8 / 4 / 2021
LEXUS’S PURSUIT OF PAINT PERFECTION
Colour and shape are the two qualities people will notice first when looking at a car and it’s this first impression that Lexus has sought to emphasise in the progressive development of new paint technologies and colours, coupled to the distinctive styling produced under its design philosophy, L-finesse.
The goal is to produce paint quality that is unique to Lexus, providing colours with depth and lustre that not only catch the eye, but will last, too. The Lunar Silver paintwork on the new LS flagship saloon has taken the technology to new heights, achieved through years of dedicated research, development and breakthrough innovations.
Lexus’s pursuit of an ideal metallic look yielded its first important results in 2003 with the introduction of Cosmo Silver, initially on the LS flagship limousine. This marked a significant evolution from a straightforward metallic finish to something that offered a much greater brightness and the fluid look of pure aluminium.
The key was precise control of the size of the aluminium flakes used in the paint to create an ultra-metallic look, giving an effect more like aluminium foil or chrome. This was achieved by selecting “radiant” materials, applying an orientation control technology for even arrangement of the aluminium flakes and using a multi-layer paint composition technique. With constant scrutiny for perfect quality, the result was an unprecedented metallic finish.
Breaking new technology boundaries with sonic paint technology
The next Lexus breakthrough was the development of sonic paint technology. Recognising that there were limits to what could be achieved using single base paint layer, Lexus developed its multi-layer composition technique so that each layer played a different role in the quality and appearance of the finished paint.
Sonic Titanium and Sonic Silver were the first Lexus metallic paint finishes made using the sonic process, initially introduced in the UK for the IS and GS saloon models from 2012.
Created by Lexus engineers in a five-year development programme, this technique produced a paint layer compressed to a thickness of just 12 microns. This brought the aluminium flakes floating in the paint into even closer and more uniform alignment. Used within the multi-layer finish, it brought new brilliance and shading to the cars’ bodywork, qualities enhanced by the precision of Lexus’s robotised paint process and the hand polishing overseen by its famous takumi specialist craftspeople. Although the sonic paint process requires more effort, when applied it needs fewer bakes in the drying process, so is more environmentally efficient.
The launch of the fifth generation LS in 2018 signalled another breakthrough in sonic paint technology with the debut of Manganese Lustre, a paint finish designed to project the dense, solid feel of a metal mass. This was achieved using a thin metal paint layer to create a metallic accent in the bodywork’s highlights, in combination with a dark grey layer that emphasised the design’s tapering form.
Crucially the sonic process was developed so that a 12-micron layer containing mica particles would contract to a thickness of just four microns in the drying process, increasing the level of reflectivity.
Lexus’s ambition with the development of Lunar Silver (introduced in 2020 on the new LS) was to achieve “the ultimate metallic texture.”
A spokesman explains: “To achieve this, we were very discerning in selecting the type of aluminium we use and how to orient it uniformly in the coating. Specifically, the aluminium is deposited as a thin-film vapour that is a smoothly aligned in an ultra-thin layer. This produces a strong metallic reflection with a mirror-like lustre and smoothness, with strong and deep shadow contrasts.”
In this latest development of the sonic technique, the paint film contracts to an unprecedented thickness of just one to two microns. Producing such an extremely thin film free from any unevenness requires great skill and a perfectly smooth underlying surface – achieved through close collaboration between the paint engineers and Lexus’s manufacturing team.
Lexus has a dedicated in-house laboratory where a team of around 30 members research high-level paint technologies. It also recognises the importance of close collaboration with specialist partners on all aspects of paint development, design and production, and has worked with Kansai Paint and Nippon Paint since the Lexus brand was founded just over 30 years ago.
While the research programme is carried out in Japan, perceptions of and tastes in colours and quality are studied worldwide with paint colour options adjusted to suit different regions and markets.
Trends and tastes are important, but Lexus believes colour also relates closely to brand image. For example, while there are now several colours available that use sonic technology, these are characterised by their metallic qualities – the effects of brightness and shading – rather than the colour itself.
For a more exclusive finish, Lexus’s technical centres in the USA and Japan and specialist thin film optical coatings and pigment producer VIAIVI Solutions worked together to produce Structural Blue. The lengthy project successfully produced a multi-layered pigment that replicated the iridescent blue of the Morpho butterfly – an effect created by light interference on the lattice structure of the butterfly’s wings.
Where conventional paints reflect less than 50 per cent of incoming light as visible blue colour, the level with Structural Blue was almost 100 per cent. Unsurprisingly, it required a highly specialised application process – no more than two cars could be painted in a working day. The colour was reserved for a special version of the LC Coupe, the LC Structural Blue Edition.