I'm terribly sorry: emulsion is like a plastic transparency type sheet?
The basic screen making process goes like this:
You take a screen. You apply emulsion to it, preferably with a scoop coater (which is basically a small metal trough), but some use other things (paint brush, a squeegee) to save money. Emulsion is liquid and light (UV) sensitive. Once applied to the screen you leave it for a while (completely away from UV) and let it dry. Through all of this you need to keep it away from UV (so yes, this part of the process has a lot in common with darkroom photography). You then put a positive onto the screen - the positive needs to block UV from passing through. Expose the screen to UV. At this point the parts covered by the positive will be dry, but still soft. The parts exposed to UV will have hardened into the screen. Take it away from the UV, remove the positive, and wash the screen. The soft/unexposed parts will wash out. This leaves just hardened emulsion, with a negative image in it. Put ink on the screen, pull a squeegee across it, and you'll apply ink through the areas that used to have unexposed emulsion.
That's a poorly written explanation, but hopefully it makes sense.
For what you want to do, one of the key things to remember is the film positive. The film positive can be
anything that blocks UV from getting to the screen.
Drawing with pen and pencil? Painting with acrylics? This sounds lovely!
Most people are so computer orientated that they'll print film from a computer and never think beyond that.
Since you just need something UV opaque to make a screen, you can do it in any number of ways.
A few things to bear in mind: one screen, one colour. So if you want multiple colours you have to work on multiple sheets of film, putting one colour on each sheet (then one sheet per screen). It can be a nuisance. The fabric length I mentioned was two colour (and about 110cm x 60cm) so doing that was definitely a pain, yet also somehow fun. Satisfying anyway.
There is a specific paint available for creating opaque films. You could quite possibly get away with normal acrylic. Might be worth experimenting with for budget reasons, but there is a specific, reliable product available if necessary.
The biggest drawback: screens are binary. They either print or they don't. You get one colour, no shades of a colour. If I take a brush and paint light opaque paint onto film, you will get a brush stroke, but it'll be high contrast. Areas stay, or drop out.
There is one way around this, but it involves computers / technology (and potentially expense). You can use half-tones to get greyscale effects by turning shades into varying sizes of dots (like CMYK printing, like a photo in a magazine).
I have, for example, drawn a sketch in pencil, scanned it into a computer, printed it on a printer capable of printing halftones, exposed the film, and printed it on a t-shirt using a grey ink. I didn't modify the image during any of that, and you don't need to be computer literate - but you do need access to the technology. The end result looked much like it was drawn on the t-shirt with a graphite pencil.
It's worth bearing in mind that you can pay people to make film, and you can pay people to make screens. For cost reasons you don't want to be doing that all the time, but you can do it occasionally if the design demands it and you don't have the resources to DIY.
Drawing on paper and photocopying the drawing onto film is one of the easiest ways to create a positive.
Another great screen I saw was made using twigs off a tree. The actual plant was taped to film and exposed. It created a beautiful silhouette.
The key principle is whatever part of the emulsion doesn't get hit with UV will print. A lot of people get caught up in computers as the only way to produce work. By not making that mistake, you're opening yourself up to all kinds of possibilities.
While you won't be able to work in
exactly the same way you are used to (printmaking is its own thing after all), you will be able to bring across a lot of your skills, some of the same techniques, etc. It's a new medium to explore, which will be a combination of your old one and some new ideas and challenges.
If you want to reproduce pre-existing works on a t-shirt it would be easier to do it with the aid of a lot of computer technology. But if you want to create whole
new works in a visceral hands on way, there's a world of possibilities.
Then, the exposing process is something like in photography?
Somewhat like it. It's definitely the easiest point of reference for people new to screenprinting.
What would be the cheapest but most effective way (with most consistent results) for me to set up a small operation to screenprint. Low-tech, please!
If it was me, the minimum I'd want to do it properly would be:
A couple of screens.
A couple of different size squeegees.
A scoop coater.
Emulsion.
A safe bulb.
Sheeting to cover windows.
Some film.
An opaque pen or paint.
Waterbased printing ink.
A hairdryer and an iron (can use the same ones as your domestic; they won't get damaged or cross contaminated).
The scoop coater will give you a more even coating of emulsion, which will give you a better print.
To print, you can just use any table. A lot of professionals will tell you you have to use off-contact (space between screen and substrate) to get a good print, but they're wrong. A lot of fabric lengths are printed on-contact. I've printed plenty of t-shirts on contact. Having the wrong off-contact distance or using the wrong ink for on-contact will give you a crappy print, so I think they just assume it can't be done. On contact printing is not only possible, it's easy.
The safe bulb and plastic are to temporarily set up your laundry or bathroom as a darkroom.
To expose the screen, you've got two options. You can either build a cheap exposure unit. That's more reliable, and means you can work at night, but it can be
very slow. And a nuisance to setup. The other option is to use the sun. You'll need to be careful, but sun exposures are a common way to start out in screenprinting. It's a powerful source of UV and it doesn't cost a dime.
The film is what you make your positive on. It would be preferable to buy a pen specific to the purpose, though things like sharpies can sometimes be opaque enough.
The hairdryer isn't a must, but they can be useful to speed up drying. The iron is to cure the ink - it's laborious and sometimes unreliable, but it basically works and it's cheap.
All of the above should cost about $150-300. Less if you can find things secondhand. It'll be enough to create professional prints (if you get the ink curing right

) limited more by your artistic ability and imagination than the materials.