The introduction of moisture into the sublimation process can cause unwanted results. During production with a heat press operating at 400 degrees, that moisture can flash to steam and literally blow away the ink from its intended target. Some of the problems that are attributed to moisture include: color shifting (colors lose accuracy), bleeding of the image, and uneven transfer of solid filled areas.
Under normal circumstances, a small amount of moisture can accumulate in your transfer paper and it’s usually absorbed directly into the substrate during heat pressing. However, hard substrates like metal and ceramic are unable to absorb excess moisture. Thus, it’s important that you take steps to minimize the introduction of moisture into the process.
The first step is to protect the sublimation paper from moisture absorption. As a preventative measure, you should store your paper in dry place. Avoid using Zip-Top plastic bags as they can actually trap moisture within.If you suspect moisture, set the paper on your press for a few seconds. Do not press it. Just expose it to the warmth. The heat radiating from the press should help evaporate most of the moisture.
Another trick is to use newsprint or butcher paper instead of a Teflon sheet. The paper will help absorb moisture from the transfer sheet during pressing (Teflon will not). Be sure to use a fresh sheet of paper on each pressing.
If you are working with garments or fabric, it’s also possible that the substrate may contain a bit of moisture. Pre-pressing the garment for about 3 seconds, should remove the moisture and any wrinkles as well. Do not overheat the substrate! Applying a sublimated transfer to a hot surface will start the gassing process prematurely, which may lead to ghosting.
In addition, you should focus on your work environment. If there is a high level of humidity present, it may be contributing to the moisture issues. A de-humidifier may be necessary to help control humidity issues. However, reducing it too much can have negative effects on the inks and your equipment. Thus, you should invest in a hygrometer and take some readings. The ideal operating conditions for sublimation are 70– 80℉ with 35% - 65% relative humidity (no condensation).