A new apparatus (dynamic scanning absorptometer ; DSA) has been developed for analyzing short-time liquid absorption behaviors of paper. It involves a computer-controlled turntable mechanism holding the paper specimen, onto which a liquid supply head is contacted. The rate of liquid absorption is measured by optically tracking the motion of meniscus in the glass capillary connected to the supply head. The results are analyzed and graphically displayed by computer in real time. Thus the apparatus provides a quick (5-15 min for an entire plot) and fully automated version of the Bristow absorption measurement, using a single sheet specimen of ca. 20 cm × 20 cm. The results of DSA measurement using distilled water and dilute dye solutions agreed well with each other and with those of the Bristow measurement, except for 10-20% greater values with the former in the long contact time regions for the hardsized paper. This discrepancy is considered to reflect overestimation of wetted area in the Bristow measurement, resulting from unevenness of liquid application caused by surface tension effect in the liquid supply head. The DSA is applicable also to nonaqueous or viscous liquids as test liquids.
