You’ve coated a screen for screen printing, exposed it, and rinsed it out. You might notice tiny holes in the screen where there shouldn’t be. Why is this? In this video, Ronald Peters touches on why pinholes and fisheyes happen, and gives tips to stop them before they cause problems on your screen.
WHAT ARE FISHEYES AND PINHOLES?
Fisheyes occur when oils and chemicals are left on your screen after the reclaim process. They appear when oil becomes trapped under the emulsion, separating it from the mesh and leaving small holes on the covered screen. Often, these are the culprit of fingerprints.
Pinholes are little holes that pop up on your exposed screen when dust or lint get on your mesh before coating or from when grime is left on your exposure unit glass. For example, if dust or debris is on your screen when you apply emulsion, pinholes will appear. You can usually detect them by holding the screen up to a light source and looking for light holes.
Everyone sees these mistakes at some point. Instead of stressing about them, use these four easy tips to avoid pinholes and fisheyes, and to fix them when they do occur.
TIP 1: CLEAN YOUR DARKROOM
A clean darkroom is a happy darkroom. Keep your floors, surfaces, and fans dust-free. Ideally, if your darkroom has a lot of traffic or you are in a dusty area, mop and sweep every week. Keeping a darkroom clean is not an easy task. If you’re using your darkroom as a multi-purpose space—a garage, for example—keeping your screens dust-free can be difficult. To minimize dust and debris getting on your screens, purchase or build a screen drying cabinet to contain your screens so they don’t get dusty from the traffic in your darkroom.
For a cheap and easy way to cut down on particles in the air, cut out the mesh on a busted screen and attach it to the back of a fan. That’ll act as your filter. You can also pick up some furnace filters and put them behind your fans.
TIP 2: CLEAN YOUR EXPOSURE UNIT
The glass on your exposure unit will get dirty with use. Fingerprints, dust, dirt, adhesive from tape, all will eventually get the glass dirty. It might not seem like a big deal, but these will block light coming from the exposure unit. All this grime on the glass acts as a mini film positive, exposing pinholes in your screen.
Dusty or dirty glass is the most common reason for pinholes. Clean your glass often. Often, a glass cleaner and a rag will do the trick. If you have leftover emulsion or tape on the screen, use a glass cleaner and the back of a sponge to clean the glass. You can also use an ink cleaner of your choice to soften and degrade any ink, emulsion, or tape adhesive that might still be stuck to your screen. Wipe it off with a paper towel, and you’re good to go! More times than not, you won't see the grime that causes the pinholes until you are done exposing. The cleaner the glass is, the better your screen will be.
TIP 3: DEGREASE YOUR SCREENS
Whether your screens are new or old, degreasing is incredibly important to prevent fisheyes. Degreasing removes any oils, dust, and dirt from the mesh, all of which can cause issues in the adhesion of your emulsion.
You’ll want to have Emulsion Prep, Haze Remover, and Degreaser in your darkroom. Using a degreaser will remove any oils, dust, and dirt from the mesh, all of which can cause issues in the adhesion of your emulsion (like pinholes and fish eyes). Emulsion prep also promotes better adhesion to the mesh, which will help you get a stronger, more durable stencil.
Once you are done with the degrease/dehaze step, do a flood rinse. The water should cascade down the screen with no interruptions. If there is a spot that behaves like oil on water, go back to that spot and degrease again.
TIP 4: USE SOFT OR HARD WATER FILTERS ON YOUR HOSE
Hard or soft water residue can cause adhesion issues with your emulsion, leading to pinholes and other screen issues. Mineral deposits left over on the mesh will wreak havoc with your emulsion durability. You’ll want the water you use to be as clean as possible. Removing minerals found in your tap water is key. Do some research on whether your tap is hard or soft water. Pick up a filter that minimizes hard or soft water chemicals.
HOW TO FIX PINHOLES
Even in the best of shops, you'll eventually get a pinhole or a fisheye. The best way to fix pinholes is to use screen tape or a blockout pen. If you are using water-based inks, try clear nail polish.
Backlight all newly created screens so you can find any defects with the screen before you go into production. This way, you can easily fill in pinholes to fix issues before they show up on your garments.
Pinholes and fisheyes are annoying, and slow down your process. By following these tips, you can minimize pinholes and fisheyes before they turn into a production-stopping problem.