Join Joe Brady for an in-depth discussion in this video Comparing types of color spaces, part of Advanced Color Workflows for Photographers.
Comparing different color spaces is an interesting exercise that may help you better understand the differences in each. Now in addition, there are two basic types of color spaces, device dependent and device independent. Let's start by taking a quick look at the common color spaces and compare them to one another. Color spaces are actually three-dimensional constructs, so viewing them in two dimensions is very limiting. So, here we are in Apple's color sync utility that allows us to view and compare these spaces. Let's start with ProPhoto RGB.
So, here we see this big plot of ProPhoto RGB. And it's lovely, but by itself, it doesn't really tell us anything. We need to compare it against something else. So let's, for example, hold this one. We've gotta hold it for comparison. And we're going to dump Adobe RGB into it. And you see it right here on the list. And now, we can see, as we spin around, that white, ghosted area is ProPhoto RGB space, and inside that is Adobe RGB. Let's also take a look at sRGB, and we can see it's even smaller as we scroll around here.
So on the bottom, by the way, you see the black to the white up on the top. So it's showing the tonal range. And then the distribution of the colors through the entire space. Now, we see that the relative sizes of each color space seem to insinuate that, well, we should always be using ProPhoto RGB. And in many times, that's going to be the case, at least when you're dealing with raw files, especially if you're dealing with 16-bit. If you're dealing with 8-bit TIFFs or JPGs, then there's a problem using Pro Photo RGB because it actually becomes too big.
Now let's see why. Remembering how big ProPhoto RGB is, if you're dealing with an 8-bit file, that means you'll only have 256 steps from dark to light for each color channel. So, imagine those 256 steps spread across the vast space of ProPhoto RGB. If you try to edit this 8-bit file, you're moving and deleting data. And what happens is you end up leaving bigger spaces between each gradation and that can lead to artifacts and banding in your images. Now, 16-bit files compared to 8-bit have over 65,000 steps for each channel, 65,536 to be exact.
That means you have a lot of room for editing before those gaps start to become a problem. The short answer here is that if you're going to live in the ProPhoto RGB world, and I recommend you do, then you need to stay with 16-bit files until you're ready to export them for someone else to print them or to put them on the web. So we've seen what device dependent spaces are. How about these device independent spaces? What do you need to know about them? Device dependent spaces are linked to the physical characteristics and abilities of a specific device to reproduce or describe color.
When working in ProPhoto RGB in Photoshop and displaying on an Adobe RGB-capable monitor, the software uses the monitor's profile to best translate the ProPhoto color information into the capabilities of the monitor. Device independent color spaces describe color in a way that more closely mimics the capabilities of the human eye or at least a standardized measurement of what the human eye can perceive. The advantage of having such a space is the ability to describe a color and translate it from one device dependent space, your monitor for example, to another device dependent space like your printer.
Your image editing softwares are actually doing this all the time behind the scenes. There is one device independent space, however, that has a lot of uses for Photoshop users, and that's the L*a*b space. While you can technically do pretty much Edit-Done in the L*a*b space in RGB, there are some operations that do have unique results. The ability to adjust luminance without affecting colors or conversely, the ability to boost colors without affecting luminance are two common operations that those fond of this space like to use.
Here's a screen shot, showing where you can find the L*a*b space option in Photoshop under Image > Mode > Lab Color. The real power and usefulness of the L*a*b space is that it both emulates color akin to how the eye perceives it, and it also contains all of the possible human perceived colors. Even ProPhoto RGB only covers about 90% of human vision. The L*a*b space acts as the universal translator to help color move from one device to another with a minimum loss of color and tonality, thereby causing as little data loss as possible.
There are a lot of operations in Photoshop that you can do in this space, and there are some hefty books and courses that cover this in detail, perhaps a subject for another day.
In this course, Joe Brady builds on his Color Management Fundamentals course, focusing on color-management issues of specific interest to photographers. After a review of digital-color concepts, the course explores creating color profiles for each device in the digital photography workflow, from monitor to printer, to camera. Joe demonstrates the tools and techniques behind color profiling, even covering tablets—ideal for photographers using iPads or Android tablets as wireless remote controls.
- What gear can and should be profiled?
- Comparing color spaces
- Choosing a monitor
- Profiling your monitor
- Paper-profiling devices
- Profiling iOS and Android devices
- Soft proofing