Screen contrast – a technical guide

Image contrast is one of the most important features that determine the quality of the displayed image. The correspondingly high screen contrast provides crisp detail, depth of blacks and vivid, saturated colors. On the other hand, too low a contrast makes the image pale, hazy and difficult to view. In this article, we will explain what dynamic contrast is, what types of contrast there are, how to measure and adjust screen contrast, and how it affects the visual experience.

Contrast of displays in industrial equipment

Contrast is also crucial in specialized devices used in industry, medicine and the military with screens and displays. For example, the high contrast of touch screens on PLCs and HMIs ensures readability and makes it easier to operate machines and production lines. It is similarly important in medical monitors supporting surgical procedures or in mobile military terminals. The high contrast enables precise operation and fast response, essential for many critical industrial applications. Therefore, dynamic contrast parameters are crucial in the design of specialized touchscreen and display devices.

Types of contrast

Screen contrast can be determined in a number of ways, depending on the matrix technology and the way the image is displayed. The most important types of contrast are:

• Static contrast – the ratio of the brightness of the brightest and darkest parts of a fixed, still image. The higher the static contrast, the greater the difference in luminance between white and black, and thus the better the readability and clarity of details in the image. Typical static contrast is about 500-3000:1.
• Dynamic contrast – determines the ability of the display to achieve high contrast in rapidly changing scenes. It is achieved by dynamically controlling the backlighting of the matrix. It allows to achieve high quality dynamic contrast – in the order of tens of thousands to 1million:1.
• The contrast of plasma screens – characteristic of plasma displays, is due to the way the image is formed by the gas cells. It can reach very high values, even a million to one.

Effect of contrast on image quality

The higher the screen contrast, the better the quality and comfort of the viewing experience. High contrast provides:

• excellent blacks – dark scenes and shadows are deep, without a gray glow;
• richness of gray tones – tonal transitions are smooth, with plenty of detail;
• Vibrant colors – colors are saturated, vivid, well reproduced;
• Sharpness and clarity – the image is sharp, detailed, without blurring;
• No tiresome halo effect – the contours of objects are clear, without flare or glow.

Contrast also affects viewing comfort. Too low a contrast causes eyesight fatigue faster, as it is tiring to constantly strain to see details in a pale image.

Contrast-enhancing technologies

To get the best dynamic contrast on TV, various advanced technologies are used, such as:

• Local dimming – a technique used in LCD TVs with LED backlighting, which involves dividing the matrix into zones and controlling their brightness independently. Allows you to get a perfect black.
• HDR (High Dynamic Range) – a technology that allows to cover a much wider range of luminance, resulting in a higher contrast image with more detail in the light and dark areas.
• DCR (Contrast Ratio) – dynamic contrast control, optimizing image brightness from frame to frame for a very high contrast experience. ACR dynamic contrast what is it? It’s actually the same as DCR, it’s just that some manufacturers have their own terms, like just ACR (Advanced Contrast Ratio).

Measuring and expressing contrast

Dynamic contrast in a monitor is usually given as a ratio, such as 3000:1. This means that the brightest parts of an image can be 3,000 times brighter than the darkest parts. It is also often given the so-called. dynamic contrast ratio, such as 50,000:1, which does not reflect the actual contrast, but only the maximum ability of the display to control luminance.

Actual image contrast depends on many factors, such as ambient brightness and display settings. Therefore, when buying equipment, it is advisable to be guided primarily by visual impressions, and not just by the numbers on the specifications.

Factors affecting contrast

Perceived image contrast is also affected:

• Ambient lighting – the stronger the light falls on the screen, the lower the contrast appears. For best results, viewing in a dark room is recommended.
• Image settings – proper calibration allows you to optimize contrast by adjusting brightness, contrast, gamma and other parameters.
• Viewing angle – the best contrast is obtained at the optimal viewing angle of the screen, usually slightly from the top down.

Applications of contrast

Image contrast is crucial in many areas:

• Monitors and TV – a key feature that determines image quality. Contrast parameters are fundamental when choosing a display.
• Photography and graphics – contrast determines the depth of blacks, clarity of details, and saturation of colors in photographs and graphic designs.
• Web design – proper contrast makes text easier to read and increases the readability of the site.
• Medical diagnostics – high contrast imaging allows subtle nuances to be seen on medical displays, such as. When analyzing an X-ray.

Contrast vs. eyes

Poor image quality with low contrast can cause eyesight fatigue faster. Viewing such an image requires straining and concentration, resulting in increased blinking and tearing. Prolonged observational effort causes fatigue in the muscles responsible for accommodation. Therefore, the LCD’s high dynamic contrast significantly improves the viewing experience.

Contrast Tips

To enjoy the image with the best possible contrast, it is worth:

• Ensure good lighting conditions at the image viewing site.
• Adjust image settings to optimize contrast and black depth.
• Position yourself centrally in front of the screen, preferably slightly below its center.
• Take regular viewing breaks to relax your eyesight.
• Static versus dynamic contrast? We recommend dynamic solutions.
• Dynamic contrast which is better? It is worth choosing a monitor or TV with the highest possible contrast.

In summary, image contrast is a key parameter that directly affects image quality and viewing comfort. The corresponding high dynamic screen contrast provides an image with vivid colors, crisp details and deep, dark blacks. Therefore, when choosing a display, it is worth paying attention to this aspect.