first off. this is great, just fab.
secondly, i've been screen printing for 2 years, and i've always cut from the green sheet things. could you describe how you burned the image into a transparency with a lightbulb? thanks!
sure thing...coating the screen
i start off with a screen that's at least an inch wider/longer on all sides of the image i want to print (i.e. if i have an image that's 7x9", my screen should be at least 8x10"). then i coat it with the photo emulsion* in a dimly lit area. i use a plastic spoon to scoop the emulsion and pour a line of it on one end of the screen. then i use a squeegee to coat one side of the screen. i repeat this process until the screen is completely and evenly coated. instead of repeating the process for the back of the screen, i just run my squeegee over the other side until the emulsion is even. i've noticed that the amount of emulsion i apply to one side of the screen is usually enough for both sides. drying
when enough emulsion has been applied to the screen, i usually place it in a closet and run a fan to dry the emulsion. without the fan, the drying process takes hours. with the fan, i usually let it run at least one hour just to make sure it's completely dry - if you attempt to burn your image onto a wet screen, the emulsion will wash out when you wash the "stencil" off. the image
as far as the image is concerned, i always create and render whatever design i have in mind in photoshop. basically, the image has to be black and white. not grayscale, but completely black. there are several ways to achieve this result. let me know if you want more details on this part of the process. then the image needs to be printed onto a transparency. the easiest way to take care of this part, unless you do a lot of printing yourself, is to print your image onto regular paper then take it to kinkos and ask them for two transparencies (you want to print the same image twice for darker results by way of layering). then just make two photocopies of your image onto the transparencies. tape them on top of each other - the darker the better, and since it's a transparency, there's always some opacity even with black ink.burning
for burning i use a 200 watt lightbulb inside of a brooder lamp that can handle up to 300 watts. i'ved used a 200 watt lightbulb in a lamp for 150 watts, and that was fine. you can find these lamps at home depot. they come with a clamp, and i believe they're aluminum. my burning process is rather make-shift and kind of amusing. i clamp the lamp to a broomstick and prop the broom stick between two chairs to elevate from the ground. then i place my screen with the dried emulsion on it on top of some books or shoe boxes so that there's about 15 inches of space between the screen and the lamp. you can improvise this part as long as there's that 15 inch gap. it's also very important to cut a piece of black paper or cardstock the size of the screen and place that underneath the screen between whatever the screen is resting on top of. it's also important that the flat side of the screen is on top. this is kind of hard to explain, but basically if you image that the screen is like a box with no lid, the bottom of the box should be facing upward. hope that makes sense. then you position your transparency with the image on top of the screen. the transparency should be reversed so that it appears as the opposite of how you want it to actually look when it's printed. basically, just flip the transparency over. you want to put a piece of glass on top of the transparency, which is sitting on top of your screen. the pressure of the glass will ensure consistency in the printing. your lamp should be centered 15 inches above the screen and then turned on. i usually let it burn for about 35 to 45 minutes, depending on the size of the print. i would say don't let it go for longer than 45 minutes to prevent over-burning. the time factor actually makes a huge difference in the result. washing
when you're done burning, turn the light off and then take off the glass and transparency. you should see a difference between your "stencil" and the rest of the emulsion, which is actually the part that's been burned. the stencil portion of your screen needs to be washed out immediately and not exposed to too much light. i've read a lot of instructions that suggest washing the screen with a hose or something more powerful than your average faucet. what i do is run the bath faucet and wash out as much of the stencil as i can. then i use a toothbrush to scrub out what doesn't wash out, which is usually the finer details of the stencil. i do this to both sides of the screen until the stencil portion of the screen is transparent - in terms of how the screen originally looked. the difference will be obvious. printing
if you want to print as soon as you've washed your screen, you should run the fan on the screen again until it's completely dry. this takes no time at all - usually around 10 minutes or so. i always tape off all four edges of my screen on both sides of the screen with masking tape b/c my emlusion isn't always applied perfectly evenly on those edges. again, if you imagine that your screen is like a box without a lid, place the bottom of the box on top of whatever material you're going to be printing on. if you print a lot, i would recommend creating a hinge-based mechanism for printing. it helps with precision as well as stability. i use a spoon to scoop the ink and apply a thick line of the ink on one edge of the screen, extending the length of the design. then i use my squeegee to run the ink over the stencil, onto the material. the way in which you use the squeegee makes a huge difference in consistency. i think a 45 degree angle works best. and then depending on what type of ink you're using, i would run it over the stencil at least a few times. with some inks, usually light ink on dark material, i'll squeegee my screen 10+ times. with dark inks on light material, i usually just have to squeegee it a few times. i'm always stabilizing my screen with one hand while i squeegee with the other. was this part redundant? it's probably similar to what you're already experienced with.
- the speedball diazo photo screen printing emulsion works fine, and instructions are provided in terms of mixing.
i hope all that made sense. i know there are a lot of good resources already on this forum. this site (http://www.barrysfarm.com/applying_a_photographic_emulsion_to_homemade_silk_screens.html
) is rather helpful as well. just keep in mind that his screens are homemade, which i don't recommend doing unless you print a lot and don't want to reuse screens, or if you're printing something that's larger than a screen you can purchase (i.e. my cat pillow).