March 2005 Design Tip

The Cost of colour

Henry Ford famously offered cars in “any colour…so long as it’s black.” His focus was on efficient production and low cost, and custom paint had no place in his production line. At Protomold, we’re all for efficiency and low cost, but we’re more flexible than Ford was. colour, however, can still be an issue.

The base colour of most resins is either black or an array of lighter shades ranging from clear to brown and generically referred to as “natural.” This is why so many moulded plastic products appear in those colours. But if you want colour, there are several options available.

  • Perhaps the simplest is paint. Not all plastics can be painted, but for those that can (and that will not be handled in such a way as to damage the painted surface) there is a huge variety of colours available. Painting is a separate process from moulding and is not a Protomold offering.
  • The simplest and least expensive way of getting colour into (as opposed to onto) the resin is stock colourant like Omnicolour, whose palette can viewed here. Protomold stocks about 40 of the 100 available colours. The rest can be had at modest cost and can take up to four weeks for delivery. The final colour can be skewed by the tint of the base resin, and because the colour is blended in the moulding machinery, the final product can show swirls and significant colour variation.
  • Standard pre-coloured resins are available from resin manufacturers in a wide variety of colours. These are quite consistent in shade, but have lead times of four to eight weeks. They typically must be ordered in minimum batches of up to 4500 pounds and must be supplied to Protomold by the customer.
  • Custom-coloured resins can be precisely matched to a customer sample by vendors like RTP ( or GE colorXpress ( Protomold customers should deal directly with the supplier to obtain the necessary resin. Costs vary and lead times are typically two to four weeks.

Finally, a note on metallic colours. Protomold can work with customer-supplied metallic resins, but these can cause cosmetic problems when the suspended metal flakes orient themselves along flow lines in the moulded part. A better solution for achieving metallic colours may be applying metallic colour paint.

CORRECTION : The animation in last month's Design Tip incorrectly showed the A & B sides of the mould. This has been corrected.