Understanding the Role of Humidity in Direct-to-Film Printing
1. Humidity in the room may be too high. We have had a few cases where the environment outside
can cause the inks to not adhere all the way when humidity is 80 % or higher outside.
We do recommend 40 % as the standard, however in some cases of extreme humidity, this can be lowered to 25-30 % to help alleviate the issue of glue not curing properly or excess powder
onto film prints.
What could be happening is that the moisture is being trapped in between the CMYK layer and the glue layer, which causes the powder glue to not stick to the inks enough for the powder to provide a dry seal. So when the image is going into the dryer, the actual ink is not dry enough to have powder
stick to it.
Even though the humidity in the room may be saying it's 40-50%, it could be that the digital readout may be incorrect or not exactly accurate. Try using a dehumidifier to lower the humidity levels down to 25-30 %. This will help you. In most cases we operate in 40-50 % humidity, however, if the humidity outside is extremely high or moist, then changing the inside environment to have less humidity than usual can fix these issues of glue not sticking or drying properly.
2. Make sure powder is sealed and contained. When the powder is exposed to air for an extended period of time without sealing the bag, moisture will build up in the powder itself and cause an issue with laying down and adhering correctly. Its always best to contain the powder in a sealed container, such as Tupper Wear, that has a sealed lid for moisture containment. Also you can purchase a specific container that removes moisture. Please find more information from the 2 links below.
3. When drying it is always best to leave the Plexi-Glass lid on the dryer, do not remove it when drying. This helps to contain the heat inside the dryer for optimal performance and heat containment. This also prevents powder from being pushed out into your environment and onto any loose film. This also allows for the drying process to begin as soon as the print enters the dryer as it rides across
the 1st heating zone.
4. Film can be another typical cause for these types of issues as well. Make sure your film is dry and does not have any excess moisture built up on the surface. Humidifiers can cause this to happen, feel the film for any moisture. Our film has a layer of chemicals that the ink gets imprinted onto.
If the film is wet or slick, the ink will not stick to the film properly.
We suggest that if you see this, to wipe off the film before printing onto it. In most cases the film is off the roll and on the printer deck or dryer openings exposed to the environment during downtimes. This also can be fixed by lowering humidity in the room overnight. Try shutting the humidifier off during the night and turn back on in the morning before trying to print.