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New To Screen Printing? Here’s Some Terms You Should Know.

New To Screen Printing?

If you are like me, when I first came into the screen printer world, I was a little lost with the terminology. No one wants to look stupid not knowing a simple term. So here is a cheat sheet.

Block-out: An emulsion like chemical that is used to cover pin holes and to block out any area of the screen that you do not want ink to pass through.

Burn: To expose an emulsion coated screen to a light source to create a stencil.

Capillary Film: A light sensitive film, used to create a stencil, that when applied to a screen with water adheres to the mesh by capillary action.

Coating: The process of applying direct emulsion to a screen.

Conveyor Dryer: A belt dryer used for curing inks.

Coroplast: A solvent ink used in printing coroplast blanks.

Curable Reducer: An additive to plastisol ink to decrease viscosity.

Cure: The process of using heat to completely fuse plastisol ink. Technically incorrect term for “drying” ink.

Darkroom: A room devoid of light used for the purpose of drying screens coated with emulsion or capillary film.

Degrease: The process of washing a screen with a cleaning solution to remove all traces of dirt and oils prior to coating with emulsion.

Dehaze: using a caustic cleaning agent to remove ghosted images from a screen.

Diazo Emulsion A two-part photosensitive emulsion.

Discharge inks: Used to print lighter colors onto dark background fabrics, they work by removing the dye in the garment leaving a much softer texture. They can be tinted with color pigments but exact colors are difficult to control.

DPI: Dots per inch, is a measure of spatial printing or video dot density, in particular the number of individual dots that can be placed in a line within the span of 1 inch (2.54 cm).

Durometer: Unit of measurement used to describe the “hardness” of rubber. In screen printing, durometer relates to the “hardness” of a squeegee blade.

Emulsion: Photosensitive chemical in either liquid, roll or sheet form that is applied to a screen and used for the purpose of making a stencil.

Flocking: Consists of a glue printed onto the fabric and then foil or flock (or other special effect) material is applied for a mirror finish or a velvet touch.

Four-Color Process: Also known as CMYK or Full Color Process. A printing technique utilizing four ink colors (Cyan, Yellow, Magenta and Black) to print the entire color spectrum.

Full Cure: A state in which the plastisol ink film has completely fused, typically when a temperature of 320 degrees has been reached.

Halftone: A color or grayscale image that has been converted into a series of large and small dots.

Halftone Dot Types: Shapes of halftone dots. An elliptical dot is the ideal dot shape for screen printing. Round, square and diamond shaped dots are also used.

Infrared: Specific energy wavelengths which produce heat. IR radiation is typically used to develop the heat in a heating element of a flash cure unit or electrical textile dryer.

Manual Press: Press used for transfer ink to a substrate manually.

Mesh: Woven material that makes up the printable portion of the screen.

Mesh Count: The number of threads in one square inch of screen fabric, measured in both directions. The lower the number, the coarser the mesh and the larger the screen opening.

Micro-registration: a mechanical adjustment on the print head of a screen printing press used for precise movement and alignment when lining up or adjusting a print job.

Monofilament: Screen fabric woven from single strand threads.

Off-contact: A method of screen printing of having a slight gap between the screen and the substrate for improved printability.

Pinholes: Unwanted tiny specs that appear in the stencil after exposure.

PMS: Pantone Matching System a system for mixing various inks to achieve the specified color as determined by Pantone.

Positive: Also known as film or film positive. Any media used to completely block out UV light in the design area during the exposure process.

Print Side: The side of the screen that touches the substrate being printed on.

Reclaim: To remove old emulsion from a screen so the screen can be reused.

Reducer: A colorless ink additive used to lower the viscosity of the ink making it easier to print.

Registration: The process of lining up the screen image to the original art and/or separations on a printing press and/or exposure unit.

Retensionable Frames: Special frames that allow the mesh to be applied over the screen without the use of adhesives or stretching equipment. The mesh is drawn tightly over the frame using either a roller or telescopic tightening system.

Safelight: A light that should be used when working with photosensitive materials like emulsion or capillary films to prevent accidental exposure to ultraviolet light. A yellow “bug light” works well for this purpose.

Squeegee: Wooden or metal handled tool with a rubber blade used to drive ink through a stencil by pulling the squeegee across the screen.

Squeegee Side: The side of the screen the ink is applied to.

Spot Color: Color reproduced by an opaque, premixed, standard ink chosen from a color system such as the Pantone Matching System

Stencil: The portion of an exposed screen containing the image to be printed.

Step Wedge Test: Exposure test to determine proper exposure time with a series of stepped exposures on one screen.

Substrate: Term for the item that is being printed.

Tension: The “tightness” of the screen mesh, measured in newtons.

Underbase: A thin coating of ink printed first and cured to act as a base for which all other colors are to be printed on. Underbasing is usually required when printing multi-color designs on colored shirts.

Underexposed: Insufficient screen exposure time, resulting in a soft stencil that can break down prematurely during the print run.

Viscosity: Commonly perceived as the “thickness” or “thinness” of an ink.

Wash Test: Laundering a printed garment in a washing machine to determine if the print is fully cured. The ink will wash off of an undercured garment during the wash test.

Washout Booth: Booth used for washing out stencils and reclaiming screens.

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