Sheen Opacity Meter
Brand: Sheen Instruments – UK
HAND HELD OPACITY REFLECTOMETER FOR HIDING POWER, WHITENESS AND SHADE SORTING APPLICATIONS
Sheen – Opac is an easy to use, one button operation instrument ideally suited for quality control measurement in the laboratory or on site.
Virtually any surface can be measured in terms of its lightness or darkness.
Conforms to BS3900 D4 – ISO 2814 – ISO 6504/1 – ASTM E97
Sheen-Opac gives objective measurements for the hiding power of coatings and inks, and performs basic shade sorting for materials such as paper, plastics, ceramics and anodised aluminium. Using the same optical geometry as most colorimeters and an illuminant in close conformance to CIE ‘C’, it correlates well with observed results given by the human eye.
PRINCIPLE OF OPERATION
The instrument measures the diffusely reflected light from the test surface. The controlled conditions of illumination and angle of illumination allow surfaces to be characterised according to their lightness or darkness. A completely black surface will read a (zero), whilst a perfect white will be 100 units, recognised in colour measurement scale as the ‘Y’ value.
Sheen-Opac can be used for comparison of contrast ratios (hiding power) of paints. The
procedure involves applying the test sample onto black and white card (our Ref 301) or onto polyester sheets (our Ref 1136) which is then placed over black and white glass plates.
Readings are taken on the coating over the black portion followed by a reading taken over the white portion.
The readings are expressed as a contrast ratio from the formula: