Printing Discharge?

[Logoman]

I am printing my first Discharge job and not working out very well. I am using Ulano 925 WR-P Emulsion, coating 2/2 letting dry and then 2/0 on the print side. I am using a Hix Premier Exposure  Unit (1500 watt metal Halide). Film at 4 min. and the results suck. When I rinse it out it will almost not wash out on the shirt side but on the ink side it is slick like it is not exposed. What am I doing wrong?

[Orion]

You will want a thinner stencil for discharge. Try a 1/1 coat. Also sounds like your film is weak.

[ericheartsu]

that sounds like way to much emulsion. Orion is right 1/1, 2/1 tops! use the sharp side of the scoop coater.

also make sure you have your exposure dialed in, or your screen will start breaking down while printing

[KevWilso]

Your films probably aren't printing dense enough if it is not washing out completely.  Sounds like light is getting through the ink and exposing the emulsion where it shouldn't be.

[Frog]

As the answers suggest, it sounds like a possible combination of too much emulsion, and too little D-Max (and exposure).

Of course, with the emulsion cut back, the other problems may get covered up.

[dirkdiggler]

definitely to much emulsion

[screenprintguy]

I used to use the same emulsion, if you want "925 wr" to work for you, you want to do a 2 over 1 coating, you want to let , "the 925 wr" to be in a room running a de-humidifer for no less that 48 hours. With that exposure unit, you are in no way exposing long enough, especially with film and glass in the unit, you want at least a 10 minute exposure, this will more than likely make you have to double print your film positive to make sure you have a super dense and opaque film positive. This emulsion, you want to let soak in a development tank for a couple minutes after exposure, it's very sensitive after exposure so any pressure water freshly sprayed on it's surface starts your downfall. THis emulsion also needs a long post exposure, preferably in the sun, and then last you will need to spray a hardener on the dryed post exposed screen. Let that dry fully. 925 wr was our go to emulsion for waterbased, and if all these steps are done proper, it will hold up like steel, buuuuuuuuut, skip one step and your done. That's the main reason why I was on a hunt for an emulsion that doesn't need hardners or long post exposing, and fell in love with HXT. It hasssssss to cook long. NOVA from xenon with diazo is also bullet proof, but needs a super long exposure. Aquasol HVP is a lot of people's go to, but you don't have a strong enough exposure unit for it, trust me, been there, done that. Key in any of these emulsions for discharge, w/b printing, is to NOT rush your process. I just wrapped up a job using a discharge base screen that is over a year old, has been used rinsed, racked and re-taped for re-use at least 20 times and is as perfect as the day I shot it. HXT all the way and still hanging in.

[Frog]

I used to use the same emulsion, if you want "925 wr" to work for you, you want to do a 2 over 1 coating, you want to let , "the 925 wr" to be in a room running a de-humidifer for no less that 48 hours. With that exposure unit, you are in no way exposing long enough, especially with film and glass in the unit, you want at least a 10 minute exposure, this will more than likely make you have to double print your film positive to make sure you have a super dense and opaque film positive. This emulsion, you want to let soak in a development tank for a couple minutes after exposure, it's very sensitive after exposure so any pressure water freshly sprayed on it's surface starts your downfall. THis emulsion also needs a long post exposure, preferably in the sun, and then last you will need to spray a hardener on the dryed post exposed screen. Let that dry fully. 925 wr was our go to emulsion for waterbased, and if all these steps are done proper, it will hold up like steel, buuuuuuuuut, skip one step and your done. That's the main reason why I was on a hunt for an emulsion that doesn't need hardners or long post exposing, and fell in love with HXT. It hasssssss to cook long. NOVA from xenon with diazo is also bullet proof, but needs a super long exposure. Aquasol HVP is a lot of people's go to, but you don't have a strong enough exposure unit for it, trust me, been there, done that. Key in any of these emulsions for discharge, w/b printing, is to NOT rush your process. I just wrapped up a job using a discharge base screen that is over a year old, has been used rinsed, racked and re-taped for re-use at least 20 times and is as perfect as the day I shot it. HXT all the way and still hanging in.

I have to call you on this. I do not believe that other than drying, the 925 gets any benefit from sunbathing after development. Diazo emulsions are done cross linking when hit with water and developed. I also used to use this emulsion occasionally back in the day, before I almost exclsively changed to  photopolymers, which, along with dual cures, do benefit from post exposure.

[screenprintguy]

Call it all ya want brotha, but if didn't use that step, "per a ulano rep's recommendation at iss Orlando" we would have break down. I tried it every way we could think, even had Bill Hood write me a long book of an email at how post exposures don't work, buuuuuuut, even the company rep recommended, so we went with it and contrary to some opinions it makes a difference with That emulsion.

[Frog]

well, that's not the first time Bill and I have agreed on something LOL!