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What is silkscreen printing?
Silkscreen printing, or screen printing, is the process of passing ink through a taught mesh screen onto a substrate.
The screen is positioned over the substrate. A canvas, a piece of paper, a T-shirt or a circuitboard, for example.
'Blocked' areas of mesh act as a stencil.
‘Open’ areas of mesh let ink pass through.
Before an impression is made, open areas of mesh are 'flooded' by passing a squeegee or flood bar across the screen.
Once flooded, a squeegee is pulled across the screen with enough pressure to bring it into contact with the substrate.
Behind the squeegee, as the mesh peels away from the substrate, an impression is left behind.
This impression is a silkscreen print.
A common misunderstanding of the process is that the squeegee pushes ink through the screen to leave an impression. In fact, it is the film of ink left behind as the flooded mesh peels away after making direct contact with the substrate. This simple process hasn't only birthed modern masterpieces. from Robert Rauschenburg to Richard Hamilton, it has shaped the history of industry and design for over a thousand years.
When was silkscreen printing invented?
While it's true that innovative printmakers in Song Dynasty China made the world's first paper currency by passing ink through a mesh of human hair, silkscreen printing as we now know it is a 20th century endeavour – built on modern understandings of photography, fluid dynamics and photopolymers. In the wake of the squeegee, as the taught screen peels away from the substrate, a luxurious and consistent surface coating is left behind. This is what sets silkscreen prints apart. The first documented appearance of this specific process is a 1907 patent application submitted by Samuel Simon.
It is worth noting that contemporary screens are rarely made from silk. They are more commonly made from superfine plastic threads known, rather less catchily, as monofilament polyester. Early silk meshes were adapted from those used by bakers to sieve flower. Their synthetic counterparts – both finer and stronger – offer greater precision and consistency.
Serigraphy – what's the difference?
Silkscreen printing in fine art contexts is also referred to as serigraphy. The term was coined in the 1930s, prior to the popularisation of the medium by Warhol, by a group of artists who later formed the National Serigraph Society. The term comes from the Latin word 'sēricum' (silk) and the Greek word 'graphein' (to draw).
Stencils
Early screen stencils were made from carefully cut pieces of paper or fabric. In time, this evolved into the use of oil resistant materials painted directly onto the mesh, and finally into photosensitive emulsion – used for the majority of contemporary printmaking.
Screens are coated with emulsion using troughs. When a coated screen is exposed to UV light, the emulsion become insoluble. If areas are blocked from the light during this process, they remain soluble – allowing the screen to be 'developed' by using running water to wash the soluble emulsion away. It is the combination of insoluble emulsion (which resists the flow of ink) and open mesh (which allows ink to flow) that makes up a stencil. The emulsion’s photosensitivity is key to the process. It allows for the precise exposure of an image onto a screen using a film positive or digital equivalent.
The ability to replicate details from a photograph as a stencil enabled Andy Warhol to print his iconic portraits of Marilyn Monroe. He transposed an promotional photograph for the film Niagara directly onto canvas. The immediacy of the process and its capacity for repetition are what catapulted pop-art, and therefore silkscreen printing, into public consciousness – along the way making Marilyn's image even more iconic than it already was. Andy Warhol and his contemporaries didn't just popularise silkscreen printing, they legitimised it as a ‘fine art’ medium.
Preparing the screen
First, pick the right mesh count. This refers to the number of apertures (holes) in one square centimetre of screen. A higher mesh count (denser mesh) reduces the flow of ink, increasing the capacity for fine detail. A lower mesh count, meanwhile, is useful for large flat deposits and working with metallics.
Before printing, screens are coated and left to dry in a dark room. This is to avoid any unwanted exposure to UV light. Next, they are placed flat on the glass of an exposure unit with a film positive positioned between the screen and a UV light source. This process 'exposes' the film positive onto the screen. Afterwards, the screen is rinsed. Areas that were blocked by the film positive are washed away to leave behind open mesh. Afterwards, tape and screen fill are used to perfect the stencil and prevent ink passing into unwanted areas.
Make-Ready
There are many ways to skin a cat, and there are many schools of thought in printmaking. Most Avant Arte editions are created in partnership with Make-Ready. From the humble beginnings in a garage, Make-Ready is an upstart turned major player in the world of silkscreen printing – following in the footsteps of revered studios such as Domberger with obsessive precision and relentless technical innovation.
The name Make-Ready refers to the setup of the printing press – a fitting name for a studio that prides itself on thorough preparation, meticulous process and a pristine finish. We're unafraid to look towards screen printing’s industrial roots to advance our processes. Rather than make enemies of the future, we embrace developments in printmaking and combine them with tried and tested approaches. We've introduced UV-cured inks, semi-automatic printing benches and automatic dryers as the workshop continues to grow. The thoughtful use of high-tech equipment enables printmakers to focus on the thing that matters. Printing. There are so many variables to consider when crafting a silkscreen print, and the capacity to control them is what ultimately expands our creative possibilities.
Why so many layers?
Before printing begins, the reference work is separated digitally into component layers by an artworker. Far from a mechanical process with a predetermined outcome, there are a plethora of choices to be made. The two main approaches are 'spot' and 'process' colour.
With either approach, the precise alignment of each layer is essential. Every film is checked diligently against a 'key film' to ensure that it is exactly the same size. Registration marks are exposed at the corrners of each screen. The marks are lined up precisely during printing. Accuracy is vital for a sharp and well-resolved image.
Process colour (CMYK) separation
Process colour separation uses industry standard CMYK inks – cyan, magenta, yellow and black (the K originally referred to 'key'). Artworks picked for this type of printing are normally those that have continuous tone and photographic detail. Soft-edged separations layer coloured dots in varying densities and combinations, allowing smooth tonal transitions from delicate highlights all the way to deep shadows. The colours become continuous, as distinctions dissolve into a sea of imperceptibly-tiny dots.
Sometimes process colour prints also incorporate spot colours. The Aquarium by Szabolcs Bozo, for example, is made from a 12 layer process colour separation overprinted with twenty spot colours – adding pop, vivacity and widening the artwork's colour space with elusive shades like bubblegum pink.
Spot colour separation
Looking closely at Superglow by Paul Insect, you can see that it is composed from an array of radiant, individually printed colours. Many of these colours sit outside the achievable range of process colour. Spot colours are used when an image requires specific effects, particular vibrancy or isolated planes of colour. Printmakers mix inks by eye to match the corresponding colours in the reference artwork. Superglow represents this process in it's classical form, with sharp-edged fluorescent solids and diamond dust highlights.
Sometimes you'll notice in the specification of a print that the number of colours and layers differ. This can be for a variety of reasons. Often, layers are overprinted to refine tonality or achieve a heightened level of solidity. Alternatively, the same colour may be printed through different densities of mesh in different areas of the artwork to achieve variations in texture. It is also possible that a layer was used to make a specific adjustment during proofing, and the successful print sequence was recreated when printing the edition to ensure an exact match.
Proofing with precision
When printing, a job sheet is crucial. This document tracks all of the information at the proofing stage, and is invaluable for the precise replication of this process for the final edition. A printmaker will methodically print each layer, recording the parameters as they go – ink mixes, mesh count, print pressure and challenges they face along the way. For a 30-layer print this can take weeks, perfecting two or three layers each day. The process adds texture and physical depth to the surface of the artwork. Like rings in a tree, these material qualities represent the time taken to create it.
Then, we do it all again. Once the proof is reviewed, adjusted and the artist is satisfied, it’s time to print the edition. This will be a near-exact replica of the proof, often a little sharper, and is achieved with the help of a detailed job sheet.
Finishing flourishes
The inks used in silkscreen printing vary greatly – from water based pigments to UV-cured polymers – and it isn’t only coloured ink that can be passed through a screen. Sometimes artists want to add panache to their prints by incorporating special layers such as metal leaf, phosphorescent ink, glitter or diamond dust. To achieve these finishes, glues and varnishes are printed through low mesh count screens. The prints are then finished by hand, with adornments applied carefully to the glued or varnished areas.
The future of silkscreen printing
With the advent of high quality digital printers, you might assume that there would have been a decline in silkscreen printing. In reality, it's more prevalent than ever in both industry and the arts. The strength of screen printing lies in its adaptability. It can print on anything, from gallery walls to medical equipment. Although it is an industry in its own right, it is perhaps best understood as a technology utilised by many others.
In the art world, digital printing, far from acting in opposition to the screen, has become an opportunity for experiments and innovation. Hybrid prints meld digitally-rendered artworks with silkscreen finishes. The singular clarity provided by inkjet printers pairs well with the versatility afforded by the screen when it comes to special finishes and vibrant overprints.
However far technology advances, we'll likely keep coming back to the silkscreen. It's a process of continual renewal and reinvention. Yet, the longevity of the screen printing stretches beyond its technical application and into something more elusive. Ineffable, even. Tom Murphy, the founder of Make-Ready, says that screen printing often feels like a “struggle against entropy” – teetering on a tightrope between chaos and order. Serigraphy is a process of opposition. An opportunity for precision and finesse, but also one for drama. An arena of possibility.
In a world that is increasingly intangible, it is no surprise to see a newfound lust for material things. Silkscreen printing swims in the same nostalgic current as analogue photography and the resurgence of vinyl. It represents a juncture between tactile and digital, past and future. Whatever happens next, it will be there.
Inspired to collect some silkscreen prints? You're in the right place. Discover available and upcoming editions on Avant Arte.
Glossary
Substrate · The surface being printed on. Most often, paper.
Fluid dynamics · The scientific study of how liquids and gases move.
Photopolymers · Plastics that change their properties when exposed to light. Also known as light-activated resins.
Squeegee · A rubber blade that is used to bring the mesh of a printing screen into contact with a substrate.
Serigraphy · An alternative name for silkscreen printing coined in the 1930s.
Photosensitive emulsion · A light sensitive liquid that becomes insoluble under the influence of actinic UV (ultraviolet) light.
Film positive · Clear polyester film printed with pure black ink. Usually, in the context of screen printing, with an isolated layer of an artwork.
Screen fill · A water soluble solution used to block pinholes in an exposed screen before printing.
Mesh count · The core attribute of a printing screen, measured by the number of apertures in a square centimetre.
Reference work · The original artwork used as the basis for a silkscreen print.
Registration marks · Small crosshairs used during printing to ensure perfect alignment between subsequent layers.