What is Monitor Contrast Ratio? Monitor Contrast Ratio is defined as the ratio between the measured darkest black and measured brightest white which display produces. This is what we call the contrast ratio of the monitor.
The monitor contrast ratio is always expressed in the form of a ratio. For instance 3000:1 and reads as “three thousand to one”.The contrast ratio of the monitor will be higher if the first number of the ratio is higher and also if the difference between dark black and pure white will be more.
Importance of Monitor Contrast Ratio:
If the range between the darkest black and brightest white is wide enough, then the monitor will be capable of deep and rich colors and there will be more observable details in highlights as well as in shadows. And this will be helpful if the monitor is used for editing purposes of photos and videos, also for graphic designing, for watching movies and for playing games.
This contrast ratio of the monitor is also helpful in detecting minor differences that may occur in the color or brightness of monitors.
Hence, it is an important aspect of the quality of pictures of monitors.
The contrast ratio of the monitor is one of the main parts of the quality of the picture of monitors. The differences between measured dark black and measured pure white with backlights of the lowest and feasible setting while the monitor is powered on. The higher the contrast ratios would be there, the deeper the blacks will be and will make a great difference in the quality of monitor pictures. It’s of vital importance for the screens which are dark while playing movies plus games especially when we are sitting in a dark and dull lighted room.
The mathematical equation for monitor contrast ratio:
Contrast ratio=white luminance ÷ black luminance
So if we are interested to find the contrast ratio of our monitor then we have to divide white luminance by black luminance of our monitor and the answer we get will be our contrast ratio of our monitor.
Unit for a contrast ratio of monitors:
Since the monitor contrast ratio is the ratio between two similar things with just the difference of lights, so there is no specified unit for it. So we can say that there is no unit for expressing the monitor contrast ratio.
Negative contrast ratio:
This is another term used in monitor contrast ratio and it represents the most important and basic monitor contrast ratio. It is concerned with less amount of processing of images and also for those features which are designed for improving the monitor contrast ratio disabled, for example, local diming.
Measurement of negative contrast ratio of monitors:
Measuring the negative contrast ratio of our monitors, we have to use the checkerboard of both dark black and pure white luminance. For example, pure white luminance closest to 100cd/m2, plus seven measurements of luminance by using LS-100 meter of luminance, can help us in calibrating the monitor.
Pure white luminance, it is necessary to be closest to 100 cd/m2, and for dark black luminance, it is necessary to measure that luminance for each of 4 blackest squares that surround central White Square. This will reduce the effect of the uniformity of black on our measurement of contrast ratio of our monitors.
Local dimming contrast versus negative contrast:
Contrasts for local dimming are somehow identical to negative contrast ratio but there is the difference in both of them that in local dimming contrast, we have to measure contrast ratio of local dimming of the monitor while feature enabled. Monitors with multiple local dimming, we have to use the setting which is recommended and also based on the results of local dimming tests. This is mostly the highest setting being available.
Monitors lacking local dimming:
Mostly, monitors are not having a feature of local dimming although it is expected that monitors with local dimming are more and more common for instance displays of HDR are mostly popular. So for those monitors that do not have local dimming, it is better to set N/A. Local dimming is only available in HDR, so we have to measure the SDR contrast ratio on those monitors where we cannot measure the contrast ratio with local dimming.
Ways for measuring contrast ratio:
There are various ways of measuring the contrast ratio of monitors.
We can measure monitor contrast ratio by using a checkerboard pattern and by taking the level of average black from four squares.
We can measure the contrast ratio by using a full white screen and also full black screen. Although it is expected to be a less accurate way for measuring monitor contrast ratio and also this way is not very realistic. This way is called full on/off.
By using the above method but by showing one slide half of the black screen and half of the white screen, we can measure the contrast ratio of our monitors. This method is somehow realistic and more reliable than the full-on/off method. This method is called the half screen slides method. Another method used for measuring contrast ratio is Small samples, in which instead of using large slides, contrast is measured by using small slides that just cover the part of the screen. This method is relatively better than the above-mentioned methods.
Another method which is a more realistic method than all the above methods is ANSI checkerboard and it is expected to be the most accepted way of measuring monitor contrast ratio. In this method, we have to use asymmetric test patterns. It measures the output of all 16 squares and also the average values of white and black squares.
From the above discussion, it is proved that the monitor contrast ratio is a vital thing which indicates the depth of deep blacks because the higher the contrast ratio is the higher will be the deeper blacks and better quality of the picture. This contrast ratio is an important part of the picture quality of monitors. This contrast ratio helps us in getting a good monitor with good contrast and also of good picture quality. So we can say that the monitor contrast ratio is one of the most important properties of the display system.