The Science of Color
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[ 49 ]in Photoshop. Sounds good, right? A larger color gamut
must mean more color? Nope, that’s the assumption many
people make; but the fact is that, even though this gives us a
greater range of color for processing, about 10–15% of the
colors available in this profile aren’t visible to the human eye.
So why do we use it? Well, compressing colors to a smaller
space such as sRGB can lead to all kinds of issues such as
banding, noise amplification, or worse, limiting your editing
range of color.
THE FUNDAMENTAL RULE OF
COLOR MANAGEMENT FOR OUTPUT
If you want colors to come out the way you expect, you
must, and need, to know two things:
- What is the target output profile? Is it a printer profile?
Is it a web browser profile? What is it? - Am I editing my image for that target output profile?
If you aren’t, then the colors are going to change when
you send your file to that target.
So, where do you find color profiles? How do you change
them? How do they affect your files? This is a lot to digest,
but let’s cover the key areas you should know.
CHECKING THE PROFILE OF YOUR EXISTING FILE
If you’re editing an existing photograph, it’s probably already
an RGB photo. To find out with which profile you’re work-
ing, and change it if you need to, go to Edit>Assign Profile.
When you assign a profile, it converts the existing
embedded color profile used to define your pixel image
data to the new profile. Embedded profiles can come
from your camera, scanner, a website that converts the
images when you upload them, and many other pos-
sible scenarios. Sometimes, though, a file won’t be color-
managed, which isn’t uncommon. It will adopt the color
profile of the environment in which it’s being used. This
is not a good idea, because the colors will shift constantly
from media to media with no consistency at all. If you
check the Preview box in the Assign Profile dialog, and
then select various profile options in the drop-down
menu, you’ll be able to see how different color profiles
influence the colors in your image.
Here’s an example where you can see that there’s varia-
tion in the colors between each image. The left image is
how the image was originally captured. I shot this photo-
graph in Glacier National Park with a Nikon D850 set to the
Adobe RGB color profile. The image in the middle has been
assigned the sRGB profile, and the last image is what it
looks like when we assign ProPhoto RGB. Note the dramatic
differences, especially in the blue colors of the sky.Nikon D850 set to the Adobe RGB color profile sRGB color profile ProPhoto RGB color profile