April 17th, 2018
Jagged, blurry or fuzzy edges on screen prints can render products unsellable. If the edges of your screen prints aren’t clear and crisp, there could be several issues at work. Here are some ways you can prevent rough edges on your screen prints.
Sawtoothing: Eliminating jagged edges
A common screen printing problem, when it comes to rough edges, is sawtoothing. Sawtoothing occurs when the emulsion clings to the grid pattern of the screen, rather than following the straight or smoothly curved lines of the print’s design. The result is that the square grid of the screen mesh comes through; rather than straight or curved lines across the mesh, you end up with a jagged, stair-stepping edge. Some ways you can resolve sawtoothing include:
- Using ahigher mesh count. Your stencil might be sawtoothing because you’ve used too large of a mesh for too intricate of a design. Try using a higher mesh count screen to create a smoother edge for your print.
- Taking care when washing out your stencils.After you cure your emulsion, don’t overwash your screen. Sawtoothing can be caused by spending too much time washing out your screen, causing the more delicate areas where the emulsion has to span an opening in the mesh to wash away. Rinse your screen just enough to clear the emulsion away from the stenciled area.
- Creating a sturdier emulsion.If your emulsion is sawtoothing on your screens, the emulsion isn’t strong enough to hold your stencil. Make sure your emulsion is thick enough by applying at least one layer to both the print and squeegee side, and add an extra layer to the print side. Dry screens horizontally, with the print side down and give your emulsion adequate time to dry. Check your exposure times to make sure your emulsion is curing completely during exposure.
- Using acapillary film instead of liquid emulsion. Creating your stencil with a capillary film instead of a liquid emulsion can help to eliminate sawtoothing because capillary film tends to hold its edges better during washout than liquid emulsion.
Smudged or blurry edges: Creating a clear stencil line
While there is a clear cause of sawtoothing, it can be more difficult to determine the cause of, and resolve, a blurry, smudged or wavy print edge. Some solutions to fix common causes of blurry edges include:
- Increasing yourmesh tension. Loose screen mesh will shift during printing, causing the edges of your images to blur. Increase mesh tension, or swap out your sagging screen for a new one, to improve the crispness of your screen print.
- Using a larger squeegee.Is your squeegee large enough for your image? Your squeegee should extend well beyond the edges of your image. If your squeegee is too small, it will put pressure in the middle of the stencil, rather than distributing it evenly, creating a blurred edge.
- Clearing away ink buildup.During longer press runs, or if you are both pulling and pushing ink, ink can build up along the edges of the stencil and begin to dry. This will cause imperfections in the edge of the stencil. You can resolve this by using a piece of screen tape to clear the debris; just stick the tape to the bottom of the stencil and pull it away to remove the ink.
- Improving your screen-making process.If you’re not creating your stencils the right way, you’ll get blurry or jagged edges. Make sure your film positive is dark enough to block out light during exposure, and make sure the image is flush to the screen during exposure. Check your exposure time so the edges of the stencil don’t wash away during rinse out.
If your screen prints are suffering from jagged, blurry or smeared edges, it might take some troubleshooting to determine the root of the problem and resolve it. Taking the time to find a solution will be well worth your time, however, as clear, clean edges are a necessary for great screen prints.