You got a Moire pattern in your film, it looks like you have a problem with your original artwork, did you output your film from a printed design?
Challenger
I actually didn't use any postscript software to print this, just photoshop and tweaked settings.
proper film density is essential to a good positive. without a postscript driver and RIP you suffer from a poor ink deposit. make sure your printer settings are sufficient.
did you use photoshop's color halftone feature on a greyscale picture with a 4px max radius? on a rather large image?
how do you measure the size of your halftone dots? those look huge, though perhaps you've a filter on the image and a smaller dot structure underneath that i can't see.
a 305 is superfine mesh and can easily hold halftones at 55 lpi.
it could, theoretically, hold the dot pattern i see in your image, but is certainly overkill and could be causing problems in the exposure/ washout process. i'd suggest you try an exposure step test on the 305 screens to ensure proper exposure.
edit: with an r1800 be sure you select "premium photo paper glossy" and "best photo" in the print options section.
Generally speaking, an inkjet printer does not include postscript, and even if it did, it doesn't mean that the "Rip" will print halftone dots. The postscript interpreter of your epson is only used for color calibration, it doesn't include a halftone output, so you need a Rip or a driver aplication that is able to take your artwork and create the correct postscript data to generate a raster for the entire image, and then manage the spooling of the raster data to the printer.
Moire are undesirable patterns that are created when two or more repeating frecuencies halftones, screen tints, screen mesh, etc. interfere or interact with each other, in this case as the one you got in your film. As I can see, you are only printing one color, that is why I asked you if you are outputing your film from an original that is already printed, because this can cause the moire you got in your film, also you can get it if your original artwork is a low-res downloaded from the internet. If the original is not the problem, then your printer settings are wrong and without a Rip or a driver aplication you just won't be able to print halftone dots. At this moment I'm not worry about your exposure, you already got a problem before you burn you screen, You won't be able to burn and develop a good screen with a bad film positive, please analize your screen and the printed sample there are not highlights, no quarter tones, no midtones, only some deep shadows, which means your film is not good enough to burn a screen, so you need to find out where is the problem comming from.
Hope this can help you
Challenger
Thanks for all of the input and help guys, really appreciate it.
Ok one thing that might be the problem that I just realized is when I washed the emulsion off of the screen it wasn't a pressure washer, rather a house. Could this have not been enough to wash all the emulsion out?
Do you have a vacuum blanket for your exposure unit? If not that's going to be your problem. Without a vacuum blanket your ability to burn halftones is greatly diminished. The first time I did a 4 color process print areas were completely lost and faded. I know I was losing the 10% and less halftones without a vacuum blanket but doing the process proved I was losing a whole lot more than 10%.
Needless to say that's when I got a vacuum unit. Screens burn great.
HELP!! what did I do wrong??(pics) 
