This form was designed for use with the Leneta Logicator. The individual stripes produced by the TG19 Logicator are identified by “INDEX” numbers (20 to 48) engraved on the instrument. These index numbers are also printed on Form 23B in matching locations so the stripes in the drawdown can be easily identified.
Test Procedure: After the applied coating has dried, the operator locates the critical stripe, visually or photo metrically, and encircles the parameter of interest, as illustrated. It is generally accepted that the hiding power endpoint is not total visual extinction, but a degree of contrast just short of complete hiding, corresponding to a photometric contrast ratio of 0.98.
ASTM D 5007: In this standard, the hiding power of the wet film and then of the dry film are observed visually, and the percentage increase or decrease is reported.