There are several methods for colouring polymers, each with advantages and disadvantages. Dry colour involves mixing pigments directly into the polymer but can be messy and inconsistent. Masterbatch uses a high concentration of pigments compounded with a carrier polymer for better dispersion. Liquid colour is similar but uses a liquid carrier. Fully compounded colour extrudes the pigments with the base polymer for the most accurate and controlled colours. The appropriate colouring method depends on factors like required colour consistency, flexibility, and impact on material properties.

1. Colour Technology

2. Why use Colours? Identification Branding Convey a Mood or a Style Choice

5. Human Visual System

7. The Rods and Cones

8. The Rods and Cones 5 million per eye (more L and M cones than S cones) 100 million per eye Responsible for daylight (photopic) vision Responsible for low- level (scotopic) vision Cone function Rod function scotopic mesopic photopic luminance Cones Rods

17. Colour

19. Colour Space + L = Lightness - L* = Darkness + a* = Redness - a* = Greeness + b* = Yellowness - b* = Blueness +a* +b* -a* -b* L*=100 L*=0 L* L* -a* +a* -b* +b*

20. Colour Space - Delta E a* b*  C*  H* is the difference between two points in colour space, often use to determine a colour tolerance or specification. S C S H

38. A Polymer for Every Application