Test charts are indispensable reference tools in image quality evaluation, and their integrity directly determines the accuracy of test results. Improper use and storage environments can cause charts to fade, scratch, or deform, thereby rendering them useless for calibration.
I. Usage Guidelines
(I) Usage Environment

Test charts should be placed in a clean and tidy location, away from direct sunlight. It is recommended to use them in a “laboratory under standard illuminants.” The indoor temperature should be maintained at around 25°C, and humidity controlled at about 60% to minimize adverse environmental interference with the charts.

(II) Operating Procedures

Before handling the charts, hands must be cleaned and dried thoroughly; it is strictly prohibited to handle them with sweaty or wet hands. For further protection, it is recommended to wear gloves and a mask to prevent contaminants from hands (such as sweat and oils) from damaging the chart surface.

(III) Installation and Handling

For glass or large-format charts, single-person handling is prohibited. Multi-person collaboration is required for transportation to avoid damage or breakage caused by improper handling.

(IV) Cleaning Methods

When cleaning the charts, the use of any liquids for wiping is strictly prohibited. It is recommended to use “compressed air” to remove surface dust, preventing liquids from damaging the surface coating or material of the chart.

II. Chart Maintenance and Replacement Due to Aging

(I) Chart Types

Black-and-white charts: Charts without colors, typical examples include the ISO 12233:2000 resolution chart and checkerboards.

Color charts: Charts with colors, typical examples include the ColorChecker, suitable for scenarios such as “color accuracy testing.” (II) Inspection Methods

Generally, color measurement devices and densitometers are used to check the condition of the charts. Quantitative data (such as color deviation, spectral reflectance, etc.) is used to evaluate whether the charts require maintenance or replacement. (III) Replacement Cycle

Black-and-white charts: It is recommended to replace colorless charts every 2 years.
Color charts: Since colors are susceptible to environmental influences, it is recommended to replace color charts every 1 year.
Special circumstances: If the pattern area of a chart shows damage, scratches, dirt, missing parts, wrinkles, or other issues, it must be replaced immediately to avoid affecting test results.

III. Storage Guidelines

(I) Basic Environmental Requirements

Test charts should be stored in a clean, dark, and dry area. The temperature should be maintained at around or below ~23°C / 72°F, and humidity must be strictly controlled to avoid the negative impact of damp environments on the charts.

(II) Key Factors Affecting Storage

1. UV and Light Exposure
UV radiation is the biggest killer, as it can directly break down pigment molecules, leading to a decrease in chart contrast and saturation, as well as fading. Direct sunlight is the most destructive due to its high intensity and high UV content. Even indoor visible and infrared light can cause cumulative damage over prolonged exposure, albeit to a lesser extent.

2. Temperature and Humidity
Significant thermal exposure (e.g., >52°C/125°F) can degrade dye structures and accelerate the fading process. High temperatures are extreme conditions that must be avoided. Additionally, humid environments can cause issues such as mold, warping, or delamination of the charts.

3. Environmental Pollutants
Airborne pollutants, especially ozone, can chemically react with chart materials. Note that certain environments (such as workshops with laser equipment or motors) may generate ozone, so charts must be stored in isolation.