Emulsion step test question...

3729 Views 21 Replies 9 Participants Last post by Hegemone, Jul 31, 2012

ILLustrator78

Discussion Starter · Apr 14, 2012

I actually have two questions for anyone that might have a lot of screenprinting experience,and i really am appreciative of any input or advice i can get.

1.)So i have performed two different step tests and i'm quite confused.The first step test i did was on a 9 by 12 screen with an 8.5 by 11 image and i figured out that the best exposure time was about 6 and a half minutes for the 500w set-up i have.Earlier today i did another test on a 20 by 24 screen with an 11 by 17 image and the best exposure time seemed to be between 18-20 minutes.my question is this..so does exposure time depend primarily on the size of the image your are burning? or could it be that i am doing something completely wrong? i'm perplexed.

second question.

2.) in the washout stage,is it best to wash-out a screen with cold water or with warm water?

i'm just starting out,so any advice is great.

thanks.

1 - 20 of 22 Posts

mustangFWL

· #2 · Apr 14, 2012 (Edited)

Using my 500w light from Ryonet, no matter what size screen, or image, my duel cure emulsion takes 13 minutes exactly to cure perfectly with the light setting directly over head at 18 inches above the screen.

The exposing time depends on your light source, type of emulsion, and distance between screen and light source

As far as the washout goes, I do not think it matters, but I always use the warm setting on my spray shower head, just because, I think it has more pressure vs temperature

selanac

· #3 · Apr 14, 2012

The size has nothing to do with it.

What kind of emulsion do you have, how far is the 500 watt Halogen lamp away from the glass that sits on top of your screen? Is the image opaque, can you see through it?

My 500 Watt Halogen Lamp, sits 12 inches from the 1/4" Low E glass. I removed the Glass from the Halogen Lamp. Did you do that?

It takes me 3 to 3.5 minutes to expose. I than spray water on both sides of the screen and let it sit for 4 minutes. After that I rince with luke warm water using a light pressure washer.

sben763

· #4 · Apr 14, 2012

Question #1 mustangfwl answered with the last line in his post

Question #2 has been a long time debate you will hear both ways I can tell you that I don't even have hot water in my shop and my water comes from a 186' well. So it rarely changes from 56F and I have no issues. I would think warm water may soften the emulsion unnecessarily

ILLustrator78

Discussion Starter · #5 · Apr 14, 2012

selanac said:
The size has nothing to do with it.

What kind of emulsion do you have, how far is the 500 watt Halogen lamp away from the glass that sits on top of your screen? Is the image opaque, can you see through it?

My 500 Watt Halogen Lamp, sits 12 inches from the 1/4" Low E glass. I removed the Glass from the Halogen Lamp. Did you do that?

It takes me 3 to 3.5 minutes to expose. I than spray water on both sides of the screen and let it sit for 4 minutes. After that I rince with luke warm water using a light pressure washer.

Thank you for the reply.

I did not know it was best to remove the glass from the halogen lamp.I went ahead and did that this morning.

The emulsion i have is a HiFi Polymer emulsion that i bought from Ryonet.

Do you have any recommendations for other types of emulsions?

thanks again.

ILLustrator78

Discussion Starter · #6 · Apr 14, 2012

My light source 500w halogen light source is about 18 inches away from each image.I do however have the ability to lower it to about 12 inches.The emulsion i am currently using is a HIFI polymer emulsion that i bought off Ryonet.How does the dual cure emulsion compare to that HIFI emulsion?Any more recommendations are appreciative.Thanks again for the reply.

sben763

· #7 · Apr 14, 2012

ILLustrator78 said:
Thank you for the reply.

I did not know it was best to remove the glass from the halogen lamp.I went ahead and did that this morning.

The emulsion i have is a HiFi Polymer emulsion that i bought from Ryonet.

Do you have any recommendations for other types of emulsions?

thanks again.

If you want the fast exposing polymer try S.E.X from performance screen. I use it and so does Paul but he can give you a better guess on his exposure times as I use a black light unit and I believe Paul uses a halogen. I like it better than the hi-fi I still have 3/4 gal I may give it a second chance but I have been using the other of 2-3 years with great results.

selanac

· #8 · Apr 14, 2012

Did you get the Halogen lamp from Ryonet? Did it come with a stand if you did? The distance from the screen (plate of glass above that with your film stuck between that and the screen) determines the exposure time.

I made mine 12" and it exposes in 3 to 3.5 minutes. To improve the quality, I use a 3/4 inch thick Low-E glass. Home Depot has some really good glass cleaner.

screen260

· #9 · Apr 15, 2012

Were the screens you did the step test on the same mesh count? A higher mesh count takes less time then a low mesh count because there's less emulsion on it.

Reactions: 1

selanac

· #10 · Apr 15, 2012

Oops, that was suppose to be 1/4 inch Low-E glass.

No I didn't step test the Emulsion. I watched a Video from Home Business Network. It's on YouTube now.

She gave the specs.

Tried it with someone else and it worked.

You need to get one worked and practice.

Try block letters to get started.

Reactions: 1

ILLustrator78

Discussion Starter · #11 · Apr 15, 2012

selanac said:
Did you get the Halogen lamp from Ryonet? Did it come with a stand if you did? The distance from the screen (plate of glass above that with your film stuck between that and the screen) determines the exposure time.

I made mine 12" and it exposes in 3 to 3.5 minutes. To improve the quality, I use a 3/4 inch thick Low-E glass. Home Depot has some really good glass cleaner.

Actually i bought the full set-up from this guy that goes by AwesomeArtistLLC.He calls it the GatorPress.

ILLustrator78

Discussion Starter · #12 · Apr 15, 2012

screen260 said:
Were the screens you did the step test on the same mesh count? A higher mesh count takes less time then a low mesh count because there's less emulsion on it.

I think this might be the problem..because the first screen i exposed was just a simple 9 by 12 screen i bought from **** Blick in center city Philadelphia.So i'm unsure what the mesh count is/was.The other screens i bought from Ryonet and they are 20 by 24 screens with a 156 mesh count.I exposed the 20 by 24 screen in 2 minute intervals starting from 4 minutes and went all the way up to 18 minutes..the screen was 18 inches from the film..when i went to wash-out the image the 18 minute part washed out the best..but even at that i still had some emulsion that wasn't coming out all the way..so i'm thinking 20 minutes would have done the trick and left a nice stencil...However,20 minutes seems awfully steep to expose a screen.Especially when i hear of 3-3.5 minute exposure times.

sben763

· #13 · Apr 15, 2012

The 3-3.5 exposure time is with premixed pure photo polymer emulsion. If your using dual cure and a 500w light I've seen 13-20 min exposure time posted but I have never used a halogen and opted from the start for a exposure table.

Reactions: 1

RichardGreaves

· #14 · Apr 15, 2012 (Edited)

ILLustrator78 said:
1) So i have performed two different step tests and i'm quite confused.

The first step test i did was on a 9 by 12 screen with an 8.5 by 11 image and i figured out that the best exposure time was about 6 and a half minutes for the 500w set-up i have.

Earlier today i did another test on a 20 by 24 screen with an 11 by 17 image and the best exposure time seemed to be between 18-20 minutes.

my question is this..so does exposure time depend primarily on the size of the image your are burning? or could it be that i am doing something completely wrong? i'm perplexed.

Lamp distance will effect your exposure. In physics, there's a principle called the Inverse Square Law which says when distance is doubled, the energy is quartered. Sound and electromagnetic radiation like UV and IR energy all follow this law.

With the same coating & mesh & the same lamp, distance change, will change your exposure. Exposure doesn't know how large your image area is. If you didn't change your lamp distance, exposure should be the same.

To measure stencil hardness (resistance to developing or cleanup solvents), I suggest a US$10 Stouffer 21 step gray scale to simulate 21 different exposures. This is a standard photographic darkroom test positive that's been used since the 1930's. It will give you visual feedback and should be on every screen your make for the rest of your life. Ryonet, Nazdar & dozens of photographic distributors sell them. I've got 60 of them in the little box on my desk.

Exposure FAQ Screen Making Products how to measure exposure

ILLustrator78 said:
2) in the washout stage, is it best to wash-out a screen with cold water or with warm water?

Warm water under 100F will encourage water DISSOLVING your unexposed stencil. I don't like using pressure if you don't have to.

Experience how the stencil is supposed to dissolve
To establish a base time for stencil washout, make a very small coating (3 inch by 6 inch?), on a screen and let it dry to the touch - then take it to your washout area and time how long it takes to dissolve. Don't expose it, just wash it out. That is your standard time for washout, for that mesh & coating.

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Reactions: 1

ILLustrator78

Discussion Starter · #15 · May 3, 2012

Great news since the last post.I finally got my exposure times locked in and the stencils wash out like a charm now.I thank everyone for their kind replies and sharing their experiences.It helped a great deal.

Now i have some printing issues to tackle.I am using a heat gun to cure inks.I've done research and read that the best cure temp is somewhere around 320 degrees.Does anyone have any experience using a heat gun?Could you offer some advice/tips? Eventually i'm going to invest in a flash dryer but one day at a time,for now the budget is DIY.

sben763

· #16 · May 3, 2012

heat gun is very inconsistant. There is a quartz heater you can get at most farm type stores under a $100 that you can make a flash dryer. If you need to go heat gun route for now make sure to cure all areas fully

ILLustrator78

Discussion Starter · #17 · May 4, 2012

sben763 said:
heat gun is very inconsistant. There is a quartz heater you can get at most farm type stores under a $100 that you can make a flash dryer. If you need to go heat gun route for now make sure to cure all areas fully

Thanks so much.I appreciate the feedback.I'll have to check into that quartz heater.Do you have a link to one,maybe?

DoItCauseIWant

· #18 · Jul 31, 2012

Please tell what is your exposure time and distance. Are u stil using a 500 watt halogen?

DoItCauseIWant

· #19 · Jul 31, 2012

U can always use your oven on a low broil

ILLustrator78

Discussion Starter · #20 · Jul 31, 2012

DoItCauseIWant said:
Please tell what is your exposure time and distance. Are u stil using a 500 watt halogen?

First i changed emulsions because i read that using the HI-Fi polymer emulsion from Ryonet pretty much requires an exposure unit(which i do not own).The emulsion i am currently using is CCI DXP DUAL CORE EMULSION.Using a 500 watt halogen lamp,I keep the light source about 12 inches from the screen i am exposing.I expose for around 9 minutes and 15-30 seconds.At this distance and time the stencil washes out perfectly every single time with a simple garden hose attachment i bought from lowes for 6 bucks.=)Hope this helps you in some way.

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