Back-to-basics: adding colour to plastics

Colours and special effects are key ingredients of plastics compounds, offering countless possibilities to designers who want to differentiate their products. Colorant suppliers sell their pigments and dyes primarily to compound and masterbatch producers, although a small volume goes directly to processors of finished parts. Jennifer Markarian reviews some of the basics, including types of colorants and special effects, how they are added to compounds and masterbatches, and concerns for adding them at the processing line.