The wide-format printing revolution

Ink is a small word, but it encompasses what has evolved to become a key staple consumable that is now used by most modern signs and graphics producers, and which now figures in most of the industry’s colourful and increasingly imaginative output in some way. Ink also draws a fundamental distinction between printing hardware with the choice of system being primarily influenced by the ink species it runs.

Today’s inks are truly remarkable works of chemical and physical engineering. They rely on sophisticated reactions within themselves in order to become fixed and durable on the substrate to which they are printed, any yet they can be reliably jetted in the liquid state and are stable when stored.


Some inks cure in UV light and yet the output they yield remains stable in daylight conditions. Other inks rely on the evaporation of solvent components or on temperature initiated curing and yet they remain printable for extended periods of time in the hardware's ink delivery system. Digital inks bond obligingly to a wide range of substrates and yield results durable enough to endure extreme applications without complaint or failure.

Without a reliable ink, even the most sophisticated printing system is literally just inert hardware. Ink is arguably the most complex of all the components that comprise a modern printing system. Should the ink fail, evidence of its issue is reflected in poor or unsaleable output or in print hard-ware that has seemingly slipped into a coma and that may require a skilled engineer’s intervention to rescue.

Ten to the minus twelve

Hardware manufactures build printers around the ink those printers deliver to the substrate. Hidden deeply within
the undocumented parts of the inner hardware systems that actually jet the ink to the chosen substrate, subtle influencers that determine performance and quality conduct a very delicate interplay.

A waveform that drives a printhead and that works well for one ink species may not even jet an unsupported ink or may do so badly. What hardware design tries to jet as an impossibly fine filament of liquid that collapses in flight to form a single, perfect primitive printed dot, may, with ink of another design, fracture into a shattered stream of satellite drops that land with a splash and that produce comparatively poor results. Much of the objective testing that ink undergoes is concerned with droplet formation as it is a subject that influences quality at a fundamental level.



Ink droplets, as jetted by modern printers, are so small as to defy conventional understanding. Measured, usually, in pico-litres, the widely held notion of a drop existing in the fashion of something dripping from a tap does no justice to a generated droplet in the world of inkjet inks. To get a pico-litre of ink, or of any liquid, you have first to take a litre of the liquid in question and divide it into a million equal parts. Next, take one of those parts and further divide it into another million parts. Each of those parts will be one pico-litre.

A pico-litre, or several of them in a single collective, in flight resemble something more akin to smoke than to liquid. And yet, bound up in each and every barely visible droplet of ink that is fired, is the means to deposit vivid colour on a substrate and to leave it there in a durable form. Inks are more than simple coloured liquids, they are sophisticated assemblies of chemistry with precisely designed physical properties tuning them within a very tight sweet spot to both application and to hardware.



Inks are broadly divided into types or species determined by the primary ‘vehicle’ in which the colourants they carry are dispersed. Aqueous inks use water as the vehicle and are generally, therefore, not compatible with the uncoated, plastic-like substrates, such as vinyl, commonly used in the sign and display industries. Solvent based inks work well with these materials though and exist in some variety. Latex inks rely on a heat-initiated bond and work with a broad range of popular substrates as do UV inks which use a curing regime driven by UV light. Recently, solvent based UV inks have been introduced that combine benefits of two species. Sublimation inks are used in specialist textile printing processes among others. Ink is usually dedicated to its hardware.

Broadly speaking, the most common ink sets used in the production of signs and graphics could be described as four colour inks. Cyan, magenta, yellow, and black (CMYK) inks are used to deliver the wide range of colours we are used to seeing in printed results. The range of colours a given ink can deliver is referred to as its ‘gamut’. The available gamut varies among inks of a given type with the best naturally liberating more or better colour.

The range and quality of colour that is available with a given ink can further vary given the substrate that is being printed upon. In order to deliver the maximum gamut, the substrate must comfortably accommodate sufficient ink to render the fully saturated base component colours and still dry properly. If the substrate cannot handle its ink, the ink has to be limited and this cuts into the range of available colour dramatically. Taken to the other extreme, depositing more ink than is need-ed to render a base component colour accomplishes little, it just distorts the gamut into territory that has little practical application for everyday print.



Ink may be installed into the target print hardware in a basic hardware supported configuration, CMYK or where more heads are available other configurations may be used, for example CMYK-KYMC. Reversing the ink order enables the printing of the ink in the same order in both head directions, this reduces or eliminates chromatic aberrations that may be noticeable in finished print as a particular subset of a higher order of issues known generally as ‘banding’.

More colours

Other ink colours have been introduced in pursuit of enhanced quality. In addition to the regular CMYK set, light coloured components may be used, in particular light cyan lC, and light magenta lM. Contrary to widely held belief, these additional ink colours do not produce a wider gamut directly, but are responsible for smoother gradation benefiting the production of high quality output in particular.

Gamut extending colours are known in inkjet inks, many are designed to deliver punchier advertisers’ colours. Blues and reds in particular are designed to add more impact and help out-put to reach parts of the spectrum that the standard web offset press colours (SWOP) cannot reach.

Textile printing makes a case for yet more colours and ink-sets containing oranges, browns, and greens, among other colours are known. Such inks are particular to the textile printing process and have no application in the rounder subject of graphics.



In relatively recent times, metallic ink has been made available for some digital ink species and this can serve as an under-colour for other inks in the set. This addition liberates a lot of creative potential and produces results that were at one time the exclusive province of printing businesses with a foiling capability or with screen-process printing in their offering.

White ink is regarded as a desirable thing to have and many modern ink-sets now have a white component. White varies dramatically from one ink species to another with the more opaque variants usually to be found as part of a UV cured ink-set.

White is typically used in the role of an under-colour supporting the production of print on substrates where an absence of a white base would other-wise rule the substrate out-of-bounds. If, for example, you anticipate printing coloured output on dyed-in-the-mass substrates such as coloured foam boards, you will have to laminate and cut a white background on the board to achieve accurately rendered detail. With white ink equipped, you simply print the output much like any other and the result will be well rendered detail sat in the self-coloured back-ground.



White inks feature among the solvent species too and can be used to much the same end as the UV species. White solvent inks have found a very fertile application space in the window graphics sector where, printing on clear films with white imaged fields produces extremely attractive images that really ‘pop’ and add interest and detail to otherwise blank expanses of glazing. Quality can be simply jaw-dropping with good design lifting the graphic further.

That ink and hardware combinations work at all is a subject of wonder and a testament to the capability of the chemists and engineers who conspire and bring the whole offering together. The fewer ‘off-piste’ variables that are introduced into the mix, generally, the more reliable and better the print delivery system will be. For this reason, print hardware, as robust as it may be, tends to produce more consistent results if it is used in a consistent environment. Ink, is, or ought to be, a constant in this system. Once working well and understood, any disruption to the components comprising the whole system, and ink in particular, will change the results obtained.



Well maintained hardware and the right, properly stored and used ink can of course be maintained over time. One critical component that will either flatter or badly degrade the jetted ink is the substrate it is delivered upon. Signs and graphics producers have little choice given the range of output they produce but to use a range of substrate types. Simply swapping from one substrate type to another though will exercise ink beyond its design limits and produce sometimes awful results. To ensure that ink/substrate combinations work in an optimal way, the system's behaviour needs to be influenced to suit. This is the role of profiles.

Profiles are, or should be, ink specific. Profile are produced by printing with the ink being used on the target substrate. The pattern of print this process produces is assessed to determine the substrate’s limits in terms of handling the ink. This limit is coded into the profile and subsequent processes then add information needed to render colour accurately.

O Factoid: Ink is primarily classified according to the type of carrier it employs. O

Some substrate and ink combinations are simply not capable of yielding the whole range of colour that would be needed to produce typical four-colour output. An example might be a filmy textile designed to be printed direct. Despite this obvious limitation, the ink/substrate combination still may yield a result that is useful in some applications—a retail window display for example. Such materials benefit from an ‘ink-limited profile’ where the ink, through not fault of its own, is almost choked off so as to support better drying. Some inks do better than others. It is a question, often, of ink design and quality.

Ink then, is a critical component of any ‘system’ or end-to-end process that yields print. In the wide-format world where most of us operate, ink has not only to work, it has to work very hard.

First to last

Most printed output beyond the core of the signing market is not on nodding acquaintance with the durability needs of the signing and allied industries. Our applications are extreme and really exercise ink design.

In the dried or cured state and on a suitable substrate, ink used, for example, in the creation of a vehicle livery, has to endure extremes of temperature fluctuation and numerous wet/dry cycles. Quality inks are up to this job. Poorly designed or cheaply made inks are often not. Poor quality ink comes at a shocking price when the damage it can inflict on reputations and customer relationships is considered. The differences in price when distilled to the square metre leave many to question the worth of putting durability on the line. Penalties may be paid in terms of overall hardware reliability too.

Ink design and hardware are inextricably linked. If you have a printer designed to deliver ecosolvent inks, then jumping ship and putting latex inks in it is no more an option than deciding to run your car on water. Even if you were to resolve the engineering supply side of the equation, the heads, drying regime, on-board maintenance and numerous other factors conspire against you getting a single drop you can print out of the printer. Eco-solvent or UV inks will not do any better in a printer designed to handle latex.

The thought of alien fluids pumping around your pride and joy should at least raise the question of whether you need to explore exotic alternatives to what has been designed from the ground up to work and that usually does—brilliantly. Your primary and superordinate goal in owning and operating a wide-format printer is, to produce and sell output that your customers are happy with and to make a profit doing so.

Ink is such a deeply coded part of printer genetics that, to a man, printer manufacturers supply their own. The attraction of using a manufacturer-owned or sponsored ink is that it simply works. Pioneering work undertaken by various parties in history bought alternative ink species to hardware that was often only marginally suited to it. Durable output was the consequence of such efforts and many agree that it provided a commercial stimulus for hardware developers to fashion and manufacture durable inks of their own.

Today’s hardware manufacturers’ inks fully deliver the durability side of the equations and the process of producing durable print, with a properly tuned profile and suitable substrate has been simplified to the point where it is practically a touch-button operation.

Ink, like all consumable components used in signs and graphics manufacturing, comes at a price. The nature of the output produced though means that, while a square metre of a given substrate is a fixed cost, the ink jetted upon it is not. Ink coverage is variable and depends on subject matter and the way it is printed.



Many companies take the worst case view of cost when pricing output and assume that ink will be jetted in high concentrations. Doing so enables the calculation of a base cost upon which whatever profit factors are needed can be applied.

Modern ink design yields results that are remarkably resistant to the effects of most weathering agents they come into contact with. Most though benefit further from laminating. Ink when printed either cures or dries into a layer that is very thin and that can be dam-aged over time and laminating helps keep print in good condition.

Laminating, typically, involves the application of a filmic layer of protection on the print. This helps to reduce the amount of UV light that the ink is exposed to and so extend the useful life of the print. Laminates are available in a range of finishes including ones that are very highly glossy. A glossy laminate helps to lift the perceived contrast the print displays and is said to make it ‘pop’.

A primary purpose of laminating is to impart better mechanical durability. Modern ink species use a variety of means of adhering to a given substrate, all though are subject to progressive removal if subjected to the sort of mechanical forces encountered, for example, in a car wash. The effects can be greatly exaggerated where print is applied on tight radius corners. It is not unknown for aggressive washing to remove the ink layer entirely in such locations. Laminating completely mitigates the effect of washing on the ink layer and keeps prints functioning optimally for years.

Whether laminated or not, the products of modern ink species are today pressed into more application than the inkjet pioneers would have imagined possible in the graphics sector and in other  industries. What makes one ink species better than another in a given application is a somewhat subjective matter if the functional requirements are satisfied.

Durability is a major area of concern to anyone operating a signs and graphics business as so much of the output is concerned with outdoor applications. Today’s inks deliver that durability whether they are of UV, latex, or solvent based designs.

Today’s ink species, and the right substrates, also deliver larger-than-life colour with deep saturation and very punchy contrast that appeals to print buyers. Photo-like fidelity is often seconded to what might be best described as ‘impact’ and, properly printed, the solvent and latex species in particular do not disappoint. 

Mission critical

In attempting to land on a precise answer to the question ‘what ink is best for me’, a considerable number of fac-tors have to be considered. Right up there in the solution set though the answer, ‘one that works,’ should be considered. If for example, you are likely to be pursuing applications where your output needs almost photo-like fidelity and gets examined at close quarters, then you may struggle to come to terms with the texturing that some UV ink sets yield. UV inks though, are very accommodating when printing on inert substrates that solvent based inks would simply run off.

If your business model is centred around hosing down acres of very short-term banner material for inexpensive trade output, your printer choice might dictate a given ink type and the same argument holds for someone taking a much broader view of the market.

Some businesses operate outside the comfortable space where they exclusively run a printer manufacturers’ own ink solution and some thrive doing so. Others encounter difficulties that make the supposed savings look trivial and would never step outside the original ink-set at any price.
Ink is a large and complex subject. Every saleable square metre of output that is produced owes its very being to an ink, hardware and material combination that simply performs according to expectations and that operates with touch button simplicity. That kind of reliability and performance comes at a price. Thanks to the pace of development, competitive forces and the brilliance of its manufacturers, it is a price that any business with a reputation to defend can afford.


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