Paper and board — Measurement of specular gloss — Part 1: 75 degree gloss with a converging beam, TAPPI method

Scope:

This part of ISO 8254 specifies a method for measuring the specular gloss of paper at an angle of 75° to the normal to the paper surface. Although its chief application is to coated papers, it may also be used for glossy uncoated papers such as supercalendered papers.

NOTE 1 This method does not provide an assessment of image-reflecting quality and should not be used for castcoated, lacquered, highly varnished or waxed papers or for high-gloss ink films. For these purposes, measurements at other angles, for example 20°, are preferred, although the present method has been shown to be suitable for gloss measurements of most other ink films on paper or paperboard. Differences in the colour and the diffuse reflectances of these ink films have a negligible effect on gloss measured according to this part of ISO 8254. For example, measurements on white and black surfaces which are otherwise identical give a value for the white surface that is less than one gloss unit higher than the value for the black surface.

NOTE 2 The methods specified in ISO 2813, Paints and varnishes - Determination of specular gloss of non-metallic paint films at 20°, 60° and 85°, may be applicable to certain grades of paper.