Top Nine Worst Screen Printing Mistakes

Welcome To Cora’s Corner, where every month I am going to help you with your artwork and screen printing issues.

1. Art problems –

A. Start with good artwork, properly prepared. Don’t use a low resolution jpeg and think you will get a good screen print out of it. The art should be a minimum of 300 dpi at print size.

B. Make sure you can print the design correctly and match it with the correct screen mesh for the artwork.C. If you have a customer, make sure they sign an approval of the final design. You’d hate to reprint a design at your own expense because a word was misspelled!

 2. Screen Exposure problems –

A. The emulsion does not go onto the screen smoothly and evenly.

B. Emulsion is washing out all over the screen.

C. It’s hard to wash out the image on a screen you just burned.

D. Losing fine detail when you burn screens.

E. Pinholes in the screen.

F. The emulsion breaks down while you are screen printing.

G. The screen is hard to reclaim.

 3. Bad registration –

A. Screens can become loose in the bracket on the press if not tightened enough.

B. The platen might be moving if the screw is not tightened enough. Turn it as tight as you can being careful not to strip it.

C. The shirt might be moving if you don’t have enough adhesive on the platen.

 4. Bad ink curing, ink under cured or over cured –

Check the curing temperature with a temperature gun. And know what temperature the ink is supposed to cure at, of course.

 5. Incorrect squeegee angle –

A. Try for a consistent 45 degree angle when applying ink to the screen. Ink goes on pretty smooth at this angle. At an angle of 60-degrees or more, the ink may not get through the mesh correctly and evenly. An angle of 30-degrees or less can make the ink print too heavily onto the fabric.

B. You may need to experiment with the squeegee angle and practice to get it right, see what works for you and keep it consistent. You can also experiment with a “push” print stroke as opposed to the usual “pull” print stroke. There are cases when a push stroke can be useful. But always do one or the other, don’t switch between strokes.

6. Ink spots or smudges on garment or product –

A. Keep the work area and your hands clean.

B. Check the screen carefully for pinholes and fill them with a screen touch-up pen or cover them with a piece of tape.

C. Wash out small spots with a wet shop towel or a spot cleaning gun. If you can’t clean it, keep the shirt and use it for test prints.

7. Design placed incorrectly –

A. Line up you screen carefully. We usually use a t-square to make sure the design is straight.

B. Not all shirts or other garments are sewn correctly or consistently. So you may not be able to use the collar or center crease to position a shirt. Hold out the sides and make sure you are even.

8. Too much ink is getting printed onto the shirt –

A. You may be using too much pressure. Don’t press down too hard on the squeegee and use even pressure all the way across the print.

B. You may have gotten too much ink into the mesh on the back flood. Be careful as you back flood and don’t press down too hard or go over it too many times. If your ink does get too heavy, pull a few prints on test sheets without back flooding to clear out the screen.

C. The ink may be too thinned out

D. You may have an old squeegee with edges that are rounded and need to be sharpened.

9. Too little ink is getting printed onto the shirt –

A. Use a coarser mesh.

B. Make more than one squeegee pass to print. We sometimes do as many as 3, but that is usually the most we need.

C. The screen may be getting clogged. We will rub the underside of the screen with a wet shop towel and then screen a test print or two to try to clear it out. We print on test print squares or misprinted t-shirts and use blank newsprint when test printing for posters and art prints. (Note: We have been told that spraying water mixed with a little bit of dish soap on the underside of the screen before you put any ink on it helps when you print. We mean to try this next time we print.)

D. Try printing on a soft base. We sometimes use a platen covered in neoprene fabric. Especially when we want to print over collars or seams (more on this topic later).

Mistakes will happen, but my best general advice is to work carefully to head off problems before they happen.

Until next month.

Cora Kromer
Cora@qdigitizing.com