Precautions for Using Pressure Test Films (During Pressing and Testing Stages)

Pressing Stage

1. The L sheet is extremely sensitive to even light pressure. Do not press, rub, or mishandle it before use. Handle gently.
2. The color-forming substances inside the microcapsules may adhere to hands. Prolonged contact may cause skin irritation in sensitive individuals. It is recommended to wear gloves while handling.
3. Recommended environmental conditions: 20°C–35°C, 35%–80% RH. Using the film outside this range may affect the accuracy of pressure measurements.
4. The color on the K sheet may vary depending on temperature, humidity, and pressing conditions.
5. If water, oil, or other foreign substances attach to the coating surfaces of the L or K sheets, color development may be impaired. Ensure the measured surface is clean before use.
   • Special environmental precautions:
     a. For prolonged high-temperature pressing, add insulating material outside the film to prevent the sample from being affected by heat.
     b. In water or oil environments, place the film in a waterproof and oil-resistant bag before pressing to prevent contact with water or oil, which may affect color development.
6. Used pressure test films cannot be reused.
7. Use the film within its shelf life.

Testing Stage

• It is recommended to measure density 30–60 minutes after color development. After pressing, the color density will initially increase gradually and then slowly decrease over time.