Using color management is a critical element of getting your digital photos from capture through print. If you want your prints to look their best you should establish and follow a color-managed workflow.
Color management refers to a system of computer hardware and software working together to translate color from one device to another in a controlled way.
A digital image file contains a defined range of colors, described mathematically. In Photoshop, this is referred to as the fileâ€™s Working Space. The most common working spaces are sRGB, Adobe RGB (1998) and ProPhoto (I prefer the latter).
Different devices (monitors, printers etc.) will interpret the color numbers in a file in different ways, because of the differences in the nature of the device and their primaries (their main colors – red, green, blue or cyan, magenta, yellow, black etc.) No device can reproduce all colors and all devices reproduce color differently. The range of colors that a device can reproduce, or that a file can contain, is called the Color Gamut. Since an image file also has a limited number of possible colors too, a file can be considered to have its own gamut.
Color management is used to control the consistency of how colors appear to your eye when going from one device to another. This is done through a Color Management System, or CMS. The CMS on Mac is called ColorSync, which handles color management automatically in the background. However, different programs, such as Photoshop, can be set to take advantage of ColorSync, or not.
The method the CMS uses to translate color from device-to-device is with Profiles, also referred to as ICC profiles. A profile describes the gamut of a device or a file. Profiles are files stored in specific places in your operating system so that they are made available to any program using the CMS. The CMS processes the source color values through the profile to create the optimum values for the destination. The way the CMS handles colors that are out-of-gamut for the destination is known as Rendering Intent. The two most useful types of rendering intents are Perceptual and Relative Colorimetric. Perceptual compresses the gamut of the source to fit into the destination, remapping all the colors to preserve their relationships as perceived by the human eye. Relative Colorimetric keeps alll in-gamut colors the same and clips out-of-gamut colors to the clost possible match within the destination gamut.
The first, most important consideration to managing the color in your photos is to have your monitor calibrated and profiled. Most devices will come with a default profile that tells the color management system how that device interprets the numbers used in digital color descriptions as compared to the human eye (called Perceptual Rendering). You need to use the correct monitor profile, printer profile etc. AND have color management enabled to get the benefits. You can either use profiles made by the manufacturers or make custom profiles yourself using specialized hardware.
An image file can have a color profile assigned or embedded to tell the CMS how to interpret the color for that image. When you choose â€œDonâ€™t Color Manage This Documentâ€ in Photoshop, you are disabling color management for that file during that working session, resulting in unpredictable results.
When you save image files, most often you WILL want to embed the profile, so that later in the workflow the other devices know what do do. However, there are cases where you may be asked not to embed the profile. In these cases however, you can still convert the colors in an image to another color space, which will often produce the same results as if the profile was embedded.
You need to know how your image file will be processed when sending it to a vendor. Ask them if there is a specific color space that they want the file in, and if they can provide you with a custom profile for the output device.
In Photoshop, you can use output device profiles to create a simulation on your monitor of how the image will appear when printed (called Soft-Proofing, see next step). However, a monitor is a transmissive device and uses photons to generate color on the screen, and a print is a reflective image made visible by light bouncing off the surface of the paper and inks, it is impossible to have a print that looks exactly like what you see on screen.
To Soft Proof in Photoshop, you open your original file in one window and a duplicate of the image in a second window. Then enable View > Proof Colors and choose the destination profile to simulate. Soft=proofing and creating customized proof conditions covered in a different article.
Â© Nathaniel D. Coalson. No reproduction without permission.
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