I started screen printing back in the spring. Now that the weather has gotten colder, I find that my emulsion is not holding. Like it is underexposed. It is becoming slimmy when I wash out the image. My shop gets cold at night, Below freezing a few nights. How does tempature effect emulsion? Should I dry and maintain the emulsified screens above a certain tempature prior to exposing?
Good question.. I think we all know not to let emulsion in the container to freeze but what about emulsion applied to a screen and dried but not yet burned a image?
I was told I could keep my sensitised emulsion in the fridge to extend it's shelf life before coating the screens. Does this mean I have been misinformed!! I have some in the fridge now and was going to take it out and let it get back to room temp before using, can somebody please confirm of this is okay to do or not? thanks all!!
It is okay, and a good idea, to refrigerate your emulsion so it lasts longer. However, don't let your emulsion freeze. This has happened to me before. I had my emulsion inside of a refrigerator in an uninsulated barn. During the warm months, it worked great, but when the outside temperature dropped, the refrigerator froze it solid. If it gets cold in your shop, it would be best to leave your emulsion out of the refrigerator during the winter. As far as your coated screens, a good solution would be to find a way to put a heater in your drying cabinet. The way I built mine, is that I have a cabinet for holding screens, and an air duct that goes along the back, with holes to blow air over the screens. At the top, incoming air first goes through a filter, then a small ceramic heater, into a blower fan that pushes it through the cabinet, then out through an exhaust fan. This may sound a little complicated, but I built this at my house mostly out of plywood. If anyone is interested in building a drying cabinet, I would recommend this link, it really helped me to understand the concepts of what makes a good drying cabinet:
I feel your pain. We just a month or so ago had to break down and have heat installed in our shop. Nothing was working as usual when it started getting really cold. I have found in this cold weather that it is better (may just be in my head) if I let the exposure unit run for a couple minutes before I put a screen on there to start the exposure process. Good luck.
I used a ceramic heater in my cabinet with a fan as you explained. Worked like a charm. My screens are drying as normal now. I guess with the weather change the humidity was too high and the screens would not dry no matter how long I let them set. Thanks for the help.
Be careful with heating your screens to dry them.....it CAN cause issues with tension.....the best way to "dry" screens is to remove humidity in the air in the drying cabinet...lil heat doesnt hurt but a de-humidifier is the best choice....pull out the moisture to keep the screens consistant....good luck !
__________________ The Shirt Shak-TSS Grafx-TSS Sporting Goods...Gettin it done since 2001
Good point Stuart, also, this can be compensated for by the use of a photocell in your integrator. This allows to you set your exposure by light units instead of time, so even as your bulb gets older, your exposure remains the same.
emulsion problems 
