Humans can typically perceive approximately 10 million different colours, though some 1 in 12 men and 1 in 200 women have come form of Colour Vision Deficiency (CVD). In western culture we can rapidly recognise and name the primary and secondary colours in the light (additive) and pigment (subtractive) colour systems. As a result we often use colours to give weight to signage:
- Red backgrounds for prohibition signs.
- Yellow backgrounds for warning signs.
- Blue backgrounds for mandatory signs.
- Green backgrounds for emergency/safety signs
or to differentiate between similar tools for different tasks:
- Red kitchen equipment is used for raw meat.
- Blue kitchen equipment is used for raw fish.
- Yellow kitchen equipment is used for cooked meats.
- Green kitchen equipment is used for salads and fruits.
- Brown kitchen equipment is used for vegetables.
- White kitchen equipment is used for dairy products.
Whilst the use of colour to differentiate between equipment is common in kitchens where cross contamination is likely, it is less likely in the food processing industry. Here, where the risk of cross contamination is reduced by process layout, the greater concern is foreign body contamination. As a result materials such as packaging, process packaging, gloves, disposable hairnets and the like are coloured blue. Why blue? – since there is little or no natural blue food having materials in this colour means that any contamination, should it occur, is very readily and visually identifiable.
The use of colour does not have to be restricted to making potential contamination readily identifiable, in processes where the product has a limited life, it can be used for batch identification and stock control. With six primary and secondary colours and several readily identifiable tertiary colours it is possible have a different coloured packaging film for each day of the week. In this way if the product should only be in the plant for 3 or 4 days it is simple to visually discern at a glance when a product was produced, which product should be used next and which products should be disposed of.
Combining print and colour
And what if the plant runs several shifts? Well, the colour range can be extended but above about seven colours it becomes more difficult to discern between some of them. The alternative is to stick with the same daily colours and to add print. If there are two shifts per day then the addition of simple black stripe would suffice to differentiate between the two. For sites with additional shifts, additional stripes can be added. Such printing does not have to be black nor does it have to be a stripe but a full length contrasting stripe is more readily visible.
Another common use for coloured films is in waste identification. In the food industry different waste streams such as rework, not for human consumption, no food waste can all be simply and readily identified by use of different colours. But it is not restricted to the food industry, other businesses can use colour to identify differing streams such as recycling, non-recycling, food and waste paper for shredding. Similarly in the veterinary and medical sectors different coloured films can be use to differentiate grades of clinical/bio-hazard waste.
In the horticultural world many products need to stored away from light, thus to aid this when storage in the dark is not guaranteed films can be coloured black opaque to minimise colour presentation.
A final typical use of colour is marketing, most businesses have a colour that is associated with their corporate branding and so it is not usual for them to seek to use that colour in their packaging and the materials that they use for their products.
Within its portfolio of products and services Hanmere has the ability to produce films with a wide range of colours and colour densities, and to print both single colour random print and six colour registered print. For customers migrating from kraft products to polythene films we can even produce film that not only feels like kraft paper but also looks like kraft paper in colour as well. For those businesses who require opaque black bags for horticultural use or blue bags for food use we can supply bi-colour films that have the internal surface one colour i.e. black or blue, and an outer surface that matches the branding requirements for the the product.
To discuss your requirements for coloured and printed films further, feel free to contact us on 01462 474777, or complete our contact form and we will contact you.
 Judd, Deane B.; Wyszecki, Günter (1975). Color in Business, Science and Industry. Wiley Series in Pure and Applied Optics (3rd ed.). New York: Wiley-Interscience. p. 388. ISBN 0-471-45212-2.