Monitor Calibration and Printer Calibration
The BeerColor.com photographs of malts and their color swatches have been calibrated so that they can be viewed at their true color.
With this sites theme of color being variable in each setting, I wanted to provide an area of discussion on monitor and printer calibration. This is very important for color analysis in the laboratory and in the field of photography. Each participants needs to be assure that he is viewing the same color as the next person. The artist wants to make sure their presentation is reproduced and seen as intended. If I sent you an image and our printers and monitors were not calibrated, we would not view the same colors. Color calibration is an immense subject that I wish I could be more knowledgeable about. I had planed to write several pages on calibration and correction - however there are so many knowledgeable persons that offer their expertise on the web. So to obtain a greater knowledge on these subjects I will provide several links to divert you to this knowledge.
Norman Koren, the founder and president of Imatest*, and has been involved with photography since 1964. He holds a AB in physics from Brown University and an MA in physics from Wayne State University. His previous career in magnetic recording technology has provided him with an outstanding background for image quality analysis. Currently he is doing camera testing of several Phase One medium format backs and producing image quality testing software.
Norman lives in Boulder, Colorado where he can occasionally be found with a Jeremiah (Irish) Red Ale in hand at BJs Restaurant and Brewhouse.
The chart below enables you to set the black level (brightness) and estimate display gamma over a range of 1 to 3 with precision better than ±0.1. The gamma pattern is on the left; the black level pattern is on the right. Before using the chart, the monitor should be turned for on at least 15 minutes (30 preferred). For flat screen (LCD) monitors, Screen resolution (right-click on the wallpaper, Properties, Settings) should be set to the monitor's native resolution.
Gamma is estimated by locating the position where the average luminance across the gamma pattern is constant. The corresponding gamma is shown on the left. You should be far enough from your monitor so the line pattern is not clearly visible. The example below shows what to look for. The solid areas are calculated from the equation,
pixel level = 255*luminance(1/gamma) ; luminance = 0.5.
2.2 is recommended for Windows, the Internet sRGB color space, and the popular Adobe RGB (1998) color space. Most laptop LCD screens are poorly suited for critical image editing because gamma is extremely sensitive to viewing angle.
Black level (brightness) Your monitor's brightness control (which should actually be called black level) can be adjusted using the mostly black pattern on the right side of the chart. This pattern contains two dark gray vertical bars, A and B, which increase in luminance with increasing gamma. (If you can't see them, your black level is way low.) The left bar (A) should be just above the threshold of visibility opposite your chosen gamma (2.2 or 1.8)-- it should be invisible where gamma is lower by about 0.3. The right bar (B) should be distinctly visible: brighter than (A), but still very dark.
There is considerable interaction between the brightness and gamma settings-- increasing brightness decreases gamma-- so you may have to go back and forth two or three times. There is less interaction between Contrast and gamma. The vertical bars correspond to normalized luminances of 0.002 and 0.006 at the specified gamma.