A particular stylistic hallmark of much current painting is what we'll term the 'multi-chromatic brushstroke'.
Achieved by loading a brush or knife with several colours, it hovers somewhere between traditional blending techniques and highly self-conscious, decorative gesture. It also closely resembles the action of the 'natural media brushes' commonly found in image-editing software such as Photoshop or Painter, as well as an increasingly wide range of downloadable apps.
Top: Tomory Dodge, detail. Left: Yago Hortal, detail
As the term 'natural' would imply, such tools are designed to emulate genuine paint.
Yet the results, especially in Photoshop, are not entirely convincing. Programmed to generate simultaneous strands of intertwined colour, the visibility or strength of the virtual pigments never varies or wavers, resulting in consistently candy-cane-like striated or dappled line.
Nevertheless, the Photoshop brush probably constitutes the most widely used of all digital editing tools, and the familiarity of its oddly alluring simulacra is closely followed by commonplace effects such as smudging or liquefying - both of which produce equally intense approximations of gooey, striated paint. Note 1.
The computerised brushstroke may fall short in its attempt to replicate genuine media, but its dramatically hyper-real appearance seems to find an increasing echo in today's painterly production.
Is it something of a contradiction to begin our overview of the multi-chromatic line with work by artists who either employed such a technique before the advent of Photoshop, or for whom the software may never have served as a reference?
We'd suggest instead that, since the gesture has gained much of its currency largely due to its virtual resonance, artists already associated with such a trope now exert considerable influence within a visual landscape increasingly shaped by the capabilities of the computer.
In terms of such predecessors, few are more closely associated with the multi-chromatic brushstroke than French painter Bernard Frize.
Frize's long career (he was born in 1949 and has exhibited since the 1970s) is chequered, with relatively little recognition outside his homeland until the 1990s. Yet his influence on contemporary painterly discourse - and therefore other artists - is decisive.
Frize's work is process-driven, the coloured striations which have become something of a hallmark since a first appearance in the mid-1990s achieved using specially adapted brushes or a team of painters working in careful unison.
No matter how far removed conceptually from the digital workspace such resolutely hands-on practice may be, there's little doubt that Frize's carefully orchestrated mark-making has gained a new sense of familiarity via uncanny echoes in the capabilities of today's software.
The use of multi-chromatic line has always been a signature aspect of British artist Fiona Rae's painting, predating any exposure to digitisation (the first two works shown here were completed in 1990, the year that the first version of Photoshop was released).
Nevertheless, Rae's practice is especially interesting insofar as it straddles the analogue/digital divide: achieving fame in the late 1980s, she began to utilise Photoshop in 1999 after meeting her husband, the painter Dan Perfect, "...who is extremely computer literate and who encouraged me to explore using the computer for my work."
Accordingly, from this point Rae's paintings begin to exhibit subtle yet substantial shifts in style and technique, including enhanced use of elaborate, hard-edged motif (left), and more extensive layering throughout the picture plane (below).
Rae's own description of this transition provides fascinating insight into the use of image-editing tools within an otherwise traditional painting practice:
"In 2000, I started using contemporary fonts ... as geometric shapes in the paintings. Using Photoshop, I planned scale and composition and added flares and special effects to the graphic symbols which I could then replicate in oil and acrylic paint on the canvas."
Although Rae has also emphasised (in slight contradiction to her statement above) that she has never used the computer "... to plan making marks, brushstrokes, drawing, or anything gestural or painterly", she credits Photoshop with a major role as a testing ground for colour schemes:
"I find that really helpful – I often take a digital image of a finished painting and flip through lots of colour versions to see what else might be possible."
It's a facility which, as we shall see, other artists find equally indispensable.
Tomory Dodge's splintered brushwork - a mass of thick, densely clustered marks - has always, to some degree, made use of multiple colour within the same stroke.
From about 2006 onwards this tendency resolved itself into full adoption of the multi-chromatic line, a signature characteristic which has become steadily more emphatic throughout the evolution of his work.
In a 2007 statement Dodge expressed his interest in "... a kind of apocalyptic fantasy that seems to lurk below the surface of the American psyche" and goes on to explain that "One of the ways I try to reference this is to imply a kind of sickly, if rapturous, delirium".
Candy-cane strands of multi-hued paint provide a perfect manifestation of the "sickly yet rapturous" atmospheres he seeks to evoke.
In recent years, Dodge has moved stealthily from near-figuration to abstract painting, his latter works often provoking comparison with Gerhard Richter.
But although Richter's influence is certainly plausible, Dodge's vibrantly striated non-representation provides an entirely logical extension to his earlier practice, while his technique of applying combinations of colour directly from the brush or knife - rather like working with stripey toothpaste - differs hugely from Richter's own blending methods. Note 2.
Whether there's a tangible connection here to the computerised renderings specifically referenced by artists such as Kerstin Brätsch or Glenn Brown may never be known; but like Bernard Frize and Fiona Rae, Dodge's intimation of digital-painterly techniques has proven more reflective of current tendencies than work by many of his peers.
It's also certainly the case that more recent works, such as those shown left and below (2008 and 2010), appear to very directly address digitisation by employing various other procedures typical of technology's increasing influence on painting. These include conspicuous layering, gradient fills, and the recently voguish shearing or 'self-reflection' technique. Note 3.
Emerging painter Yago Hortal revels in the use of vibrant colour fused within multi-chromatic lines and forms.
His technique closely approximates digital effects, and is as reminiscent of Photoshop's liquefying filters as its simulacrum of the brushstroke (he also makes extensive use of gradient fills).
In addition, his accent on bright, intensely hued pigment seems an attempt to emulate screen-based RGB colour combinations: light-filled renderings that resist approximation in paint.
Nevertheless, although Hortal's work very aptly illustrates our identification of the multi-chromatic brushstroke within recent painting, it clearly runs the risk of appearing essentially decorative - a danger that's particularly inherent in the translation of digital effects into paint.
In more recent work, such as KL47 (2011; left) and KL38 (2011; below), Hortal attempts to resolve this dilemma through a sharper focus on texture and form that adds thick wedges of impasto paint to flat surface.
Such devices very abruptly remove the works from the realms of digitally simulated paint to which they owe their initial debt.
Photoshop is, of course, a professional (and relatively expensive) design tool, but for many of today's undergraduate artists, basic tuition in both Photoshop and Illustrator forms an integral part of their course content.
The general public, meanwhile, have increasingly wide access to low-cost, alternative image-editing options.
Rudimentary (although constantly improving) drawing tools have always been bundled with the Windows operating system, and a wide range of tablet or phone-based apps extend the reach of the digital painting experience.
General familiarity with virtual painting - and its hyper-real results - is becoming ever more entrenched.
When not applying multiple colours within the same stroke, another of Dodge's favoured techniques involves 'emulating' such application by creating rainbow-like contiguous bands of colour.
Dodge has made very extensive recent use of a mirroring technique in which one 'half' of an image appears to reflect the other, but he's far from isolated in his use of this trope.
Interestingly, as well as constituting an effect that's simple to produce with image-editing software, the implication of reflection also implicitly posits a meeting between the real and the virtual: a fitting motif for the issues with which this article is concerned.