|HOME| |DIY FAQ| |GEO FAQ| |Debugging Page| |Links| |Schematics| |Wiki| |Layouts Gallery| |STORE|
|AMPAGE| |GEOFEX| |AMZ|

Welcome, Guest. Please login or register.
Did you miss your activation email?
November 23, 2014, 01:49:14 PM
975210 Posts in 103858 Topics by 33228 Members
Latest Member: The Ballzz
Home Help Login Register
DIYstompboxes.com  |  DIY Stompboxes  |  Building your own stompbox  |  Screen Printing int dark 0 Members and 1 Guest are viewing this topic. « previous next »
Pages: [1] Go Down Print
Author Topic: Screen Printing int dark  (Read 1310 times)
jonse
Posts: 23


Screen Printing int dark
« on: December 16, 2007, 08:49:10 AM »

I understand that the emulsion used in creating a screen is light sensitive and should be used in the dark. However I recall reading somewhere that you can use some colored light bulb like yellow or blue or some something. I can't seem to find this info. does anyone know which color is safe?
Logged
R.G.
more
Posts: 16298


WWW
Re: Screen Printing int dark
« Reply #1 on: December 16, 2007, 08:59:23 AM »

Screen printing emulsion is quite sensitive to UV and blue light. The lower the light energy, the lower the effect on the emulsion. However, it is much less sensitive than photographic emulsions.

It is common in wet-process photography (or was, back when that existed) to do a test exposure. You set up a test lamp, and a sensitive surface. You cover the sensitive surface, turn on the test lamp, and uncover the sensitive surface a little bit more at time intervals. Then you process the sensitive surface and you will see shades of exposure corresponding to the amount of light it got. This tells you how long you can work under that lamp before exposing things.

That being said, screen printing emulsion is dramatically less sensitive than photo emulsion. The standard exposure for screen emulsion is to give it something like 15 minutes in front of a high intensity arc-lamp. I suspect that a 60W incandescent bulb would not affect it for long periods of time. Just be sure to dry the coated screens in the full dark.

Even better, read the instructions on your emulsion can.   Smiley
Logged

R.G.

Every single NASA manned mission starting with the Gemini series has carried a roll of duck tape.
Yes, really. Look it up.
jonse
Posts: 23


Re: Screen Printing int dark
« Reply #2 on: December 16, 2007, 09:36:10 AM »

Actually there is nothing written on the bottle of emulsion that came in the Speedball kit, and the instructions are not specific on this detail. From you suggestion I guess a very dim light in the far corner of the room shouldn't have an adverse effect. Just enough light to see what I am doing.
Logged
R.G.
more
Posts: 16298


WWW
Re: Screen Printing int dark
« Reply #3 on: December 16, 2007, 10:56:22 AM »

I found the Speedball kit instructions on line here:
Quote

While it doesn't say what the maximum light is to NOT expose the stuff, it does say what the minimum time needed for proper exposure is 1 hour 32 minutes with a 150 W clear incandescent bulb 17 inches away from the dried screen. Light intensity is an inverse-cube relationship, so if you have a 100W incandescent bulb many times further away, exposure time should go up hugely, so one light bulb on the ceiling should be fine for hours, I'd guess.
Logged

R.G.

Every single NASA manned mission starting with the Gemini series has carried a roll of duck tape.
Yes, really. Look it up.
jonse
Posts: 23


Re: Screen Printing int dark
« Reply #4 on: December 16, 2007, 11:11:32 AM »

Thanks R.G.
This is my first time attempting screen printing, and I'm a little weary of ruining it and having to start all over. But I guess that's the best way to learn.

Paul
Logged
John Lyons
Posts: 5763


Basic Audio


WWW
Re: Screen Printing int dark
« Reply #5 on: December 16, 2007, 05:04:13 PM »

Paul
The speedball emulsions are fine to work with in normal room lighting.
You only need 10 minutes or less to coat the screen and get it done.
When you finish making the screen then put it in a dark place to dry. A fan helps this go faster.

The lits usually come with two bottles, an emulsion and a sensitizer which may be liquid or a powder.
The instructions are crucial and so is a test run. It really depends on your set up and how you expose the image.

John

Logged

Basic Audio Pedals
www.basicaudio.net/
The Tone God
Global Moderator
Posts: 5299


Maggie


WWW
Re: Screen Printing int dark
« Reply #6 on: December 16, 2007, 06:36:36 PM »

The inks those Speedball kits come with are not very good for enclosures in my experience. They are intended for things like cloth, i.e. T-shirts. Some inks are for paper too.

For enclosures you might want to look into enamel inks but handling those inks adds a new degree of complexity.

Andrew
Logged
jonse
Posts: 23


Re: Screen Printing int dark
« Reply #7 on: December 16, 2007, 08:56:24 PM »

The inks those Speedball kits come with are not very good for enclosures in my experience. They are intended for things like cloth, i.e. T-shirts. Some inks are for paper too.

For enclosures you might want to look into enamel inks but handling those inks adds a new degree of complexity.

Andrew

Yeah, I picked up a jar of acrylic paint as well. I'm not sure if it will do. I'm going to try it on a test enclosure first. If it doesn't work I guess I'll have to find some Nazdar paint specifically for preprinted metal.

Paul
Logged
The Tone God
Global Moderator
Posts: 5299


Maggie


WWW
Re: Screen Printing int dark
« Reply #8 on: December 16, 2007, 10:52:18 PM »

Yeah, I picked up a jar of acrylic paint as well. I'm not sure if it will do. I'm going to try it on a test enclosure first. If it doesn't work I guess I'll have to find some Nazdar paint specifically for preprinted metal.

I tried the acrylic ink as well along with various additives. No dice. I think you will have to find an enamel ink like Nazdar. IIRC there have been some people around here who have used enamel inks with decent success. I never got around to trying out enamel ink with the Speedball kit so I cannot comment further on that aspect.

Andrew
Logged
Pages: [1] Go Up Print 
« previous next »
Jump to: