What is calibration? Why do I need it? Could I do it myself? How does it help?

These questions and more can be answered by reading the following article, written by NOLA Smart Wire's owner, Jeremy Sauer. More questions about HDTV calibration can be answered by emailing or calling Jeremy.

Telvisions, HDTVs particularly, do not come out of the box with their color representation looking correct. Typically the televisions have the brightness and contrast turned all the way up. The reason for this is that in a typical big-box store, florescent lights illuminate the place. It is hard for televisions to compete with an over-lit environment. The brightness and contrast setting make the televisions stand out against the ambient light. There is a natural tendency for human eyes to be attracted to the brightest television on the wall of a store. Because of this, television manufacturers place in the user menu one setting often called "vivid" or "dynamic." This is with brightness at 100% and contrast often at 90%. This is one of the worst settings to have in your home for a number of reasons. The contrast will wash out distinct white colors, the brightness setting will make black colors resemble gray. A bright screen of this kind will also tire out your eyes, literally putting a viewer to sleep that wouldn't be tired if the brightness and contrast were set correctly. The power consumption increases when whites are pushed to their limits, and the lifespan of the television itself is impacted by these settings.

An organization named the Imaging Science Foundation, or ISF, was formed in 1994 to combat these inaccurate settings that televisions came programmed with. Movie producers and directors often spend millions of dollars during the production of a movie to get the most accurate colors that can be reproduced on the screen. If your television is in "vivid" or "dynamic", they wasted their money trying to show you a quality picture at home. The ISF was incorporated in 1994 by Joel Silver, the founder and owner of ISF. He works with manufacturers, dealers, technicians, and marketing employees. The goal is to teach both the television manufacturers and licensed technicians how to make the pictures on the television screens everywhere be as accurate as possible. Training is a multi-day hands-on approach in a room filled with different brands of televisions. Accuracy is judged on the Kelvin scale, with 6500 Kelvin being the standard. The number 6500 refers to the temperature (measured in degrees Kelvin) at which a specific theoretical material (referred to as "black body") will glow the color of sunlight at noon. Developers of the NTSC system adopted 6500 degrees Kelvin as their system's reference standard. DVDs and the ATSC (high-definition TV) system use 6500 as well.

Here are the services included in a typical calibration: Set grayscale to the NTSC standard of 6,500 Kelvin, improving color accuracy of the entire palette; set contrast, brightness, color, and so on using test patterns designed specifically for each of these controls; optimize overscan and picture position, enabling display of more of the incoming picture; correct red push in the color decoder when possible; optimize all DVD input sources using DVD test patterns and HDTV input using an HDTV test-pattern signal generator.

Newer televisions sometimes ask during initial setup if this television going in the store or in the home? If your television asks you this during the initial setup and you answered home, it will not put the television on vivid or dynamic. If you were not asked this question, most likely the user mode in the user menu is on one of these difficult to view settings.

What is it that an ISF calibration accomplishes? An ISF certified calibrator will come to your home (this kind of calibration can only be done onsite as explained later) with several DVD/Blu-ray discs, a video generator, a Colorimeter (contact or non-contact), a computer and software to analyze the equipment's findings. The first step should always to take a pre-calibration capture, determining where your television is on the scale before any work is done. From here, the technician should check all of the connections to the television to determine how everything is connected. Inside the user menu of the television, the technician should check all of the possible settings for both the user setting and color temperature. Either using their eyes or the test equipment, the color temperature setting closest to 6500k should be selected. The user settings including Brightness, Contrast, Color, Tint, and Sharpness should be tackled next. Using the Video Generator and possibly using blue, red, and green filters, all of the user settings should be adjusted. Depending on the age of the television, the technician may have to enter the service mode of the television or may be able to make the "white balance" settings within the user menu. This is determined by the make, model and age of the television. "White balance" or "grayscale" is best described with a painter's analogy. When a painter paints on canvas, even if the oil paint is accurate in color, the picture will be effected by the color of the canvas. If the canvas begins pink, the overall colors put on the canvas will be effected. It is the same with a television screen. Since screens are made up of a combination of red, green, and blue colors, too much red compared to green and blue will cause the initial white to be more pink and will thus cause all of the colors put onto the screen to have a red/pink hue. White balance will set the blue, green, and red in perfect harmony to each other in comparison to the 6500k scale. This setting is usually done with a colorimeter connected to a video generator and a computer. The colorimeter tells the computer what adjustments need to be made to reach a perfect x and y reading of white at 6500k as shown on the CIE color chart. X is located a horizontal axis of 0.313 and y at a vertical axis of 0.329. The balance on televisions needs to be made according to the low and high IRE settings in the gray scale control, either in the user menu or in the service menu. A zero IRE screen should refer to a black screen on the television while a 100 IRE screen is the bright white screen. In order to correctly calibrate the while balance, the calibration must be performed once at a high IRE, possibly 80, and again at the low IRE, possibly 20. The newer televisions use terms such as Gain, Drive, White, Contrast, High, and even v15 to describe the high IRE settings. Words to describe the low IRE include Bias, Cutoff, Black, Brightness, Low, and Offset. When the video generator sends an 80 IRE picture to the screen, adjustments are made to the high IRE settings. When the generator sends a 20 IRE picture, the low IRE settings are adjusted. After each round of adjustments, the contrast, brightness, and low and high IRE settings have to be rechecked, as an adjustment to any of them may have an effect on the other. Once balance is achieved, the setting for that time of day is made. While still in the service menu, the calibrator should view an overscan percentage screen and adjust the televisions horizontal, vertical, and overscan settings to have your television display as much of the incoming picture as possible.

During a proper calibration, each input used must be individually calibrated. While it seems that HDMI2 would use the same settings as HDMI1, this is very often not the case. Component video, composite video, S-video, and DVI are also not equivalent. Each input should be individually set.

The difference in inputs is similar to the difference in televisions. LCD panels are made in production facilities in the far east. Often times, the fifth LCD screen produced has very different color reproduction compared to the 1000th screen produced. In fact, there can be color differences between each of the screens produced on the LCD production line. No screen looks exactly like another, and the inputs used in these sets often vary, even with the digital inputs, in the colors they reproduce.

Many people try to calibrate their televisions using the "best settings" for their television that they find on the internet. This does not work however, as every viewing environment is different. A home theater room with bay windows on the west in California with white walls is about as different a viewing environment as an east-coast abode with a home theater facing east with curtained windows and dark walls. Every environment has different ambient light, different wall shades, and different reflective colors. For this reason, professional calibration of your HDTV may be completely different than someone elses.

Which brings me to the end result. There will be two different settings left by your calibrator. One is for daytime viewing, when ambient light can seep into the room. This picture obviously has a different brightness setting, needing it to be a little brighter than nighttime viewing. The second is the night setting, which compensate for the rooms lighting rather than daylight. Once your calibrator is finished, test discs should be viewed by them and shown to you showing just how much the correct color can make a difference and how much better your television reacts with the proper white balance/gray scale. A post calibration capture should be taken by their software and a report should be given to you once they have a chance to print it.

My Calibration Report will show: 1. A pre-calibration and a post-calibration CIE chart. 2. Color temperature pre-calibration and post-calibration on a 6500k chart. 3. Color error pre-calibration and post-calibration for each of the IRE levels 0-100. 4. RGB tracking pre-calibration and post-calibration. 5. Luminance tracking in FootLamberts from 0 IRE to 100 IRE (shows peak brightness of your screen pre-calibration and post-calibration. 6. Gamma tracking. 7. Color Gamut pre-calibration and post-calibration.

Contact me with questions or additional subjects about ISF calibration that you think I should describe.

Jeremy Sauer