to sRGB says much about how they see people using the web.

    But recommending sRGB as a default color space for photography? That’s like having your shoe laces tied together as soon as you enter the ring.

    Ellis Vener

    December 3, 2009 at 9:24 am

  2. Ellis,
    As the editor, it was my choice to use the Jeff Schewe image. Having the Epson 2200/matte paper combo is out of date. Thanks for pointing out that we should be using a more up to date image.
    Diane

    PictureSoup

    December 3, 2009 at 12:25 pm


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