calibration (Please refer to the user manual for details) 6.1 Zero adjustment and calibration）

①. Push the size pull plate (adjust R457) → → Press the "zero adjustment button" → → Place the black tube (with the opening facing up and pressed tightly) → → Press“ ↙ Key "→ → Press the" Calibration Key "→ → Remove the black cylinder and place the No.1 standard plate (ceramic side up) → → Press“ ↙ Key "→ → Calibration completed,Remove the standard board.

②. Pull out the small pull plate (adjust Ry) → → Follow the same steps as above

measurement（ Please refer to the user manual for details 7 measurement ）

Measure whiteness： Place the sample as required → → Press the "Measure" button → → MeasureR457Baidu

Measure fluorescence whiteness: First measure the whiteness → → Pull out the large pull plate → → Press the "Measure" button to measure r457 → → Press the "Calculate" button to measure the fluorescence whiteness F

Measure opacity:Pull out the small pull tab → → Press“OP... key "→ → Place the sample as required → → Press the" measurement key "to measureR0→ → Press the "↓ key" → → Place the sample as required → → Press the "measurement key" to measureR∞ →→ Press the 'Calculate' key to measure opacityO