The Digital Photo Experience

We received the following question for our DPE podcast, but after asking Eddie “The King of Color Management” Tapp to answer it, we thought we’d address it here.

One of Eddie’s colorful photographs leads off this column.

Here is the Q – followed by the A.

Q: As I understand it, there are the key color spaces for photographers: sRGB; Adobe RGB & ProPhoto RGB, the former being the most limited in its color gamut and the latter the most robust.

Now, because most computer monitors (apart from the high-end $1,500 and above models) cannot display anything beyond the sRBG gamut, and most if not all home printers cannot print the colors beyond the sRGB gamut, why would anyone work in any colorspace other than sRGB on his/her photo editing software?

Would appreciate some enlightenment on the subject.

Thanks.
Sam Wiedermann
Jerusalem, Israel

A: Sam’s concerns are certainly valid, and for what I call a “closed loop workflow,” where you only have one camera, one workstation, one editing application and one output device where the color spaces are limited, sRGB will certainly serve a purpose. Also, sRGB is the only color space you should use for Internet images. Outside of that, the color gamut is much larger.

There are actually four standard working color space. Colormatch RGB wasn’t mentioned and is valid for prepress workflow.

Sam is certainly correct about most monitors, their color gamut and dynamic range is similar to the color gamut of sRGB. The fact is, that most printers today (even home printers) color gamut is approaching and even surpassing Adobe RGB, and that’s just the beginning, as the technology continues to improve.

Here’s something we all need to know. Your image processing will be in either 8 bit or 16 bit mode. Your digital cameras sensors are going to capture images that are in 12 or 14 bit resolution. sRGB, Adobe RGB and ColorMatchRGB are 8 bit color spaces, yet Adobe RGB will yield a larger color gamut taking more advantage of the 8 bit 256 brightness levels and 16.7 million colors.

ProPhoto RGB is a 16 bit color space taking advantage of 4.5 billion brightness levels along with trillions of colors. ProPhoto RGB is the only color space that will take full advantage of the 12 or 14 bit sensor in your digital cameras but only if you are shooting RAW. If you’re shooting only JPEG, setting the camera to Adobe RGB will yield a larger color gamut within the 8 bit mode.

ProPhoto RGB is for 16bit images and holds the largest amount of color and tonal data possible for a controlled color managed workflow. Processing your images initially in 16bit and ProPhoto RGB ensures the highest possible photographic tonal range encompassing a large color space, smooth transitions between shadow, mid-tone and highlight regions. From there, converting to sRBG 8 bit for labs or the Internet takes on the best possible use of sRGB’s color space and in most cases will yield minimal clipping or visual color differences.

Adobe Lightroom’s default color space is ProPhotoRGB, meaning that from your RAW or DNG file workflow, you are automatically accessing the best possible processing capabilities. In Adobe Photoshop you have to setup Adobe Camera Raw to process your images in 16Bit ProPhoto RGB.

In short, even if all you need is sRGB, processing your initial work in ProPhoto RGB (16 bit) and then converting to sRGB (8 bit) will give you the best possible quality that sRGB could possibly yield.

For my work, preparing for the best possible tonal range and color gamut is important for the work I do today and for the technology that’s coming tomorrow.

Respectfully,
Eddie Tapp
M.Photog., MEI,Cr., API

P.S. Rick back here to say “thank you” to Eddie for taking the time to answer this question. You rock, dude. I’ve learned a lot from your seminars, CD, workshops and articles! You have helped me make accurate color prints from my photographs, like this shot of a Huli Wigman whom I photographed in Papua New Guinea.

And don’t forget to join Eddie Tapp, Judy Host and Randy Hufford in an amazing Maui Photo Adventure! Email Eddie for a full day-by-day description at email hidden; JavaScript is required or visit http://ivamaui.com/tapphost for more information.