We got some photos from a shirt company that had a printer reporting that the shirts looked like crap after washing. From what I see, the ink is not cured, and I told them what the causes might be. (Here's an example of undercuring – the print on the left looks fine, but after washing it looks muddy and cracked.) Undercuring can be from:
- Shirts did not spend enough time in the dryer.
- Shirts that are colder than normal. (If you normally send shirts through when it's 70 degrees Farenheit with the dryer set at 350 degrees and they cure, and then you send them through when its 40 degrees on a cold fall morning, they may not cure
- Thicker ink deposit. (The ink has to cure all the way through.)
- The dryer temperature may be fluctuating or not high enough.
- The shirts can be damp even if you can't tell by touching them. This happens with thick shirts or canvas most often. The moisture then evaporates in the dryer and that cools the shirt and this causes the ink to not cure.
- Too much of certain additives to the ink. This seems to happen when somebody puts something in the ink and doesn't label it and someone else comes along and uses it like it is straight out of the bucket.
- While rare, I have seen a shop that has the doors open and the breezes disrupt the dryer.
- All inks are not the same – one may cure at one temperature and another may not
- Certain fabrics reflect or absorb the heat in the dryer and you have to adjust your time and temperature accordingly; it's the same with certain inks, particularly metallics or reflective inks.
You can stretch the shirt, probe your dryer or any number of other methods to check for cure, but nothing works like putting it in the washing machine and seeing if the ink sticks on there. – RR
A Little Transparency
I love simple-yet-effective printing techniques. Overprinting semi-opaque inks creates a level of transparency which reveals a percentage of the underlying color. It's simple, but not as easy as it seems. A surprising amount of consideration went in to determining print order, flash positions, ink formulations, etc., to pull off the effect on this shirt. – TD