Since business jets are used by corporations to ferry the CEO and other high-ranking executives from here to there and back again, how that aircraft looks is often an extension of the corporate brand. That means the corporate colours are reflected in the business jet's paint scheme.
From Caterpillar to Butterfly
Before an aircraft hits the paint bay, its skin is a shocking tone of green, and that's where the term "Green Aircraft" comes from. Once the colour scheme is decided, a designer at the manufacturer will mock-up some different ideas for how those colours can appear on that particular aircraft, or the principal may have a design team work with the manufacturer's design team to develop the pattern, which are called renderings.
Once the principal agrees with the paint scheme, the renderings are signed and made an integral part of the manufacturer's deliverables. Keep in mind that your basic paint job is "Matterhorn white" and "two stripes" and additional stripes, colours and shading, cost extra, and custom colours, metallic or "flip-flop" paint - where the aircraft appears to be one colour when looked at from the front and another when looked at from the back - are special orders.
A few years ago, I arrived at a manufacturer to do a paint inspection on an aircraft and, as sometimes is the case, this was the first time I'd had anything to do with this particular aircraft. All I knew about it was the serial number and the rendering, which I'd received via email the day before I arrived at that facility.
When I got there, the CAM escorted me into the hangar, to the aircraft with that particular serial number on it. Other than the serial number, however, nothing matched the renderings. The paint was completely wrong: white and blue when it should have been silver and red.
Before panic set in, I went through the documentation, looking for any Change Orders that may have been requested since the renderings were approved. Change Orders are exactly what they sound like they might be: a change in the original request, ordered by the principal. In aviation, Change Orders are more common than you might expect: logos, colours and branding changes can happen (and do happen) at anytime and when those changes are company wide, they always impact the corporate jet, too.
With no Change Orders to be found, a final check with the principal confirmed the paint scheme was as per the rendering I'd been sent.
This story gets worse.
The interior, which I hadn't been sent to inspect, was not the interior this principal was expecting.
As it turned out, the specs for this serial number had been swapped out with the specs of another aircraft which hadn't even begun to be built. The manufacturer, after looking at the options, delivered the aircraft with a later serial number than expected and that came with a delivery target that was moved out by three months.
What You See Isn't Always What You Get
Sometimes an aircraft will play tricks with your eyes when you're trying to compare one side with the other. Sometimes shading has been added to the registration marks on one side and forgotten on the other. Or italics on one side and not on the other. Because of this, renderings are the Bible of paint inspections. But what you see in the renderings isn't always what you get on the aircraft.
The third parties - and manufacturers - who paint business jets are much better at delivering a durable, beautiful, finished product with a good lifespan than what they used to be. In fact, I'd say that they've made leaps and bounds in streamlining their paint processes. This means the finished product can be excellent, with fewer drips, over-sprays and striping errors than what we used to see.
There are still uncontrollable circumstances which can effect the quality of the paint, such as high heat and high humidity. However, the advancements that have been made, for the most part, means greater efficiency and fewer re-works. That, in turn, means it's easier to reach milestones and delivery dates, which is something that everyone in aviation wants.