Scope:

The Specular gloss of materials is determined by using test methods ASTM D2457, ASTM D523. A surface’s capacity to reflect light like a mirror is termed Specular Gloss. It can be inherent in the material or affected by environmental factors such as weathering and surface abrasion or processes like texturing and molding. Gloss is directly related to the visual perception of objects equally important as color when the psychological impact of products on the end consumer is considered. Gloss is helpful in product and process development along with end-use performance testing. Gloss levels must be consistently achieved on products or different batches of products.

Test Procedure:

ASTM D2457, ASTM D523 test methods are used to determine specular gloss of material. A beam of light at a specified intensity and angle is projected, and the amount of reflected light at an equal and opposite angle is measured to determine gloss value. ASTM D2457, ASTM D523 standard requires that angle of reflection must be specified (20°, 60°, or 85°). Calibrated Glossmeter is set to the proper angle and checked with the standard supplied. The meter is placed on the test sample, followed by noting the reading.

Specimen size:

Specimens with a flat surface larger than the base of Glossmeter are used (45 × 145 mm or 1.75 inch × 5.625 inch minimum) are used.

Data:

The result is given in glass units (GU)

20° Gloss (GU)
60° Gloss (GU)
85° Gloss (GU)

Conclusion:

ASTM D2457 and ASTM D523 test methods explain the measurement of the gloss of solid plastics and plastic films and gloss on non-metallic samples.