Color Management
Step 1: Calibration & Profiling
The Problem:
Your camera, computer monitor, projector and printer each displays the same color slightly differently. For example, a person’s face (which is a particular shade of red) imaged by your camera may appear to be too yellow on the monitor, too green in the projector and too orange in the printer. Said another way, a specific face color might be represented with too little blue by the monitor, too much green by the projector, and not enough cyan by the printer. Other colors may also be misrepresented by each device.
The Solution:
Calibrate and profile your monitor, projector and printer so that each device can accurately represent a set of standard colors. This will ensure the closest correspondence of colors between the devices. You can also do this for your camera, but after getting an image, most of us want to change the colors and color balance in post processing to achieve a ‘look’, which will circumvent any color calibration of the camera. So, we usually don’t bother to calibrate and profile our cameras. In post processing, we rely entirely on the computer monitor to accurately represent color. If the monitor is not calibrated and profiled, the chances are that it is not as accurate as it can be, and the same can be said of projectors and printers.
The Process:
1. Buy an appropriate calibration device. Calibration software is included.
For Monitor, printer & projector: Calibrite ColorChecker Studio or Spyder Print Studio. For Monitor & projector (ie. you don’t make prints): Calbrite Display Pro HL or Spyder Pro.
2. Disable settings in the Windows or MAC OS that automatically change the monitor’s brightness or color. More details are available in the first video playlist listed in the ‘Videos’ section below.
3. Use the software & calibration device to calibrate and profile your monitor (and projector and printer, if you own them). Instructional videos are listed in the ‘Videos’ section below.
What is Calibration and Profiling?
Let’s use the computer monitor as an example. Buttons on the side, bottom or back of the monitor will switch on the on-screen display (OSD) or menu, providing access to controls for adjusting brightness, contrast, and RGB color. (Projectors usually have an OSD, too.) Calibrating the monitor means making these adjustments so that they are as close as possible to a standard. Standard test patterns are displayed on the screen while the monitor’s OSD is used to adjust brightness and contrast. Calibration software, a calibration device and the monitor’s OSD color controls are used to adjust the monitor’s R, G & B color balance as close as possible to 6500 degrees K (D65). These adjustments may not be fine enough to be perfect. Even after calibration, the monitor’s electronics usually cause imperfections in the monitor’s display of thousands of different colors. So, the additional step of profiling is necessary.
Profiling is the process of using the calibration software and the calibration device to make a lookup table (LUT) that lists corrections for the discrepancies between true standard colors and the colors that the calibrated monitor displays. These corrections are stored in a file with an .icc or .icm extension, and the file is called a monitor profile. The corrections in the .icc or .icm profile file are used by the computer’s operating system (Windows, Mac, Linux) to alter the RGB color signals sent from the graphics processor (GPU) to the monitor, so that the monitor displays standard colors accurately.
How Often Is Re-calibration & Re-profiling (R&R) Necessary?
With monitor use over time, the specs of electronic components inside the monitor change slightly, and that changes color accuracy. Therefore, it is usually recommended to R&R every 1-3 months, depending on monitor use. Some professionals R&R at the start of each project. In printers, color accuracy depends on ink cartridges and paper stock, so any change of these components usually requires R&R.
Step 2: Set Color Spaces in Camera RAW, Lightroom & Photoshop
Color Spaces:
A color space is a subset of all the colors that human vision can perceive. The smallest subset, called the sRGB color space, is used to display color image files on the Web, phones, tablets and computer monitors, and is also used by most professional printers. Slightly larger subsets, the Adobe RGB and Apple Display P3 color spaces, contain more colors and are used by some mid-range & high-end computer monitors, digital printers and some professional printers. These color spaces were developed to improve photo editing and to display a slightly larger range of colors (gamut) compared to sRGB. A detailed comparison of sRGB, Adobe RGB and Apple DIsplay P3 can be found here. The largest color space, called ProPhoto RGB, developed by Kodak for photographers, includes almost all of the colors that humans can perceive. Currently, there are no devices that can display or print the ProPhoto RGB gamut. More details about color spaces are described here and in this video.
In photography, the camera usually assigns a color space to each jpg image, according to settings chosen in the camera’s menu. Each jpg image file has the code for a particular color space embedded into the file. RAW files, however, do not have a color space assigned to them or embedded into the file. After importing and processing a RAW file in a RAW file editor (e.g. Adobe Camera Raw, Lightroom), the product can be assigned a color space before being saved as an image file (e.g. TIFF, PSD, DNG, jpg, etc) or before being exported (as a TIFF or PSD file) to an image editor like Photoshop.
Color space codes are embedded into image files to instruct the OS, photo editing programs, slideshow programs and printers, etc. how to interpret the color data. Without the embedded color space code, the file is ‘untagged’ (not color managed) and the software has to guess how to display or print the color data, which may lead to a poor result.
Which Color Space Do I Use?
Practical advice about which color space to use when editing and saving images for various destinations is presented in this video.
Setting Color Spaces in Camera Raw, Lightroom & Photoshop:
This video explains how to properly set color spaces in Camera RAW, Lightroom and Photoshop. The specific instructions for Camera RAW begin at the 5:44 minute mark, Lightroom instructions begin at the 7:36 minute mark, and Photoshop instructions begin at the 0:51 minute mark.
A more advanced view of choosing and setting a color space in Photoshop is presented in this video. NOTE: In Photoshop, some color setting windows (ie Convert to Profile, Assign Profile) refer to color spaces as ‘profiles’.
Search
Articles
Overview of Color Management
Monitor Calibration for Photography
Soft Proofing
Soft Proofing in Lightroom
Soft Proofing in Photoshop
Videos
Monitor Calibration Playlist (Calibrite/X-Rite). View all videos in the playlist that are appropriate for your equipment.
Monitor Calibration (Spyder)
Projector Calibration (Calibrite/X-Rite)
Printer Calibration (Calibrite/X-Rite)
Printer Calibration (Spyder)
Match Prints & Monitor (Calibrite/X-Rite)
Calibrate All Photography Devices (Calibrite/X-Rite)