What is screen printing?
Screen printing is a process though which ink is mechanically applied to a substrate via the use of a screen and squeegee. In its basic form, screen-printing is a very simple process. Over time rather sophisticated software, machines and techniques have been developed and we now use those to produce our product. Screen-printing can be used to “decorate” many different substrates from ancient eastern wall hangings to Andy Warhol’s fine art to signs, billboards, computer circuit boards and more.
What is spot-colour?
Spot-Color is the term used to describe separation and printing with one ink colour for every colour in the design. Each colour that makes up the composite image will be printed using a separate screen.
What is 4 colour process?
4-colour process is a more advanced separation and printing technique that uses 4 colours of transparent ink to produce the colours from the original design. The four colours, Cyan, Magenta, Yellow, and blacK ( CMYK ), are printed as halftones that interact with each other to create colour and tonal values. A wide spectrum of colours can be represented but some colours are impossible to produce.
4-colour process is used mostly for photographic or digitally created designs because many shades and colours can be created with only four screens. High screen counts and screen frequencies are required to create the tiny halftone dots.
What is index colour?
Index colour is another separation and printing technique that uses a few ink colours to produce a full colour print. Unlike 4-colour and simulated process, index colour does not use halftones. Rather, the design is broken up into tiny square areas of solid colour. These squares are very small ( 200 per inch ) and when printed they blend together to trick the eye into seeing colour shades and variations.
Index colour works well on both white and colored garments but generally takes more ink colors to represent a design with lots of colour variation. Index colour has the added advantage that you can pick the exact ink colours to use. This way you can more accurately represent colours that are difficult to produce using a “process” method. It also requires high mesh counts to print the tiny squares properly.
What is screen count or mesh count?
The mesh count is the number of threads per inch (tpi) used to weave the mesh. The mesh count defines basically two things: The thickness of the ink deposit and the size ( or lpi ) of halftones that can be printed.
The lower mesh counts, 85-110 tpi, have a relatively large thread diameter and more space between the threads ( called “open area” ). This allows for a thicker deposit and more ink to pass through the screen. Typically, lower mesh counts are used for specialty inks and when a thick deposit is needed on dark garments.
The high mesh counts, 305-355 tpi, have a very small thread diameter and less open area. These are used when fine detail and high halftone lpi are needed.
In the middle, 200-255 tpi, are general purpose screens for spot color, good detail and acceptable halftones.