Which is the hardest color to make? Lime green, maybe, or turquoise? Surprisingly, it’s that universal symbol of purity: white.
Because there isn’t one shade of white. “There are hundreds of shades – blue-white, yellow-white, grey-white, depending on the undertones,” explains Katie Smithson, Color and Design Team Leader. “Our eyes are very sensitive to different shades of white, so the tolerances are critical. It makes color-matching very difficult.”
Color is created by adding combinations of chemical pigments (that mimic the world’s natural color pigments) to the base formulation at the start of the powder manufacturing process. A computer works out the combinations and concentrations of different pigments needed to produce specific colors. “It can predict colors to a high degree of accuracy over a very wide range,” says Smithson. “If we’re matching a new color, we can choose the nearest approximation and then fine-tune.”
Frequently, colors are tailor made for customers, often working from samples the customer has brought in. These can vary from liquid paint samples to colored paper even to bits of bicycle. “Often the request is, ‘like this but a bit brighter or a bit different’!” laughs Smithson.
Some colors take longer than others to match, she says. “Very strong colors, such as bright yellows and reds, are difficult because the pigments are organic and break down under UV light.” The team has to find a way of achieving the color without losing performance characteristics such as durability and temperature resistance. Special effects paints, such as metallic or sparkly, are also tricky. “As they’re not solid colors, the appearance can change dramatically depending on what angle you’re looking from. It’s definitely challenging!”