# Help with exposure time Ulano QTX with 500w Halogen lamp



## papaho (Jul 1, 2011)

So I am attempting to expose Ulano QTX emulsion for the first time with a 500w halogen lamp set up 13 inches away (Ryonet setup) on a 110 mesh screen, about a 16 in x 20 in frame. 

Anyone know the correct exposure time with this unit would be?

Thank you!


----------



## Leadfoot (Sep 10, 2009)

I just made the leap to Ulano QTX so I could try out plastisol. Here is what result I got with my 500w halogen which was a perfect burn for me (solid 7 on the Stouffer step test):

110 mesh screen
QTX coated 1/1
18" above screen
Burned for 12 minutes
At wash out I sprayed it down and let the water soak for about 3 or 4 minutes, washed out very nicely within a minute or so, maybe less.

Not sure why I did 18", looked like a good distance.  I might try it a bit closer next time to see if I can cut some time off of that. At 13" I am assuming you might be able to cut off a minute or two, or maybe even three?

I highly recommend the step test, many here will beat you to death about needing one and boy are they right! It really helps you figure out your set up so you can get consistent burn times.


----------



## tpitman (Jul 30, 2007)

13" is kind of close. You might get good exposure in the middle and less closer to the edges of the frame, but you've got to do exposure tests for all you mesh counts for any particular emulsion.
By the time you've exposed two or three screens guessing, you could've had your time nailed down. And to do a test requires only a small patch of emulsion . . . you don't have to coat the whole screen.
Get a Stouffer test strip and follow the instructions. The best $7 you'll spend, besides on a 6-pack.


----------



## rence12 (Sep 26, 2008)

I'm using 110 mesh , 16 inches away, 1-1 coat ( QTX) 500 watt halogen, ( home made), and I burn between 11- 30 secs to 12 mins and like one of the previous replys I spray the screen let set for about 2 to 3 mins and then spray out , and so far I really haven't had any problems at all ,my screens seem to washout pretty easy within a min or 2, and I've used both trans paper and vellum paper. But since I dont have any kind of rip software , I've been doubling my prints to get them nice and dark, I do use " inkscape though to get a good vector, it's not really a nessecity though, it's just become more of a habit.


----------



## treadhead (Jul 26, 2006)

Same setup at 18" 1/1 and burn for 7 minutes and let soak for a few minutes before washing out. Many times let it go longer...doing something else...but seems ok as well.


----------



## RichardGreaves (Nov 7, 2006)

Hardness, (resistance to dissolving), is the most important step to stencil durability AND reclaim-ability.

Don't guess each time, get a test for stencil hardness - a US$10 Stouffer T-2115 21 Step Transmission Gray Scale. 

A transmission gray scale is a small 5 inch film positive with darker and darker filters next to each other in steps that you should used to monitor every stencil you expose for the rest of your life. You attach it to your stencil on an area that isn't critical to your printing.










This is a standard photographic darkroom test positive that's been used since the 1930's.










When you have one on the stencil as you expose, you'll get a simulation of 21 different exposures to the stencil and you get visual feedback that shows you how well your stencil is exposed.









Printer Information and Training for Screen Printers
Exposure FAQ Screen Making Products how to measure exposure


*Developing T-2115*
When you develop the stencil, areas that didn't get enough exposure will dissolve with water and go down the drain. You want to aim at a Solid Step 7, that doesn't dissolve and go down the drain. More exposure will make your stencil more durable and less exposure will make the stencil less durable.

When you put a gray scale on every screen, you will get visual feedback of the invisible action or cross linking and you will notice when it washes out differently and you will know your lamp or stencil is different and you have to change your exposure duration.


----------

