Hi

Opaque Liquids are impenetrable by light and are best measured using Directional 45/0° reflectance geometry. This is the geometry that most closely matches how the human eye 'sees' colour.

Translucent Liquids allow light to pass through, but only diffusely, so that objects on the other side cannot be clearly distinguished. Both reflective and transmittance measurement modes may work well depending on the translucency of the sample. 

Transparent Liquids allow light to pass through with little or no interruption or distortion so that objects on the other side can be clearly seen. These liquids can only be measured using transmission instrumentation.

- Polymer Colour Measurement

Synthetic and natural polymers play an essential role in everyday life. Natural polymeric materials include shellac, amber, wool, silk and natural rubber, while the list of synthetic polymers includes synthetic rubber, phenol formaldehyde resin, neoprene, nylon, polyvinyl chloride, polystyrene, polyethylene, polypropylene, polyacrylonitrile, PVB, silicone, and many more. Polymers can be transparent to translucent, and are preferably measured using a transmittance instrument. However if you also measure opaque samples, you may prefer to select an instrument that measures in both transmittance and reflectance mode.