What should I do if the contrast of the LCD display is not good?

I. Prioritize "Basic Parameter Adjustment" (the most direct and effective)

Most contrast issues are caused by improper parameter settings. First, adjust them through the system or the display's built-in functions:

1. Physical button adjustment on the display (the most precise)

All LCD displays have physical buttons (usually at the bottom or side). Locate the "Menu / Menu" key to enter the settings interface:
Find the "Image Settings" or "Display Settings" option and directly adjust the "Contrast" slider (it is recommended to start testing from 50% - 70% to avoid overexposure in the bright areas or grayness in the dark areas);

At the same time, adjust the "Brightness": Contrast controls the "difference between light and dark areas", and Brightness controls "the overall brightness of the picture". If the contrast is still gray even when adjusted to the maximum, you can slightly reduce the brightness (for example, from 100% to 70%), to reduce the interference of the screen backlight on the details in the dark areas;

Some displays have "Pre-set Modes" (such as "Standard", "Text", "Game", "Movie"), which can be switched and tried: for example, the contrast in "Text Mode" is usually higher, suitable for office work; "Movie Mode" has a softer contrast, suitable for watching movies.

2. System-level adjustment (auxiliary supplement)

Windows system: Right-click on the blank area of the desktop → "Display Settings" → "Brightness and Color" → click on "Display Brightness and Contrast" (some computers require the display to support, and will jump to the built-in adjustment interface); or adjust through the graphics card driver (NVIDIA Control Panel / AMD Radeon software): Enter "Adjust Desktop Color Settings", manually increase the "Contrast" value (it is recommended to be consistent with the physical adjustment of the display to avoid conflicts).

macOS system: Click the "Apple Icon" in the top menu bar → "System Settings" → "Display" → hold down the "Option" key, a double slider of "Brightness" and "Contrast" will appear, directly drag the contrast adjustment (mac hides the contrast option by default, need to press the Option key to show it).

II. Investigate "Hardware and Environmental Issues" (to eliminate external interference)

If the parameter adjustment does not improve, check the hardware connections or environmental influences:

1. Check the connection cables and interfaces

LCD displays commonly have interfaces: HDMI, DP (DisplayPort), VGA (old interface). The VGA interface is an analog signal, prone to interference causing blurred contrast, prioritize replacing with HDMI or DP cables (make sure the cable body is intact, without bends or breaks);
Replug the connection cables: Ensure the connectors at both ends are securely inserted to avoid signal attenuation due to poor contact (some interfaces may be oxidized, can be slightly wiped with a lint-free cloth);
Change interfaces / device testing: For example, if the display does not work with the HDMI1 port, replace it with the HDMI2 port; or connect to another computer / laptop to determine if it is a problem with the display itself or the computer's graphics card / output port.

2. Clean the screen and improve ambient light

When the screen surface has dust or fingerprints, it will reflect ambient light, causing the contrast to "visually decrease": Use a slightly damp lint-free cloth (such as a pair of glasses cloth) to gently wipe the screen (avoid using alcohol or hard cloth, as it may scratch the coating);
Avoid direct sunlight on the screen: For example, strong sunlight from a window or direct light from a desk lamp, you can pull the curtains, adjust the angle of the desk lamp, or make the screen face away from the light source (when the ambient light is soft, the contrast performance of the screen is more stable).

III. Advanced Optimization (for aging or hardware limitations)

If the above methods are ineffective, it may be that the LCD screen itself is aging (such as the backlight board decaying, or the liquid crystal molecules aging), or the hardware specifications are limited (such as the contrast of the low-end display being relatively low), in which case you can try the following solutions:

1. Calibrate screen color (improve contrast consistency) By using the built-in tools of the system or professional software for calibration, the contrast can be made more uniform:
Windows: Search for "Color Calibration" → Follow the steps in the guide, adjust "Gamma", "Brightness", "Contrast" and "Color Balance" one by one, and after calibration, the screen's light and dark gradations will be clearer;
macOS: Open "System Settings" → "Display" → "Color Calibration" → Check "Expert Mode", manually adjust the contrast and grayscale, and reduce the contrast deviation caused by color bias.
Professional software: If you have high requirements for image quality, you can use "DisplayCAL" (free) in combination with a colorimeter (such as Spyder) to precisely calibrate the contrast and color (suitable for design and post-production video users).

2. Hardware Replacement (Ultimate Solution)

If the screen has been used for more than 5 years and has problems such as "local dimming" and "uneven backlight" (for example, the bottom is darker than the top), it is likely that the backlight panel or lamp tube is aging, and the repair cost is relatively high (about 30%-50% of the display price). It is recommended to directly replace the display;

When purchasing a new display, prioritize choosing models with higher contrast parameters: The typical contrast of an ordinary LCD display is about 1000:1, IPS panel displays are recommended to choose above 1200:1, and VA panel displays can reach 3000:1-5000:1 (with more prominent dark details, suitable for watching movies and playing games). Summary

First, adjust the parameters (by pressing the display buttons + accessing the system settings). This is the quickest solution;

Then, check the hardware (cables, interfaces, ambient light), to eliminate external interference;

Finally, consider calibration or replacement (when the screen ages, replacement is more cost-effective than repair).

By following these steps, the contrast problem of the LCD display can be effectively improved, restoring the brightness levels and detail presentation of the picture.