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Protecting Your Image

Posted by Dustin Koch on 10/30/2017

One of the most common issues we have witnessed as a screen printing supplier in the industry is the process of burning images into screens.  Creating a proper image is not a process that you should take lightly for it will greatly define the success and quality of your printing.  Poor decisions in this process can lead to a weak stencil that will not hold up during prints, loss of detail in images, the emulsion getting locked up in the screen, spending a lot of on press time covering pin holes, and many other headaches. Here are some tips that can help!

 

·         Where Do I Wash Out?

It is imperative to wash your image out in an area that will not compromise the integrity of the image! The most ideal way to wash your image out is in a wash out booth with a low pressure nozzle inside a building that is not exposed to a lot of UV light. I have encountered many customers who are struggling with getting their image to appear only to find out they are washing the image out outside IN THE SUNLIGHT! Because the sun is blasting UV towards the earth, the image you just burned will get over exposed and will not come out.   P.S. Don’t coat your screens outside either!

·         Over And Under

Nailing the correct exposure time for your emulsion can be very difficult, but at the same time very easy. It is very important to ask your sakes rep or supplier about their recommendation on how long you should expose your emulsion. You can also use an exposing calculator. If some or none of the image comes out during wash out, you are experiencing an over exposed screen. Over exposure can result in the loss of detail or the lack of any image and is cause by exposing your emulsion to UV light for too long. Under exposure can result in a lack of sharp lines, pin holes, or your image completely washing away, and is caused by exposing your emulsion to UV light for too short of a period. Under exposing is also a common cause for emulsion to getting locked into the screen and becoming hard to reclaim.

·         Great Film, Great Responsibility

To have to most success in burning a successful image into your screen, one must have very densely printed film. If you can see light though the printed area of your film, so can your emulsion! Using the correct methods to print film is very important to the success of your image. Toner Aid can be used on the film after printing with a laser printer. All black ink cartridges can be used in ink jet printers to insure dark prints. Always check the film before exposing to avoid any issues that will incur.

·         Emulsions

With there being many different types of emulsions available, always check with your sales rep on the specs of the emulsion you choose. Here are the different types of emulsions:

1. Pure Photopolymer: photopolymer emulsions are ready-to-use direct emulsions that provide ultra-fast exposure times (5x faster than diazo, 2x as fast as dual-cures)

o   Excellent resolution and definition

o   Photopolymer emulsions are pre-sensitized and should be handled under yellow safe life conditions before exposure.

o   Shelf life is up to 2 years

o   Stirring is not required

2. Dual Cure: Superior resolution and definition capabilities

o   Has resistance to both solvent and waterbase inks.

o   Handle under yellow safelight conditions.

o   Add the diazo solution and mix thoroughly

3. Diazo: formulated for use with waterbase, solvent and plastisol inks.

o   Produce stencils with excellent mechanical resistance, good resolution and edge definition.

o   Add the diazo solution and mix thoroughly.

o   Handle under yellow safelight conditions.

Always be mindful of the type of emulsion you are using while you are exposing your screen!

·         Light Source

Like emulsion, different light sources can result in different exposure times for your screens. When buying or making an exposure unit, please refer to sales rep on how that unit is designed to work. When exposing screens, make sure that the distance and range of light is accurate for your set up.

Keep these tips in mind when creating your image for your next job, and you will surely see a difference!  

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