Goal

The goal of this exer­cise is to develop the proper tech­nique for coat­ing a screen for printing.

Objective

The objec­tive of this exer­cise is to use a scoop coater to apply photo reac­tive emul­sion to a screen and prop­erly store the screen for drying. 

Background Reading

• Mac­Dougall, Chap­ter 4, p 41–48
• https://​www​.youtube​.com/​w​a​t​c​h​?​v​=​K​k​-​8​F​w​s​6​7SA

Safety Notice

• Avoid pro­longed emul­sion expo­sure to skin
• Safety apparel required: gloves, safety glasses, ear plugs, respirator
• Safety Data Sheet (SDS) Index

Exercise

For com­plex art­work, a sten­cil made from photo reac­tive emul­sion is needed. The chem­i­cals harden after expo­sure to light and cor­re­spond­ingly block ink trans­fer. Proper emul­sion appli­ca­tion allows for qual­ity print­ing.  A dark room is needed to com­plete this process.

Part One

Emul­sion is light sen­si­tive, so turn on the safety light and turn off all other over­head lights. Remove the emul­sion stored in the fridge. Open and mix to ensure con­sis­tency. Use the appro­pri­ate scoop coater for the screen size. Fill the coater about half full.

Warn­ing: Do not allow emul­sion to be exposed to light any longer that necessary.

Part Two

An even coat of uni­form thick­ness is what is required for proper future steps. Tip screen at an angle. Place coater near bot­tom edge of print side. Tip the coater towards the screen and allow emul­sion to touch screen. Press firmly and draw coater upward coat­ing screen. Tip the screen toward coater and roll coater back to allow emul­sion to retreat from edge. Make a sec­ond pass to ensure all areas are cov­ered and to remove any access emul­sion in cen­ter of screen. Repeat for squeegee side. Check first side again and clean up as needed. Scrape thick, access deposits from the edges using a card or spatula.

For large screens, use two hands on the coater and a wall clamp to hold the screen in place.

Part Three

Store screen in dry­ing cab­i­net with print side (wet emul­sion) up and ID label fac­ing the door. Close and latch door. Start timer for dryer.

Return excess to con­tainer. Promptly wash tools. Pay care­ful atten­tion to coater to avoid dam­ag­ing edges.

Warn­ing: Do not allow emul­sion to freeze. Do not adjust fridge. Do not store food or bev­er­age in fridge.

Technical Specifications

• Ulano LX-660 emulsion
• 20 x 24 in. Yel­low 230 screen

Assessment

• The fol­low­ing rubric posted on D2L will deter­mine assign­ment score: Exer­cise Grading

Techniques

Coat­ing, dry­ing, clean up

Supplies

Emul­sion, screen, scoop coater, dry­ing cab­i­net, mix­ing tool

Deadlines

Monday/Wednesday, Jan­u­ary 30/February 1, 2017. Exer­cise Given.

Monday/Wednesday, Jan­u­ary 30/February 1, 2017. Observed by instruc­tor as part of group demonstration.