# Exposure times



## bjparker (Apr 14, 2010)

Hello, 
I am using an exposure unit with 6 unfiltered 20w black lights. And i am using Ryonet's SVP Hybrid/photopolymer emulsion. I cant seem to get my exposure times quite right for some images im trying to burn.

Big block letters or anything really dark i can do in like 2-3 minutes, spray it out, no problem. But images with fine detail, i cant seem to find the right time, i either over expose to where i have to use the hose too long and nothing will wash out, or i under expose it and end up washing it out and causing the image to break and melt away. 

is anybody using this kind of emulsion with a similar light source? What are your exposure times? what am i doing wrong?


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## fullofglory (Oct 12, 2011)

I'm about to use the same emulsion today for the first time and I have the same exposuexposures unit as yours I don't have any info to offer you from experience I was acutally looking for exposure times myself because I don't have time to do a step wedge test for this job I'm doing. But you could peform a step wedge test and if done correctly you won't have any problems exposing after that.


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## bjparker (Apr 14, 2010)

I've found right around 5 or 6 for thick black images is just about right. But still can't quite get the fine fine details. What's your mesh count? Let me know what you come up with plz!


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## CCClothing (Apr 1, 2011)

bjparker said:


> Hello,
> I am using an exposure unit with 6 unfiltered 20w black lights. And i am using Ryonet's SVP Hybrid/photopolymer emulsion. I cant seem to get my exposure times quite right for some images im trying to burn.
> 
> Big block letters or anything really dark i can do in like 2-3 minutes, spray it out, no problem. But images with fine detail, i cant seem to find the right time, i either over expose to where i have to use the hose too long and nothing will wash out, or i under expose it and end up washing it out and causing the image to break and melt away.
> ...


Alright, so I can add something to this since I am using the exact same emulsion and let me tell you, this stuff isn't very flexible with exposure times etc. I am actually using Ryonets Exposure Box so we have the same set up here! I also use the hose for now with a pressure attachment and have the same exact problems!..dude are you me? 

I have learned a few things with this emulsion.

1) Drying. It seems that this emulsion doesn't enjoy drying. I have another dehumidifier coming today that I am going to throw in my dry box to help out, but on it's own in Southern California, this emulsion simply takes 48-72 hours for a complete dry. 

2) Exposure times must be almost on the dot. If they off at all, problems can easily be seen. My exposure times for a semi-detailed image is exactly 1:30. Let me tell you that I seriously was off 5 seconds up or down, the image is done for. 

3) Why in the world did I buy this with my current set up. Talking with Ryonet staff about this emulsion it appears that only full on shops use this emulsion (highly skilled people?) with vacuum exposure etc. 

4) It's blue it bothers me. But that is my opinion.

I will be switching back to Diazo next time I need new emulsion. 


However, in regards to your washing out and "melting" off problems I think I discovered why and it might be different for you.

The first time I ever used this emulsion, everything went great. It dried with no problems, and it washed out with ease..the second time..my image actually broke down with very minimal wash out and the emulsion just peeled right off. Problem? Drying. The emulsion wasn't 100% dry. It was still tacky in small areas of the screen. I would say that if you have any amount of tackiness on your screen, do not attempt it. 

Do you experience drying time problems as well?


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## fullofglory (Oct 12, 2011)

My exposure unit has 8 bulbs instead of 6 and is is unfiltered 15watts 20x24 aluminum casing bought from Ryonet.

just exposed two screens the first was a 230 or a 280 and the other was a 156. 

the first screen I exposed for around 1min 20 secs it was just a bit over exposed and I lost the image at the end of the washout.

The second screen I exposed for about 60secs it was a little better than the first the image but it did wash out but it was still a little over exposed. 

So I'm guessing with my unit exposure time is around 45-50secs this is what I will expose my next screen at I don't change time with screen mesh and so far with all the other emulsions I've used I haven't had a problem.

Again a step wedge test will help you to be more precise with exposure times. I didn't do one because I did not have the time to do so. I attached a link below that will take you through the steps of this process. 

Remember exposing is a process that starts when you print your films are they opaque enough? Is there light entering your dark room? how are you screens stored? How long have they been stored? the article with touch some of these question and help you trouble shoot.

Finding Exposure Times : Ryonet's Help Desk & Screen Print Library


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## bjparker (Apr 14, 2010)

yeah, this emulsion pretty much sucks if you ask me, i swear the other stuff i was using was better, i dont remember what it was, it was a free sample that the seller threw in when i bought my press...but it seemed to be better, though i was still cooking for 4 or 5 min...is that too long? 
Im not sure if my issues are drying issues or not, seems dry after a few min after washout, but maybe not...ill pay closer attention this next time, it was weird because the last image i did (5min) seemed to washout perfectly, but when i printed it looked terrible(melty) so...who knows?
a better question is what SHOULD we be using? what have you had success with? exposure times?


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## CCClothing (Apr 1, 2011)

bjparker said:


> yeah, this emulsion pretty much sucks if you ask me, i swear the other stuff i was using was better, i dont remember what it was, it was a free sample that the seller threw in when i bought my press...but it seemed to be better, though i was still cooking for 4 or 5 min...is that too long?
> Im not sure if my issues are drying issues or not, seems dry after a few min after washout, but maybe not...ill pay closer attention this next time, it was weird because the last image i did (5min) seemed to washout perfectly, but when i printed it looked terrible(melty) so...who knows?
> a better question is what SHOULD we be using? what have you had success with? exposure times?



If you got the kit from Ryonet you for sure were using the Diazo. It's not per-sensitized so you have to mix in the diazo, stir, and let sit for a while in the darkroom before using. I hated having to mix it and let it sit. I just wanted to stir, let sit for a few (smoke break) and coat. But I think I want to go back to the Diazo now lol. I honestly believe it is for high volume shops with top gear. 

With the Diazo two part emulsion, 4 or 5 minutes is just right.

My first print with the Hi-Fi Hybrid Emulsion went smooth and was great. I did a 1/1 coat. Let it dry over night. I exposed for 1:20 seconds (which for some reason no longer works, which is why I am now at 1:30). Washed out no problem and printed. I was using solvents with no hardener and the emulsion ended up breaking down after about an hour of solid printing (that never happened with Diazo two part emulsion)

I am going to be getting my dehumidifier this week and will probably be printing again (hopefully) this weekend. I will take some notes for you and come back to report on my situation since we both have the exact same set up.


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## bjparker (Apr 14, 2010)

CCClothing said:


> I did a 1/1 coat. Let it dry over night. I exposed for 1:20 seconds (which for some reason no longer works, which is why I am now at 1:30)


, 
keep in mind that the longer you use the bulbs, the less bright they become over time, thus making longer exposure times...im going back to the diazo as well, i thought i would avoid stirring too, but i just dont dig the blue...let me know what ya come up with...thx


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## fullofglory (Oct 12, 2011)

I used have used 3 different emulsions, 4 including this one

the first was the DXP pink from ryonet It was okay very forgiving with exposure times. A Ryonet rep even told been this one is recommended for beginners. The only problem I had with ths was it took 5min to expose a screen. 2part

I then moved SP-7500 I bought this from a local supplier here in chicago it's made by murakami it was very similar as the dxp I didn't like it. 2part

I then I tried photocure pro made by the same company as the 7500 I loved it got my exposure times down to about 2min no problems this is what I actually prefer. 2part

Now I'm using this new one we are talking about from ryonet I wanted to test it to see if it worked better. right now with two screens exposed I have good expectations if it continues to perform well I will be using this, if not photocure pro will be my choice for the foreseeable future.

Also, it is recommended that after your screen has dried form washout that you expose it again to to harden the emulsion even more and to ensure you won't get a breakdown on the press creating a longer lasting screen for up to 2,000 prints such as the one you had BJ.


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## fullofglory (Oct 12, 2011)

I figured out how to handle this particular emulsion and I think it might be the same for all one part emulsions. It is extremely light sensitive and any amount of UV light will began to harden the image area instantly. I think this explains why the exposure times are reduced. 

Try replacing all lights in your wash out areas with yellow bug lights you should see excellent result. If you wash out screens outside like I do try switching your time to night. 

I did start to experience the same problems you guys where having and I moved in the house made my basement light safe and the end result was two beautiful detailed halftone screens, the best I have ever seen, I output from separation studio. 

If you guys care to give this a shot let me know the results.


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## Stitches (Oct 2, 2006)

I use Imagemate PC701 emulsion. It is a fast exposing emulsion, reclaims nice and you don't have to be spot on with your exposure times..


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## CCClothing (Apr 1, 2011)

I am going to be coating a couple screens tonight and then printing some stickers on Sunday so I will be sure to take some pics (if I run into any problems) and post them here. 

I do wash out outside but I have a slightly different method from those whom I have talked to who do the same. I actually begin a "pre-wash" inside a bag. 

I burn the screen and have a heavy duty black trash bag on hand and ready with a mason jar of water. Once the screen is ready to be washed out, I simply put it (still in darkroom) in the black trash bag, and pour the water on both sides of the screen to start activating it. I wrap up the top of the bag so no light is coming in from the top and hurry outside where the house (with pressure washer nozzle) is already set to go. I get the hose up and open the top of the bag soaking it..then I pull it out and begin to push to burn out. 

My biggest problem with this emulsion has been drying time and I think my new dehumidifier should solve that problem. We shall see this weekend! Wish me luck dudes!


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## beanie357 (Mar 27, 2011)

We use Qtx.
Fast, holds detail. Exposed right easy wash out, easy reclaim.

We never try a new emulsion without a step test. Orange is reacting pretty much like Qtx.

These work well, but do require the tests to dial in. Suggest you do that before tossing the idea of this type of emulsion. It is a good type.


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## superD70 (Dec 22, 2010)

I do an exposure test on every screen I burn, it doesn't take a second to throw that stoffer strip on there before you expose, then I write down all the variables in a note book, mesh count, color, time, # of coats, humidity. Sure makes it easier to figure out what's goin on when stuff starts goin to hell


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## PositiveDave (Dec 1, 2008)

If you are exposing blocks in 2-3 minutes without problem then your emulsion is fine. You can't expose fine lines because:
http://www.t-shirtforums.com/t-shirt-articles/t108270.html
You might want to optimise your exposure too:
http://www.t-shirtforums.com/t-shirt-articles/t106506.html


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## CCClothing (Apr 1, 2011)

So I coated a screen Friday night around 7PM Pacific Time with the SVP, put it directly into my drying box with my dehumidifier running (had been running for about 3 hours previously to putting screen in the box). I checked it around 9:30PM same night, and it was no longer wet just extreme tack.

I let it sit all day Saturday and didn't check it again until Sunday morning when the screen was still tacky but only in certain areas around the edge of the screen away from the print area. I gave it a few more hours and by 1PM Sunday, it was ready to burn.

The exposure went smoothly. I exposure a fairly detailed image at 1:25 seconds. Following my same method of moving the screen outside I was able to wash out the image with no problems. A few lines within one the top images (multiple images on one screen) didn't get fully blown out but this was my error as I didn't give it enough. 

I let it dry and sat it in the sun for a few minutes.

Other than my error, everything this time went great. I was able to print about 500 stickers and the emulsion didn't show any signs of breaking down during print. 

I have narrowed it down to the simply problem of drying.


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## bjparker (Apr 14, 2010)

awesome! Off thread topic I know, but...how are you doing stickers???


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## CCClothing (Apr 1, 2011)

I do stickers just like you would apparel. Higher mesh count usually (just how I was taught, I have no idea if this makes much of a difference because of the ink etc), rolls of vinyl which I manually cut with a paper cutter to fit the dimensions of the image. 

The image set up is a tad bit different. I learned this process from a company I used to deal with when I was in a band who would just sell you sheets. You would mock up a 11x17 with how ever many images you could fit in that area and he would print you X amount of sheets for a specific price. It was up to you to cut them out. 

So when I prep, I just simply cut out like 100 sheets of 11x17 from my roll and just print on those individually. Using the same tack you would to hold down your apparel to the platen which works just fine. After printing me and my girlfriend just sit down and start cutting out the images.

and the ink is just Gloss Solvent Ink from Inktech or McLogans. It drys in the air so it works great...but this also means you have to print very fast and troubleshoot very fast during the printing process. If it does dry in the screen, not really a big deal, just takes some extra time to stop and clear the image with some remover.

The only issue I have with screen printing stickers is the smell..it will lay you down and I think it's pretty damn dangerous honestly.


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## fullofglory (Oct 12, 2011)

CCClothing said:


> ;1132819
> 
> I do wash out outside but I have a slightly different method from those whom I have talked to who do the same. I actually begin a "pre-wash" inside a bag.
> 
> I burn the screen and have a heavy duty black trash bag on hand and ready with a mason jar of water. Once the screen is ready to be washed out, I simply put it (still in darkroom) in the black trash bag, and pour the water on both sides of the screen to start activating it. I wrap up the top of the bag so no light is coming in from the top and hurry outside where the house (with pressure washer nozzle) is already set to go. I get the hose up and open the top of the bag soaking it..then I pull it out and begin to push to burn out.



Great advice thanks in going to try it out


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## fullofglory (Oct 12, 2011)

CCClothing said:


> ;1132819
> 
> I do wash out outside but I have a slightly different method from those whom I have talked to who do the same. I actually begin a "pre-wash" inside a bag.
> 
> I burn the screen and have a heavy duty black trash bag on hand and ready with a mason jar of water. Once the screen is ready to be washed out, I simply put it (still in darkroom) in the black trash bag, and pour the water on both sides of the screen to start activating it. I wrap up the top of the bag so no light is coming in from the top and hurry outside where the house (with pressure washer nozzle) is already set to go. I get the hose up and open the top of the bag soaking it..then I pull it out and begin to push to burn out.



Great advice thanks in going to try it out


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## CCClothing (Apr 1, 2011)

Let me know how it works for you!


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