# How much photo emulsion



## DAFOWL1 (Nov 8, 2008)

Ok I am trying to learn how to silk screen I brought a speedball kit. I also brought a couple of extra screens. My question is when ever I remove the emulsion to show my image the lines are not crisp. I dont have a pressure washer just yet. Im washing out in the shower. Am I not using enough Emulsion or is there something else going on. Please help. Thank you in advance


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## torodesigns (Jun 24, 2007)

There could be several things . . . there is not proper contact of the art with the screen . . . exposure times may be to long to short . . . also you can try to sprinkle a little water over the screen to loosen the emulsion wait a couple of minutes then wash out the screen. 

To many variables. . . to pinpoint to one.


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## DAFOWL1 (Nov 8, 2008)

Thanks for your response Im going to keep at it till I get it right


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## torodesigns (Jun 24, 2007)

One thing that you want to do is create a step burn test and just go at it.


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## allancaps (Jan 5, 2009)

torodesigns said:


> One thing that you want to do is create a step burn test and just go at it.


Hi sir toro, how do you go about this step burn test? I heard it's a good technique to make the trial and error way of exposure. Would you be so kind to walk us through the process?

Thank you sir! Help is very much appreciated.


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## Tj Ryonet Tech (Jul 28, 2008)

*Exposure Time / Step-Wedge Test:*

Like anything else in life screen printing is a pragmatic series of events, you must look at it in each stage and determine the problem. After looking at the entire series of events you’ll find that art, screen, printing and troubleshooting will fall effortlessly in place. 
Concerning the problem of exposure and washout let’s break it down into events;

1. You created the art, output the film and had a screen coated.

2. You exposed the screen, attempted to wash out with no results.

Since you’re early in the pre-press stages the answers to your problem are obvious and easy to repair, don’t worry that you didn’t recognize them as even the most seasoned printers overlook minor details.

The troubleshooting begins at you’re art;

Was the positive opaque enough? (Could you see light through the film?)
_ 
If light is creeping through the black images of your film it’s NOT dark enough and will expose as the rest of the screen would, only slower._

How long has your screen been sitting and has it been exposed to any light before burning?

Screens that have been exposed OR subjected to excessive heat during drying will expose. I’ve had screens ruined and exposed by keeping my screen box temperature too high. Screens that have been sitting over a couple of weeks and having the door opened and closed will pre-expose as well.

Is your exposure time long enough?
_ 
Over time light sources weaken, especially HUV (Black light) units and to compensate you increase your exposure time but make sure your positive is OPAQUE!_

If your unsure of an exposure time perform a “Step-Wedge” test, this involves dividing your screen into 4 sections and marking each with a specific exposure starting with the manufacturers then increasing in increments of 2 minutes per section.










Mark the screen and at the top of each section write 4 minutes, 6, 8 and 10. Produce a piece of art with type, shapes and even some halftones and place it in the 4 minute section, cover the remaining 3 sections with the black sheet; expose for 4 minutes.










After the initial exposure move your art and sheet to the next section, covering the 4 minute section with a light safe sheet as well, you only want the 6 minute section exposed to your light source. Expose this section for 6 minutes and follow this procedure until ALL 4 sections have been exposed at the times indicated.










Wash out the screen as you normally would, completely wetting both sides the let it sit for a few minutes allowing the emulsion to soften (your washout room should be yellow lit as well) then spray softly again on both sides until you see your image washing out.

*IMPORTANT;* Always do your final washout from the SHIRT side of the screen as this is the side exposed. To determine the best exposure look for; edge definition and degree of unexposed emulsion on the squeegee side while washing out. A properly exposed screen will have less slime on the inside as the exposure light has burned 75 to 90% of the emulsion. Be aware on finer detail you may want to cut back time to maintain the details.

After you have gone through all these parameters, found your time, washed, dried and blocked out your screen and ready to tape don’t forget to post-harden your screen for strength and longevity. This is nothing more than exposing the screen on the unit for 10 to 15 minutes or setting it in the sun for 5 minutes, why? During your initial exposure your only trying to burn the image on a screen and maintain detail, post-hardening will ensure a strong, long lasting screen.


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## torodesigns (Jun 24, 2007)

This is exactly how I would of described it but TJ is more detailed and to the point. This will save you headaches in the long run. Let us know how it goes.


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## allancaps (Jan 5, 2009)

Thank you sirs, but I still have a little problem regarding the steps, although you have been detailed enough for me to get the basic idea, but still, would this process work using exposure under the sun? some of the threads here said that it can be done, although many factors should be considered. I have been trying (frustratingly) to expose using the sun, but it becomes more of a trial and ERRORS rather than getting and learning what i should be getting out of it. Any other suggestions? Thanks in advance!


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## torodesigns (Jun 24, 2007)

That I don't know I have look into this. . . I know when I burned in the sun it only took me 45 - 60 seconds. I will call a guy near me and i will ask how he honed in the process.


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## allancaps (Jan 5, 2009)

torodesigns said:


> That I don't know I have look into this. . . I know when I burned in the sun it only took me 45 - 60 seconds. I will call a guy near me and i will ask how he honed in the process.


That would be a big help... You know, here in the Philippines, we try to make do with what's free and available, and apparently, the sun is free and pretty much always available ! I'm doing this for a hobby so I guess I would follow the other threads when they said that I might consider investing when I really get the hang of this. But for now, I can make do. Thanks again!

Oh, btw, this is supposed to be another topic, but i would like to ask it anyway, is it advisable to make my own screens? i don't have a screen stretcher so i guess the tension would be an issue... if so, how can i get a good stretch to my screens?


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## moosehansen (Jul 24, 2008)

Hello everyone, I too am at the beginning stage, I have built myself the perfect shop for silkscreening, but having a problem with the process after I coat the screen with Diazo Photo Emulsion which I bought in a set, after I burn the screen with the light bulb 60w halogena at 24" away for 15minutes the emulsion washes out and doesn't leave any of the wording but a complete clean screen as if I hadn't had anything, am I not burning enough? is the bulb wrong? or could the emulsion old?
*HELP!*


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## allancaps (Jan 5, 2009)

moosehansen said:


> Hello everyone, I too am at the beginning stage, I have built myself the perfect shop for silkscreening, but having a problem with the process after I coat the screen with Diazo Photo Emulsion which I bought in a set, after I burn the screen with the light bulb 60w halogena at 24" away for 15minutes the emulsion washes out and doesn't leave any of the wording but a complete clean screen as if I hadn't had anything, am I not burning enough? is the bulb wrong? or could the emulsion old?
> *HELP!*


Had a similar prob when I started. Everything just washed off. Did you mix the emulsion with the Sensitizer that came with it? In my case, I thought the emulsion was enough, until I read here that I had to mix it with the sensitizer (I bought them separately ) then coat my screen; haven't perfected the exposure up until now though...  that's because I'm still exposing under the sun...  Hope this answers a part of the question...


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## moosehansen (Jul 24, 2008)

Yes I mixed the two, but I wounder if the set was old, I'm going to a commercial outlet wharehouse company that sells only to silkscreen professions, I believe that is to be the problem.
Where I live it is foggy a lot of the time, direct sun light can be rare and I have a 1,000 sq ft shop under my house, so I'm not going to give up, 
thanks for your input, this site is so helpful


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## Tj Ryonet Tech (Jul 28, 2008)

Usually for basic exposure set up I would recommend a 500W bulb at about 16 inches from the screen exposing for 12 minutes. If everything is washing out and you are only using a 60W bulb you are underexposed. You need to increase the strength of your bulb. You can find a 500W bulb at a Home Depot, etc. Be sure to remove the glass covering the bulb because it has a UV protectorant on it.


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## DAFOWL1 (Nov 8, 2008)

I think a 60w bulb is not strong enought. I use a 120w bulb. My Problem was I was exposing the screen too long. I would expose for 1hr at around 12 inches now I only leave in under for 20 mins to a half at it works out perfect.


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## Patrioteesm (Jan 30, 2010)

i dont know if this would be the right forum/thread to post this but in a 1Kg pre-mixed photo emulsion (tulco), how many 17 x 19 inch frames can u fully cover? 1 side, two coats. tia


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