PHOTOVOLT TECHNICAL NOTE
577 Measurements For Opacity Of Paper

SEARCH UNIT IN UPRIGHT POSITION

PHOTOVOLT 577 SETTINGS

1. Use a PHOTOVOLT 577 with a Y or a T search unit.

2. Use a green tristimulus filter.

3. Use the GREEN channel on the PHOTOVOLT 577.

4. Use the opacity plaque without the plaque holder (remove from holder by loosening screws).

5. Allow the instrument to warm up for 30 minutes to stabilize.

MEASUREMENT

1. Zero the meter using the black cavity standard.

2. Place the paper sample on top of the search unit, back with the OPACITY PLAQUE and put a value of 99.9% into the instrument by pressing the CHANGE and STD KEYS.

3. Press the STD key to place this value in the PHOTOVOLT 577 memory.

4. Remove the white OPACITY plaque and replace with the black cavity standard.

5. Read the % R on the display.

SEARCH UNIT IN INVERTED POSITION

PHOTOVOLT 577 SETTINGS

1. Use a PHOTOVOLT 577 with a Y or T search unit.

2. Use a green tristimulus filter.

3. Use the GREEN channel on the PHOTOVOLT 577

4. Allow the instrument to warm up for 30 minutes to stabilize.

MEASUREMENT

1. Place a black velvet swatch or the black velvet zero standard for gloss (PHOTOVOLT 26057512) on a flat surface and cover with the search unit held in the inverted position and zero the meter.

2. Place the paper sample on the white OPACITY PLAQUE (without the plaque holder) and cover with the search unit in the inverted position.

3. Place a value of 99.9% in the instrument using the STD and CHANGE keys.

4. Press STD to place this value in the PHOTOVOLT 577 memory.

5. Transfer the paper to the black velvet swatch or the black velvet zero standard for gloss, place the search unit on top of the paper and read the % R on the display.