Screen E-Book (.PDF) - MacDermid Autotype

3/4 full exposureEFFECTS: Emulsion appears slightly softon squeegee side. Stencil will scum if notwashed out properly. Durability is compromised.Stencil is harder to de-coat.Full exposureExposure time depends on many factors:• Mesh• Stencil (type, thickness)• Lamp (type, distance, age of bulb,reflector design…)Comparing exposure times at differentdistances from the lampAs a general rule the minimum distancebetween the exposure lamp and the vacuumframe should be equal to the diagonalof the area to be exposed. This will ensurefairly even illumination over the exposurearea.Depending upon the exposure area andthe size/power of the lamp, the light intensitywill fall off at the edges of the exposedarea because of the increase in distancebetween the lamp at the centre and theedges of the vacuum frame. This becomesmore critical the nearer the lamp is to thevacuum frame. A test stencil using an AutotypeExposure Calculator will show themaximum area that can be effectively exposedby a given light source.EFFECTS: All the emulsion is fully hardenedand the stencil will provide the optimumresistance and durability.64