One topic that we encounter on a daily basis is the importance of a light sensitive environment to work in. It is recommended that you find a space to work in with low lighting. Try to eliminate any UV light from entering the room, such as through windows, or from unfiltered light bulbs.
Once you have put together a dark room of sorts you may consider working under a yellow light, this will eliminate the UV rays and provide you a safe area to prepare screens. UV safe yellow and red bulbs can be purchased at most hardware stores.
Once the screens are coated you now have an active photographic screen! Think of it like its film in your camera. If you pulled the film out of the camera it would be exposed and your pictures would be lost forever!
Most likely you have received a quart or gallon of emulsion. Ensure that the emulsion matches what you are trying to do. If you are printing waterbase, you will want a water resistant emulsion such as our WBP Dual Cure emulsion. If you are just printing plastisol, our RXP Dual Cure will be perfect! For any graphic or sign work, you will want a solvent resistant emulsion, such as our SVP Hybrid emulsion.
Typically all emulsions do the same thing. They provide a smooth layer that attaches or embeds into strands of the mesh, making the screen very tough and durable once it is exposed!
DUAL CURE DIAZO
What kind of emulsions are on the market? Several kinds! One of which is the dual cure diazo, this emulsion is a two part system. Part one is the diazo, that is the part that is a photo sensitizer that is mixed into part two, which is the emulsion. To activate the emulsion you must mix water into the small container with the diazo, put the cap on and shake it up, pour the contents into the emulsion and stir it up, then let it stand for about 2 hours. At this point the emulsion will be usable!
For general T-shirts, hoodies and fabric based substrates, we recommend using a dual diazo emulsion because of the wide latitude for exposure times. What does that mean?
Most people who purchase our kits will find out that we offer a selection of light sources to expose screens, if you use a 500 watt halogen and some one else uses exposure unit light box the exposure times will vary, so will your results! So by using a dual diazo emulsion the exposure times dont have to be timed down to the second. Times are not as critical.
PRE-SENSITIZED PHOTOPOLYMER EMULSIONS
Pre-sensitized emulsions are ready to go right out of the gate. Typically these emulsions will expose much faster than the dual diazo emulsions. Screens can be coated a little thicker and its best to expose with a stronger light source and a shorter duration! These emulsions have more solids built into the mixture that will provide more body and will be thicker. These kinds of emulsions are intended for extended runs and are very tough!
When doing signs you will need an emulsion that will stand up the harsh solvents and cleaners used in those processes! They are offered as dual diazo and presensatized formats however they are much tougher and can withstand washout with chemicals or water which may otherwise cause the screen to breakdown prematurely!