Safelight: A safe light that is used when working with photosensitive materials like emulsion or capillary film to prevent exposure to ultraviolet light. Also used in dark rooms that use photographic films. Typically these are two very different types of light with the dark room light for film using exclusively red safe light while a screen room can use amber light or yellow light.
Sawtooth: A jagged edge appearing in a stencil image that looks like stairs steps.
Scoop Coater: A metal trough used to dispense emulsion to coat a screen.
Screen: A wooden or metal frame with screen mesh tightly attached to it.
Screen Abrader: A chemical agent used to roughen the surface of screen mesh to aid in the adhesion of capillary film.
Screen Clamps: A mechanical device used to hold the screen in place during printing.
Screen Clogging: A condition when ink dries in the mesh preventing ink from passing through the stencil.
Screen Mesh: Woven material made of polyester, nylon, or stainless steel with uniform openings that will be attached to a screen frame.
Screen Frame: The frame in which the screen mesh fabric is attached.
Screen Opener: A chemical that is used to remove clogged ink from a stencil. These are hot solvent chemistries that can affect emulsion and make reclaiming difficult. Use sparingly.
Screen Printing: Printing method where ink is printed through a stencil with a squeegee.
Screen Stretcher: A device used to stretch mesh over a screen frame prior to being glued down to the metal or wooden frame.
Sensitizer: A chemical added to liquid emulsion to make it harden when exposed to ultraviolet light. Diazo and SBQ sensitizer are the two main types of emulsion sensitizers.
Serigraphy: Technical fine art term for screen printing.
Shelf Life: The length of time a product can be safely stored before it loses its ability to work properly.
Shirtboard: A flat surface used to hold the substrate during printing. Also known as a platen.
Side Clamps: A clamping system on a screen printing press in which the screen is held in place by clamps located on the side of the print head.
Simulated Process: A screen printing technique typically used for the reproduction of photographic or full color images involving the use of hand or color separation software using a certain number of opaque inks to render a full tonal image in color. This opaque printing technique can print on all shirt colors and typically uses 8-12 colors. It differs from index printing in the type of dots it uses. Simulated process uses halftones, index printing uses a fixed sized random stochastic dot.
Sizing: Chemical agent used to increase the weight, crispness and luster of a garment. When heat from a dryer or flash cure unit heats up a garment, sizing agents begin to burn off creating a characteristic odor and smoke.
Snap-off: Snap-off is a condition that describes the lift-off action of the mesh from the ink and substrate during a print stroke. Controlled by screen tension and off contact between the screen mesh and the substrate.
Sodium Metaperiodate: The key or main ingredient along with water used in most screen reclaiming solutions.
Soft-hand: The feel or texture of a print after it has been cured.
Solvent: A petrochemical liquid used to clean inks from screens, or as a thinner for solvent based inks, or as a screen opener.
Solvent Based Inks: Non-plastisol inks such as enamels and epoxy inks typically used for the printing of hard goods and other non textile products.
Special-effects Inks: Types of special effect inks include metallic, shimmer, glitter, high, density, glow in the dark, puff, reflective, photochromic (color change), suede, gel, black light and others.
Spray Adhesive: A type of platen adhesive used to keep the substrate in place during printing.
Spread: Adding a slight outline to an image in computer graphics for the purpose of compensating for printing press mis-registration.
Spot Color: Artwork that utilizes specific shades of ink to create the design. Color is separate and unique and does not combine to form secondary colors. Color stands alone within the design.
Squeegee: A tool made out of wooden or metal with a rubber blade captured in a clamping mechanism and is used to push the ink through a stencil by pulling the squeegee across the open image area of the screen.
Squeegee Angle: The angle in which the squeegee is held during the printing process. More angle equals greater ink laydown, less angle aids in details and to shear viscous inks like plastisol.
Stencil: On an exposed screen the emulsion portion containing the image to be printed.
Stretch Test: Stretching the print on a garment to see if it cracks indicating if the print has been fully cured or not.
Strike-off: A sample print.
Stroke: The pulling of the squeegee across a screen to produce a print or the flood stroke that fills the ink well of the image.
Sublimation: The process of heating inks or fabrics causing the dyes to release a gas that can color polyester fabrics or treated cotton where the gases create the color and not the ink. It can also refer to fabrics like red that sublimate the dyes used to color the fabric and migrate into the plastisol print.
Substrate: Term used to refer to the item that is being printed.
Square Dots: Used to describe the type of dot used for index printing, also called stochastic dots.