Joe's How-To

A Practical Guide to Color Space

Joe Doherty August 2021 Focal Points Magazine

You’ve probably come across the terms sRGB, Adobe RGB, and ProPhoto RGB. One or more of these are listed as options in your camera menus and editing software. They influence what you see on your monitor, how your images appear on the web, and how you print your photographs. But what are they, and what are the practical implications of choosing one over another?

sRGB, Adobe RGB, and ProPhoto RGB are color spaces. They define the shades of Red, Green, and Blue (RGB) that can be output by your camera, that can be displayed on your device, and that can be printed. If you are familiar with The Zone System, popularized by Ansel Adams, you’re familiar with the idea of a scale that progresses from pure black to pure white, with eight or more shades of gray in between. Color spaces are similar. Each color (R, G, or B) has a value. If all values are zero (0,0,0), then the “color” is black. If all of the values are at their maximum (255,255,255 for sRGB), then the “color” is white. Combinations of these values produce the shades we can see and use.

Those shades are the “gamut” of a color space. There are two ways to think about gamut. The first is to think of each color space as a triangle anchored at the corners by values of red, green, and blue. Some color spaces are simply bigger. They can render deeper shades of those colors than others. The second way to think about gamut is in terms of subtlety. A color space whose color values range from 0 to 255 is capable of much greater subtlety than a color space whose values range from 0 to 9. A shade that can be displayed in a color space is considered “in-gamut,” and shades that cannot be displayed are “out-of-gamut.”

The color spaces sRGB, Adobe RGB, and ProPhoto RGB each have a progressively larget gamut. sRGB has 16.8 million shades of color. Adobe RGB has about 1 billion. ProPhoto has . . . I don’t know how many shades it has, but that isn’t a problem. ProPhoto is the color space that Lightroom assigns to your raw file when you import it from your camera. But there is a hitch. There are no monitors capable of displaying the ProPhoto gamut. The type of monitors used by photographers display sRGB or Adobe RGB, so for practical purposes ProPhoto doesn’t matter.

What are the practical implications of using sRGB or Adobe RGB? It depends on what you want to do with your images. I’m going to assume that you are familiar with raw files from your camera. Raw files have no color space, and they have no white balance, so the software you use will ultimately determine the color space.

If your goal is to share your images on the web and upload images to make prints (at Costco or Shutterfly, for example), then sRGB is probably fine. Web browsers can only display sRGB, and many processes for making prints (traditional wet prints, prints on aluminum, custom greeting cards, etc.) utilize the sRGB color space. Most computer moni-

tors display only in sRGB (some better than others, so do some research), which means that you can see any edits you make as they will appear in those media.

Keep in mind that since you started with raw files converted to ProPhoto, there are still colors in your file that you cannot see on your monitor. These may affect how the image will look elsewhere, so the next step is crucial. Export your images in the sRGB colorspace. In Lightroom it’s an export option. In Photoshop you can use the Edit>Convert to Profile menu option, or the File>Export menu option. This will strip away the other colors. From that point forward, what you see is what you get.

When would you want to use Adobe RGB? It is for when you want to make highquality prints using a process that’s capable of a broader range of colors. Adobe RGB was created to enable computers to send images to production printers that use CMYK inks, like modern inkjet printers. Those printers have a much broader range of possible colors than sRGB. Does it make a difference? In certain circumstances it makes a very big difference.

Velda and I make a trip every fall to photograph the aspens, dogwoods, and cottonwoods as they change color. From experience I’ve learned that there are shades of orange and yellow in the trees that result in amazing prints, but that are impossible to reproduce in sRGB. The colors on my website are not as subtle or as saturated as the colors that hang on the wall. I would like to be able to show you side-by-side examples of these, but that would be futile because Focal Points is produced using the sRGB color space. Instead I will show you an example of “out of gamut” colors using a photograph from October 2020. These are from Photoshop. On the left is a screen capture of aspens at North Lake. On the right is the same image, but the colors that cannot be accurately reproduced in sRGB are grayed-out.

Those grayed-out areas will still be printed, as the software will approximate colors, but they will not be the actual colors. These approximations are almost always muted and muddy. The transition of color within the leaves is lost, along with the texture and detail.

Setting yourself up to edit images in the Adobe RGB color space requires a monitor that can display those colors. I use a Dell Ultrasharp, and Ben Q is also a good brand. Check the specifications before buying, as both manufacturers also make sRGB-only monitors. To get the most out of your monitor you’ll need to calibrate it, which is something I’ll talk about in a future column.

There is a lot that goes into making a file that is ready to print (also the subject of a future column) but here are the main points for this column. Export the file in the Adobe RGB color space and save it as a TIF, not a jpg. Then find a professional printer who can make a fine art print on an inkjet printer. Alternatively you could join Los Angeles Center of Photography, take Eric Joseph’s printing class, and use the printers they make available to members. As a last resort, and only if you have room for a small piano in your house, you could buy your own a high-end printer.

Understanding the difference between sRGB and Adobe RGB can help you to produce better images, and help to explain some otherwise confusing results. Thinking about the ultimate use of the photograph, and having a planned workflow to get you there, can save time and provide consistent results. And knowing what using the wrong color space can do to your photographs, and having the ability to spot and fix it, can turn discouragement into celebration.

Malibu. I think I decided these were elegant terns. I’m not sure if you heard that in Bolsa Chica, about 2500 elegant terns abandoned their eggs when a drone crashed in the middle of the nesting area. I think there’s a $5000 reward for information about who’s drone that was. ©Paul Reinstein, all rights reserved

MORE OUTINGS NEWS

As the Sierra Club National Outings and the Angeles Chapter Outings Management Committee (OMC), explore options for rolling out an outings agenda as the Covid-19 pandemic (hopefully) begins to wind-down, the Camera Committee’s leaders met twice in April to discuss preparations and consider proposals.

Primary in our conversations is refreshing our leadership skills and recertifying our first aid certificates. We are confident that when OMC is ready to sanction activities, our leaders will be refreshed and recertified and ready to hit the trail.

Outings are likely to re-emerge in tiers with the simplest local hikes coming first and the more complex multi-day adventures coming on line later. Members should expect to see changes in outings requirements and styles. There will always be the liability waiver to sign. In the early outings, there will be the now-familiar mask and social distancing requirements though standard wills evolve on the advice of the CDC and other medical professionals. Whether vaccination will be required is yet to be determined. The Sierra Club’s goal is to present the most equitable opportunities with the least risk, please stay tuned.

Also, please consider launching your personal outings preparation. Trip teasers Here are some Camera Committee outings that might come to pass, if not in 2021, well…let’s hope for 2022. From the simplest to more complex:

• Griffith Park: Sunset Hike to view the Observatory and DTLA awash in golden light. (Joan Schipper) • Orange County: Fall Bird Migration (Allan Der) • San Gabriel Valley/Mountains: Arroyo Seco Day Hike with possible fall colors. JPL to Brown Mountain. (Allan Der) • Mojave Desert: Mojave Trails National Monument Exploration (Wesley Peck) • Eastern Sierra Nevada Mountains: Fall Colors Exploration • Owens Valley: Mono Basin exploration, Wild Mustang in Adobe Valley, Hot Springs (Allan Der) • Owens Valley: Dunderberg Meadow Wildflowers in Spring, fall colors in Autumn (near Lee Vining) (Wesley Peck) • Mesquite, Nevada: Little Finland in Gold Butte National Monument (Carole Scurlock) • Southern Arizona: Organ Pipe Cactus National Monument (Alison Boyle) • Northern Arizona: Toroweap Overlook on North Rim, Grand Canyon National Park (Allan Der) • Outer Space: There is also talk about night sky meteor shower observation and photography.

We are all hoping that in the next Focal Points, we will be able to offer outings with dates and locations. For now, our leaders have to hit the maps and the road and get scouting. We look forward to seeing you all on the trails or on the road.

Joan Schipper and Alison Boyle – Outings Co-Chairs

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