MasterGrader

MasterGrader is designed to create repeatably identical lighting and viewing conditions for evaluating the color of gemstones in neutral "daylight" ambient light, with reference to international recommendations (CIBJO / ISO/PAS).

Key features

• Standardized daylight for evaluating the color and presentation of stones.
• Selectable shades of “daylight” light (in the range of approx. 6,500–5,400K) according to the selected configuration.
• Sample shelf places a stone in a defined position in half the distance from light sources for controlled observation geometry.
• Retractable diffuser for more diffuse conditions than direct "daylight" fluorescent lamps (useful for photography, for example).
• Individual switching of all lamps (user control).
  

Light source configuration 

1.Color evaluation (4× 8 W T5):

• Diamonds: 4× 6,500K full-spectrum daylight

• Colored diamonds: 2× 5,800K + 2× 6,500K full-spectrum daylight

• Colored stones: 2× 5,800K full-spectrum daylight + 1× 4,000K white + 1× 3,000K warm white
  
  

2. Color evaluation + UV (3× 8 W T5 + 1× 8 W UV):

• Diamonds: 1× 5,800K + 2× 6,500K full-spectrum daylight + 1× BLB 366 nm

• Colored diamonds: 3× 5,800K full-spectrum daylight + 1× BLB 366 nm
  

Variant with UV 366 nm – important note on use

The perceived intensity of UV fluorescence depends on sample distance from UV output; for comparable results it is necessary to observe constant test distance.

Technical specifications

• Variant for color evaluation: 4 x 8 W linear T5 fluorescent lamps (in parallel).
• UV variant (optional): 3 x 8W T5 + 1 x 8W T5 BLB longwave UV 366 nm.
• Power supply (standard): 220-240V / 50Hz.
• Power cable: 3-core with grounding, 2,500mm, removable fork.
• Protection class/protection class: IP20 / I.
• EMC: according to EU standards.
• Weight: 3.5 kg.
• Dimensions: approx. 34 × 40 × 15 cm (H×W×D).
• Device color: inside RAL 7016 anthracite, interior walls RAL 9006 light grey or alternatively RAL 7000 neutral grey.
• Transport note: fits in a suitcase of size 550 × 400 × 200mm (device + reflector head + accessories).
  

Package contents

• MasterGrader (configuration according to the selected variant).
• Light sources not included (lamps not included)
  

English manual-PDF