Like our skin, plates can be affected by the room temperature, humidity, and age. When humidity levels are low, the plates can look and feel brittle. With the passage of time, the thinner polymer on the plate edges are pulled towards the denser polymer text and images on the front—this causes curling. With a life expectancy of up to 1 year or more, polymer plates do age, but these simple steps can hydrate your plates and give them extra longevity.
Step 1. Place your plate back in your platemaking washout system for up to ½ a minute (or, if you don’t have a washout unit, simply immerse in water). We suggest room temperature for a quick dunking. A ½ minute may only be necessary if your plates are severely curled.
Step 2. Sponge off the water and place back in the drying oven of the platemaker for 5-10 minutes. If you don’t have a platemaker, use a hair dryer to warm the plate and make it more pliable. Placing your plate in a box and blowing the hair dryer into the box will keep the warm air more contained and warm the plates more effectively.
Step 3. After the plate warms and starts to become more pliable, place the plate in its bag and set a heavy object on it to keep the flattened shape.
This should help your plates relax so you can adhere them to your base for additional print runs.
Here’s some final advice:
- if using a hair dryer, take care to avoid putting it too close to the plates.
- be patient, as warming the plates takes time.
- watch that you don’t handle your letterpress plates too roughly after the wash and during drying so your relief images don’t chip.
- remember to store your plates flat out of direct light and in a bag so that fluctuations in humidity don’t affect the polymer.
- check your adhesive backing, to see if the adhesive needs to be re-applied to the back of your polymer plate for a secure hold on your base.