[Flasher1]

Hola!

I've been reading threads on proper exposure time and
washing out screens,but just when I think I have a great stecil I put it up to the light and Pieces are not washed out and the lines are not crisp.my emolusion keeps blowing out! Using ready mix Emulsion coated 1-1, 110 Mesh
Printing white on black. Exposing on a light box from ryonet, dark fabric on top, youth shirt board and atleast 30lbs of pressure on that, exposing it for 30 sec- 2 ,min.
What the heck am I doing wrong.

 

[selanac]

Did you use a degreaser to clean the screen first?

 

[Flasher1]

I did degrease and let the screens dry for 24 hours in a rack with light safe canvas cover

 

[DogPound71]

How long are you ecpsoing your film. I use emulsion provided from Ryonet called Prochem DXP Pink. I had problems w/ my screen not washing out and I also had jagged lines and misaligned shapes, Mt timing was not the issue it was my film. Do you double your transparency or vellum? I took me 4 tries to get the exposure and washing my screens right. I had density issues. I have a post;

I think 13 minutes on a simple exposure stand is too long, can't wash out entire emulsion. I need HELP!!!!
I hope this will help in some way. Good luck

 

[andimill]

Hey,
Having no idea about your set up, Im going to take a stab in the dark. It's an interesting combination to have areas that are tricky to washout as well as blown out screens. It's true that degreasing the screen could be lending an issue here, but also, it's important to rinse the screen completely after you've scrubbed chemical through it. Left over chemical will be just as bad as grease, and to replace one with the other does little for you.
If there are areas that are not easily washing out, or not washing out at all, it may be that the films you are using are not opaque enough. Can you set your printer to use it's maximum amount of ink/toner?

My suggestion is to try doubling up on your transparencies and also to extend your exposure time. Don't be shy to beef it up to around 5-6 minutes, or perhaps even more if you are not using a powerful UV source. If you have a good opaque transparency, your screen will work out, even if you are over exposing a bit.

Also, I know it can be frustrating when something like that happens, but hopefully you are learning a lot as well.

If you can post any photos of your issues and set up, it's likely someone will be able to source the problem very quickly. It might feel silly to be extremely thorough when you are explaining everything you are doing, but remember this problem exists because there is one tiny thing being overlooked.

-Andrew
Vancouver, BC

 

[InkedApparel]

I think maybe the weight is the problem.......to much weight will bow the glass and cause undercutting.....try less weight to get direct film glass contact.

Inked

 

[out da box]

Dual cure emulsion will give you more lattitude in exposure and more of a chance of success. The pre-mixed photopolymer emulsions are fast, but very tricky to burn high detail and fine lines/halftones unless you're burning under optimal conditions. I still even have issues with photopolymer emulsion not washing out fine halftone dots sometimes.

 

[tpitman]

Letting the screens dry "overnight" might not be enough if you live in a high humidity area, and semi-dry emulsion will give you trouble, too. When I first moved out to my garage, it would take a couple of DAYS for the emulsion to fully dry after coating, and these were in a box with a fan pulling filtered air through it. A dehumidifier fixed that.

 

[out da box]

Good point about the humidity. High moisture will wreck your exposure.

 

[nvstitch]

Have you done a step wedge exposure test? If you dont know the proper exposure time your just washing money down the drain.
What kind of positives are you using? are they dark enough? Is the screen fully exposed?

 

[tpitman]

Have you done a step wedge exposure test? If you dont know the proper exposure time your just washing money down the drain.
What kind of positives are you using? are they dark enough? Is the screen fully exposed?

Exactly, and probably the biggest mistake newbies make is to start with something they read somewhere that may or may not have any bearing on what emulsion, mesh, and light source they are using. Get a Stouffer exposure scale (about $7), read the suggested exposure times from the emulsion manufacturer for the type of light source you have, and start there. The Stouffer exposure scale comes with instructions on how to calculate a much closer "correct" exposure with the next try.