- Hot, humid summer weather requires special precautions before shooting screens.
The full version:
As summer finally arrives in Canada you need to remember to take extra measures to dry your coated screens and then keep them dry. This is particularly applicable if you are in one of the regions of Canada where the humidity rises sharply in summer.
The first item you need is a hygrometer. It will allow you to monitor the humidity in the coated screen storage area which should not be allowed to rise above 40% relative humidity. Why? Because dry emulsion-coated screens are susceptible to re-hydration. And why is that bad? Because if you shoot damp or re-hydrated screens, you will end up with the same effect as underexposed screens. Screens are only resistant to humidity after exposure.
You cannot underestimate the potential hassles if you do not dry screens properly after coating or if you allow them to re-hydrate before shooting. Pinholes, stencil breakdown, reclaiming difficulties, and ghosting after reclaiming are all possible. And who needs those additional problems slowing down production in the busy summer season?
So how to keep the screen storage area at below 40% relative humidity during the humid summer months? Dehumidifiers, exhaust vents and air conditioning can all help depending upon the circumstances in your shop. In most cases though, a dehumidifier should do the job. To be sure that a screen is suitably dry before exposure, a moisture meter can be very useful too.