How to Troubleshoot Screen Printing Exposure
- 1). Check the expiration date of the photo emulsion. Emulsion does not have an indefinite shelf life, and a can of emulsion that has been opened will deteriorate after a few months.
- 2). Check to make sure that the emulsion is applied to your screen in an even layer. If the emulsion is thicker in some areas rather than others, you will lose a lot of detail in parts of your image when your rinse it.
- 3). Make sure there is no light in the room where the screen is stored during the emulsion drying process. If even a small amount of light falls on the screen while it dries, then the screen will react. If you have to go into the room at any point, use a nightlight as a guide. Be sure to turn it off when you leave.
- 4). Check the lighting you are using when you burn your design onto the screen. Higher wattage light bulbs will require less exposure time than lower watt ones. Consult an online time table like the one at Speedball (see Resources) for an accurate time estimate.
- 5). Adjust the distance between the screen and the light bulb. A light that is several feet away from the screen will require more exposure time than a bulb that is closer to it. Again, consult a time table. Also make sure that the light is suspended directly over the screen and does not shine on it from an angle.
- 6). Make sure you are using an incandescent light rather than a fluorescent one. Most exposure tables are intended for incandescent bulbs. Fluorescent bulbs shine more brightly while using fewer watts, therefore most exposure tables do not apply to them.
- 7). Adjust your washing technique when you rinse the unexposed emulsion of the screen. Rub the screen with gloved fingers, but do so gently. If you rub too hard you will wear away at even the exposed emulsion. Also make sure to wash the screen in a low-light environment or you will accidentally expose areas of your screen that you wish to wash away.
- 8). Use the sun as a light source if all else fails. Use a black cloth to cover your screen while you transport it outside. Expose the screen for 15 seconds on a sunny day or 18 to 20 seconds on a cloudy day.
