D1834-90 – Standard Test Method Technical Guide

The ASTM D1834-90 standard outlines a test method for determining the 20° specular gloss of waxed papers. This measurement is crucial for assessing the surface shininess of waxed paper, utilizing a calibrated scale where a polished black glass standard with a refractive index of 1.540 yields a value of 100 units. The method is recognized as an American National Standard.

📐 Test Scope and Significance

This test method is specifically designed for waxed papers, as emphasized in the scope. It provides reliable correlation with visual gloss assessment when the sample maintains a flat profile. Deviations from flatness reduce the accuracy of the correlation. For book paper gloss, refer to Test Method D1223, and for very high gloss papers, see the referenced literature by Wink et al. The standard also references Practice D585 for sampling procedures and is under the jurisdiction of ASTM Committee D02.

⚙️ Apparatus and Geometric Conditions

The apparatus comprises a concentrated-filament lamp, lens system, specimen positioning mechanism, and a photoelectric receptor. Key geometric specifications include incident and reflected beams at 20±1° from the sample normal. The receptor window is circular, with a diameter that subtends a 5° angle at the sample surface. The table below summarizes critical component distances from the standard:

Additional dimensional specifications include the lamp beam lens diameter of 37 mm, specimen opening diameter greater than 25 mm, and receptor window diameter of 11 mm. The lens in the lamp beam has a diameter of 39 mm and focal length of 63 mm, while the lens at the receptor window is double convex with a diameter of 19 mm and focal length of 47 mm. The instrument must be calibrated for linearity in the cell-meter combination, and a suitable apparatus