A to Z of Screen Printing Terms

A

AccuRIP:

A RIP program which allows the conversion of gradients in artwork to halftones. See halftones and raster image processing.

Adobe Illustrator:

A vector artwork program which is popular among users of the Adobe suite of creative programs.

AI:

A vector file type utilised by Adobe Illustrator. See Adobe Illustrator and vector image.

B

Bleed:

When ink bleeds into fabric it is not supposed to. Much like the effect of a drop of ink on a tissue.

Block-out Pen:

Used to block off pin holes in a stencil before printing.

C

CMYK Printing:

Also known as four colour process printing, is the process of overlapping four translucent inks, cyan, magenta, yellow, and black in order to create photo-realistic prints. Can only be used on white garments. Similar to simulated process.

CDR:

A vector file type utilised by CorelDRAW. See CorelDRAW and vector image.

Conveyor Dryer:

Sometimes referred to as an oven or belt dryer, a conveyor dryer is the best method for curing inks into a substrate. Different types of ink have different curing times and temperatures that they have to cure at. Different substrates will also affect this process. See curing.

CorelDRAW:

A vector artwork program which is very popular in the screen printing industry due to its well-developed suite of tools and its ease of use.

Curing:

In essence, using a conveyor dryer to cook or "cure" the ink into the substrate. Different inks and substrates have different curing temperatures. See under cured and over cured.

D

Degrease:

To remove all foreign material, including all oils, from a screen during the reclamation process.

Discharge Ink:

Used in textile applications it, in essence, bleaches an image into the garment, leaving a natural cotton colour behind. Discharge ink may be dyed for colour but the colours will never be as vibrant as other forms of printing and dries in screens even faster than water based inks. Similar to water based ink and plastisol based ink.

E

Emulsion Remover:

Used to break down the hardened stencil on a screen.

Encapsulated Post Script (EPS):

A file format which can contain both vector and raster images and is very popular in the screen printing industry because of its widespread usability. One major drawback to this file format is the tendency for it to render slightly differently in different design programs.

Exposure Unit:

May sometimes be referred to as a UV light table or a UV screen exposure unit. Used to bombard screens which have been coated in emulsion with UV light. This will harden the emulsion into the screens which, in combination with a film positive, will create a stencil that screen printers will print through.

F

Film Positive:

A copy of the image to be screened which is printed in solid black on a transparent plastic sheet. Each colour to be printed requires another positive of its own. Film positives are used in combination with emulsified screens. See emulsion and exposure unit.

Flood:

Spreading ink over the surface of the screen. Similar to stroke.

H

Halftones:

Small dots used to screen print the illusion of any gradients and/or colour blending which was present in the original artwork.

Hand:

Refers to how soft or rough the print is.

I

Ink:

Used loosely to refer to any substance which is printed onto a substrate. See discharge ink, plastisol based ink and water based ink.

Ink Remover:

Used to dissolve plastisol based inks.

M

Mesh Count:

The number of threads on a screen per centimetre. A higher mesh count means a greater number of smaller holes than a lower mesh count. High mesh counts can be used for high detailed printing but thick inks cannot pass through them.

N

Newtons:

The standard tension measurement for all screens.

P

Pin Holes:

Very small holes in a stencil which will result in flecks of screen printing ink staining areas that are not meant to be printed. Can be filled in with a block-out pen.

Plastisol Based Ink:

Will not dry unless passed through a conveyor dryer even if left out in the open air for weeks at a time. This, combined with its opacity and longevity, makes it ideal for many screen printing applications.

Platens:

Also known as pallets. These are the boards that a substrate will sit on to be printed. In textile printing, they are often glued so that the garment will not move while being printed on.

R

Raster Image:

Any regular image made up of pixels such as a .jpg or .png file. This format is generally disliked for screen printing as image quality becomes lost when enlarging the image. Similar to vector image.

Raster Image Processing (RIP):

Optimises the quality of digitally produced film positives. See film positive and AccuRIP.

Reclaiming:

The process of washing ink out of a screen and dissolving the stencil to prepare the screen for the next job. See degrease, ink remover and emulsion remover.

Reducer:

A substance which can make an ink thinner. Reducers will often lower the opacity of an ink as well.

Registration:

The process of lining up a series of stencils to print different colours or parts of a design in the correct place. Often done by printing three registration marks which look like cross-hairs and lining them all up. They will be at a fixed point on every screen so that once they are lined up, the images will all line up as well.

S

Scalable Vector Graphic (SVG):

A vector image file type which is popular due to its almost universal nature and ability to be recognised by standard web browsers.

Screen:

Used in combination with emulsion to create a stencil for images to be printed. See mesh count.

Simulated Process:

Using a limited number of spot colours and halftones to create the illusion of photo-realism. Similar to CMYK printing.

Spot Gun:

May also be known as a spot cleaning gun. Used in textile screen printing, a spot cleaning gun is one of the few ways to get cured ink out of an article of clothing without leaving a stain.

Squeegee:

A rubber blade used to push ink through the stencil on a screen onto a substrate. Comes in various styles and flexibility.

Stencil:

Screen printing ink is pushed through stencils to create an image on the substrate. A stencil is the result of exposing a screen with emulsion on it to UV light while a film positive is placed between the light source and the emulsified screen. The area which was protected from UV light by the film positive will be soft enough to wash out of the screen with water while the rest of the emulsion will remain in place. See emulsion, film positive and exposure unit.

Stroke:

Pushing ink through the screen, usually with a squeegee. Similar to flood.

Substrate:

What is being printed on.

T

Trap:

A term used to describe a process at the artwork level resulting in the images from different stencils overlapping each other to "trap" unwanted colours from being visible without requiring superhuman accuracy and alignment.

U

Underbase:

The first layer of ink printed onto a substrate. Usually used for dark or coloured substrates, a good underbase allows the end result to be vibrant. The underbase is usually printed with a white ink or a discharge ink.

Under Cured:

When ink, especially plastisol based ink, is not cured for the proper length of time or to the proper temperature. This results in an image which will wash off after a few times through the laundry cycle.

V

Vector Image:

An image file category commonly used in screen printing artwork. Vector art can scale to an infinite size because it is based on mathematical equations as opposed to pixels. There are a number of vector formats available and every screen printing company will have a type they prefer to use. See encapsulated post script, AI, scalable vector graphic and CDR. Similar to raster image.

W

Water Based Ink:

Considered a more environmentally friendly option but cannot be used in all applications and is not as opaque as plastisol based inks. This, combined with its tendency to dry into screens before printing has been completed, makes it much less desirable for many printing companies.

Wash Out:

During the stencil making process, when the edges of the stencil "wash out" ruining the potential image. See stencil.