PEFTEC - Abstract

Abstract Information :

Color Measurement – it’s more than just aesthetics

This presentation provides an introduction to the importance of colour measurement in the industry, explaining why we need to measure colour and an introduction to the varying color scales currently in use in these industries.

Defining the colour of product and ensuring colour accuracy every time is critical to long-term success. Reliable and repeatable colour test results are key to ensuring final product quality and minimising production costs. The speed of analysis is also vital for efficient process control.  Simplicity of operation helps reduce error and increase productivity.

Obviously, we all know what colour is and are all experts in its definition. However, the human visual system is very imprecise when it comes to both judging and defining the colour of objects. There are several reasons for this:

The environment plays a considerable part in our assessment. Even in the physical environment where we live, different lighting affects how a colour is assessed. Consider the extreme examples of street lighting vs. daylight; a sunny day vs. a dark office…colour perception changes.

Humans are not machines. We tend to suffer from fatigue, poor colour memory (ask any policeman) and visual defects. Our vision is strongly affected by background effects (colour viewed over-black looks different to over-white) and colours viewed cannot be “stored” for future reference.

Colour communication between humans relies on non-exact verbal descriptions – we describe as “too pink”, “lighter”, “darker”, “needs more ‘zing’”. These are unclear descriptions and subject to variable opinions.

In essence we are subjective in our evaluation of colour and visual assessment with the eye is unreliable.

Using electronic instruments, colour communication is objective and independent. Instrument readings are accurate, reliable and consistent and can be measured, stored and recalled. Light source, surface and the human observer can all be quantified allowing clear objective assessment.

Colour co-ordinates (such as CIEL*a*b*, CIEL*C*h*, XYZ), Colour Scales (ASTM, Gardner, Hazen, Saybolt) and spectral data allow exact standards to be communicated. There is no reliance on old and faded physical samples and rough estimates that result in painful (and expensive) miscommunications.

Agreed tolerances make pass/fail decisions clear and easy:

Precise standards and acceptable variations can be agreed internally with suppliers and customers. Mutually-decided Standards ensure both parties adhere to the agreed Standard/Tolerance and costly rejects are minimized. Numbers, not opinions, count.

Using spectrophotometers, standards and samples can be stored, with zero change forever:

Complete records can be kept, data reviewed and trends monitored, hence wasteful mistakes will not be repeated and integrity of production is insured. An automatic spectrophotometer should be considered for each of the following:

1. External Quality Control of incoming and outgoing raw materials and products.
2. Internal Quality Control of production ensuring compliant product and minimizing costly material and time wastage.
3. Continual Monitoring, in real time, of production processes.
4. Faster matching of customers’ colours. No more time ‘guestimates’
5. Clear Communication ensures exact definitions. Customer standards can be made and agreed upon – eliminating miscommunication and unfortunate “negotiations” over poor colour compliance.
6. Time + Wasted Materials = £££££’s. How much are you really wasting?
7. Research and Development is totally objective - the researcher cannot bias the interpretation of results.