Here's a great post by my friend Leo Geis on his Forensically Fit website regarding Color Management Fundamentals with Photoshop. Leo does a wonderful job explaining very complex issues on his webpage:
Devices reproduce color inconsistently. Inaccuracies in color are a forensic liability.
"Color Management" refers to the procedures and tools used to control color so that it displays as accurately as possible on each device or output artifact (print). It's important to note that consistency without accuracy is of little value in most forensic applications, and that it is necessary to quantify accuracy to prove it. It is also important to remember that the human visual process of images is uncertain/unstable on its own-Color Management does not directly attempt to compensate for variables in human visual acuity.
A common example of the problem that Color Management is meant to resolve is the inaccurate and inconsistent display of images on monitors. If you view the same image on two different monitors they will probably be noticeably different, much as in the following graphic:
The image on the left offers more contrast (the difference between the lights and darks) and a red bias (producing the purple sky) as compared to the image on the right, while the image on the right shows a drastic lack of saturation. These are very common distinctions in the output of monitors.
Prints can produce even more inaccuracy and variance: prints rely upon a particular media (paper), dyes or pigments, and the vehicle that those dyes or pigments are suspended in for their color.
Printers are also inherently inconsistent-even printers of the same manufacturer and model may differ significantly in their performance, particularly when temperature and humidity are fluctuating.
Printers are also inherently inconsistent-even printers of the same manufacturer and model may differ significantly in their performance, particularly when temperature and humidity are fluctuating.
There's another critical element of viewing (aside from varied human visual acuities) images, and that is the nature of the ambient light. Different light sources produce distinct lighting characteristics, and while monitors produce their own light prints rely upon ambient light (reflecting some and absorbing some) for their function. If prints are viewed under different lighting sources they will most certainly appear dissimilar. Please refer to this previous post on Forensically Fit™ for a brief explanation of the Color Temperature of Light.
In order to produce accurate color during each step of the image production process it is necessary to account for the inaccuracies explained above, and to control the output of the various devices used in the process. In short, Color Management involves esoteric Color Science and Color Theory, strange devices with intriguing names such as "Colorimeter" and "Spectrophotometer," as well as an understanding of the context in which Color Management is employed: it is used in textiles, automotive finishes, textbook publishing, leather dyes, paint, photography and videography, flooring, corporate logos, medical imaging...virtually anywhere that color itself is important.
Because Color Management involves very complicated aspects of Color Science and equipment, it is important in the forensic context to acquire bona fide expertise to either establish or impeach visual artifacts in investigations, mediation/arbitration, or trial.
The fundamental tool in Color Management is called a (Device) Profile: that will be the topic of our next posting.
L
