| 摘要 |
<p>The present invention provides an apparatus for determining a parameter representing the opacity of a sample such as, the wet film hiding power, including a test plate (1) having a first portion with a first optical reflectivity and a second portion having a second, different optical reflectivity; an unit (5) which includes an optical detector (8) for detecting intensity of light reflected from the first and second portions of the test plate (1), wherein the optical unit is mounted opposite the test plate for relative movement perpendicular to the plane of the test plate and having a sample contact plate (6) which lies in a plane parallel to that of the test plate. A sample depth sensor (12, 13) is also provided for measuring automatically the depth of a sample between the test plate (1) and the sample contact plate (6) of the optical unit as the plates move relative to each other.</p> |
