Screen- printing - Glossary

C

Clogging up

Is the slow drying/ clogging up of the holes in the mesh of the colour. Nothing helps but cleaning!

Coating

Coating means the even appliance of light sensitive, liquid direct emulsion onto the mesh. The coating-through helps in the process.

Colour separation

Colour separation means the manual or digital separation of a multicoloured printed matter (motif) into the separate colours (printing rounds).

Colour lift-off

Is the area of the mesh not used for the printing process- the space between the border of the frame and the printing motif. Other then in textile printing a lift-off is always required. Has the motif been copied to close to the frame this is not possible. Thus around six inches of space need to be left.

Continuous tone image

Is an image produced manually by sketching. drawing, or photography, that contains not only black and white, but a multitude of colours between these two poles. (Shades of grey, mellow tones, colour gradients, continuous tones) In screen printing such continuous tones can be simulated through nuances (posterization) and grids.

Copying apparatus

The light- sensitive stencil coated with coating emulsion is placed in the vacuum frame alongside the film. They are pressed against one another. Then the vacuum frame is place vertically so that the stencil can be exposed through a pane.

D

Develop (wash-out, rinse)

After exposure all non- hardened parts in the fabric are washed out.

Black parts on the film= not light transmissive = can be washed out

Transparent parts on the film= light transmissive= hardened by the UV light = cannot be washed out

Degrease

Degreasing means the in-depth pre-treatment/ cleaning of the mesh. Especially when using the mesh for the first time the screen should be degreased.

Direct emulsion

Light sensitive emulsion transferred to the mesh by use of a coating-through. (also see coating)

Drying racks

Drying racks used to be made from wood. Nowadays they are made from metal and are easily moved on wheels. The racks are made up of bars and are used for the drying out of freshly printed products.

E

Exposure

The mesh is exposed to a strong light source containing a UV- contingent with around 3000 to 6000 Watt. The timing of the exposure depends on the motif, the cloth, the texture of the fabric, the copying level used and the thickness of the coating.

F

Flooding

Before printing the stencil is flooded with colour by pulling it level across the print image with the roller. Then the cavities in the stencil are filled with colour (flooded). After each print flooding is necessary as the fabric dries quickly. If that happens cleaning is necessary!

Foldable masking film

A thin transparent foil of the size of the image to be printed is stuck upon the printing table. The foil is printed upon once and than used as a registration marker.

G

Ghost image

A ghost image is an old print image emerging through grinding colour pigments. To avoid ghost images a meticulous cleaning after the printing process is necessary. Other than that the only solution is a new mesh!

I

Iris print

Describes the simultaneous printing of two or more colours in one stencil. In each run two colours mix and each print is unique.

M

Masking film

Two level foil with a light resistant cutting level that is used as a copying master (film). Through cutting out and removing the light resistant level the motif for printing is singled out.

Mesh

Colloquial for the screen printing frame, fitted mesh, and fixed stencil.

Moiré

Are interference patterns that emerge through the overlapping of two or more half- tones. This can be used as a special effect, but generally constitutes a mistake.

O

One- hand squeegee

The One-hand squeegee is used for large formats. A mechanically guided but manually lead (by one hand) roller.

P

Printing order

The printing order means the order the colours are printed in. Most often one begins with the lightest colour, unless you want to achieve special colour effects.

Printing stock

The classical printing stock in screen printing are materials, such as synthetics (e.g.: PVC, polyethylene, polypropylene, polycarbonate, acrylic …) cardboard, paper, self- adhesive foil, textiles, leather, felt, glass, wood, metal, and much more.

Even printing on three-dimensional bodies is possible.

R

Reclaiming

Reclaiming describes the releasing and removing of the screen print stencil from the mesh by use of an appropriate solvent.

Register mark

Register marks are small paper or foil squares placed in angles towards one another to mark the printing image on the printing table. This provides a fixed position for the printing stock.

Registration

Is the name for the accurate fitting of the print device, the screen mesh and the printing stock in pre-print.

Roller (Squeegee) (Also see one- hand squeegee)

The roller serves to force the colour through he opening in the mesh. Profil and hardness of the roller may differ. For cloth round and soft rollers are preferable. The printed image can be influenced by the pressure applied with the roller.

Relief print

Rough texture and paste- like colour on printing stock result in an elevated relief- like print. Such effects can be achieved with transparent lacquer on matt substrates.

S

Screen lift-off

The screen lift-off is the necessary, minimal distance between the mesh and the printing stock that prevents sticking together and smearing. The screen lift- off depends on the mesh’s material, the technique of printing and the format that is printed in. (usually printing on textiles does not require a screen lift-off).

Serigraphy

An artistic variation of screen printing.

Substrate side

Substrate side is the name for the side of the mesh the printing stock lies on.

V

Viscosity

Is the level of thickness of the colour.

W

Wash-out (Rinse)

After the exposure the non- hardened parts are washed off the mesh. Thus the stencil is created.