Exposure and washout issues

[MaksLightyear]

Hello Castspit Forum members,
Im new to screenprinting and I hope someone can provide some help with exposing and washing out a screen. I actually struggled a bit with a crappy film that i got printed at staples until Jonathan sent me some videos that helped me and I was able to successfully expose and wash out my design although it was actually very hard to wash out. Now my problem is that i found my exposure time with the lesser quality film, but now i have upgraded to a really nice dense thick film positive but i can't seem to dial in my exposure time. I am using basically the same exposure unit as Jonathan did in one of his videos ( https://www.youtube.com/watch?v=kEm5p3K_qoc&app=desktop ) , its a Ranar four bulb UVblacklamp tabletop unit. Except i don't have a vacuum top. In that video he was using the same emulsion( Saati PC blue ) and he exposed for 45 second but he recommended 35-45. With the low quality film that I had, the exposure was at 55 seconds. With the high quality film i have tried pretty much all times in 5 second increments from 15 seconds up to 55 and I'm not really getting anything. Im not really sure how to tell if I'm under-exposing or over-exposing. I actually kind of successfully made one work at 25 seconds but it took so long to wash out and there was more stair stepping or blur than i was comfortable with so I reclaimed it and tried again. I thought this might be do to over-exposure so I tried lowering the exposure time to 20 and 15 seconds. I get the design showing up on the emulsion barely, but it doesn't wash out and using the pressure washer just blows everything out. Now... this next part will will make you mad at me and you will probably tell me to just wash out in a light safe environment but unfortunately I can't really do that because my studio doesn't have any working plumbing so what i do is i wrap my screen in a black bag then run it out to my hose outside. I know you're going to say OMG the sunlight will ruin your exposure just washout in a darkroom but what blows my mind is that i was able to successfully do it before, and with a low quality film, so Im just really confused as to why I can't get it to work with even the nicer one. I hope someone can help.
Thank you

[Catspit Productions]

Okay first of all let me apologize for the late reply. I have been busy launching the new ecommerce site and then this Covid19 stuff happened which distracted me for a while.

It honestly sounds like your film positive is just not right. It's really hard to say what's going on there unless I could see everything you are doing. But if the stencil is difficult to washout usually that indicates a semi exposure. Meaning the film is not as dense as you may think. Basically you should have been able to use the same exposure time for the "poor" film as you would for the "good" film because it would theoretically be more opaque whereas the poor film would be less opaque.

What have you discovered since you made this post?