Paper formation test

摘要

The visual paper formation control test for a moving translucent web, for use as a photographic base paper or cardboard material, has a light source (5) on one side which delivers flashes of light in illuminating time intervals (tl). The flash time (t1) is set so that, while illuminated, the length of web (1) movement is below the limit where the picture is blurred by movement. The picture is captured by the camera (10) to be displayed on the screen of a VDU monitor, together with a comparative picture. The paper test is pref. for photographic purposes. The web movement, during the light flash illumination time (t1) is equal to or less than 0.5 mm, using a flash time of less than 100 microsecs, and pref. 10-40 microsecs, with a web travel speed of 5-15 m/sec. The picture from the camera and the comparison picture are displayed synoptically on the same screen. The light flow to the camera is polarised or colour filtered.