| Calibration vs Profiling |
|
Calibration is basically the process of bringing any device such as a precision measuring instrument, scanner, printer or even a monitor into a known state. As for the case of the monitor, this calibrated state is generally thought of in terms ofadjusting white point, brightness and/or contrast to within desired pecifications. Monitors (both CRT and LCD) can drift out of their calibrated state for several reasons, some of which are the amount of time being used or lack thereof, attaching the monitor to a different computer, physically moving the monitor from one corner of the room to another, and even users believing they are improving their image by changing settings. Any of which can cause the device to display or perform in an uncalculated manner. Essentially the process of calibrating a monitor is an attempt being made to bring the fore-mentioned white point,brightness and contrast levels to a repeatable level of adjustment. This has absolutely nothing to do with the color of the image that is being displayed or the software program being used to manipulate the image. Normally a calibration process displays a number of neutral gray squares or "patches" on a rectangular field of a neutral band of density, ranging from absolute black to absolute white. The object is to get the patches to visually display without color cast and to ensure that there is separation between the blackest patches and the whitest patches. A search on the web will provide for some crude yet interesting methods of monitor calibration. Once again, this attempt at adjusting your monitor is a good start at the WYSIWYG process and is better than nothing but is far from the completed process. Profiling is the process of getting a description of what color is capable of being displayed. For example, a graphics house or a photographer has two monitors of the same model, brand and manufactur edate. The displays will probably differ from each other due to their individual characteristics even after the same calibration process. In the attempt to get the to monitors to "look" the same, these characteristics need to be described, calculated, and then compensated for to accurately display color and density with respect to each other. This calculated description is known as a profile and resides in the OS (operating system) of the computer. Standards of profiling have been set up through the ICC(International Color Consortium) so that matching one display to another will be closer although rarely exact. Programs that are ICC compliant access the profile that resides in the OS and will display images through that profile to compensate for the characteristics of the monitor. Adobe Photoshop immediately accesses the OS and reads the monitor profile in order to ensure an accurate and consistent display. Hence, if using Photoshop, it is almosta necessity to create a monitor profile. During the profiling process, it is essential that the monitor be calibrated first so that the possible variables of the profile are kept to an absolute minimum. Programs that are used for profiling make use of software and/or a hardware combination and will have some kind of calibration process. The calibration is normally based on numerical data rather than visual. This is to keep the subjective influences such as weak color analysis or the inability to distinguish subtle differences in tonality or gradation, out of the calibration process. |
| < Prev | Next > |
|---|