Early colour measurement applications tackled both simple and complex objects
Automotive and Decorative coatings soon benefitted from the invention of reliable Colour Measurement Devices and have by and large retained the same protocols for the last 60 years. Recent inventions in that sector enhance rather than reform older practices.
On the complex side, Textile and Clothing manufacturers have continued to improve “Right first-time” colour prediction and colour quality measurement, despite the multiple ways in which fibres and fabrics are created, with very different types of chemistry, textures, and end-use requirements to be considered.
Between the two, the Colour Instrument Industry has gained vast experience in dealing with difficult objects.
Colour Measurement Instruments are designed to emulate human perception as closely as possible, and this is globally governed by the CIE for uniformity and standards. As Instruments lack “Opinion” in colour comparison, an objective response is possible, especially when two sides have opposite views.
You will often hear quality managers and colourists’ saying that they don’t “see” the same judgement as the Instruments report, and that is the exact point. A human will see a red traffic light as green based on considerations that override their visual perception, while an instrument, set to measure only under agreed and controlled “Conditions” or settings returns accurate and repeatable results free of “opinion”.
The recent and now strong trend towards more natural foods, more plant-based ingredients, and the limitation of food colourants to a very small selection of “natural” products, retail is increasingly looking for higher “Appearance” quality standards than ever before.
This is a contradiction in as much as retailers and consumers demand more and more continuity, while at the same time demanding natural untampered products. This reminds me of a clothing retailer some years back asking for a “repeatable” crease in shirts, to usher in the more casual “casual” look.
From R&D (Hybridisation) through process control to QA of produce and packaging, food can be managed for uniformity, even if the products themselves are not.
The trick is to have versatile instruments, as well as suitable instruments for the job.
The first requirement is to use an Instrument that can manage all forms of objects: Solids, grains, powders, pastes, and liquids with reliable accessories for repeatable results.
In this regard, Konica Minolta has a unique set of options, allowing our customers to select the best tools for their application, not the one that serves the supplier best.
It may be that two different types of instrument may be required for the whole manufacturing process, so we should not confuse versatility with “One size fits all”.
Let’s look at some applications:
A large food area is colour grading of flour for cake and bread application.
The object is a fine powder, which needs to be “graded” to a particular colour (Amongst other criteria) quickly and reliably.
Konica Minolta supplies a Food Grade Spectrophotometer, with an accompanying Colorimeter, both of which return the same values for the same colour, the Colorimeter being cheaper and designed for in-factory use, while the Spectrophotometer is set R&D as well.
Using specially designed glass cells, flour samples can be quickly measured and automatically graded.
If the company at the same time makes beverages, fruit pulps and biscuits or crackers, all can be measured in the opaque or translucent form (Tea). Packaging and raw materials can also be added to the list.
The most ubiquitous Colorimeter, the CR-400 series is still the most sold instrument for rapid raw materials measurement with simple accessories to measure goods directly as they arrive.
So choice if the instrument is critical, depending on the application.
Sample preparation and measurement technique is also critical.
Non-homogeneous materials can better be measured using average values. “Salt and Pepper” mixtures, as experienced in the spice industry, can be reliably measured by using an average of a number of readings.
Imagine that you can take a 40/60 blend of ingredients and take an average of say 12 readings. If you set this average value as a “Target” and then measure sample mixes, it will easily discern between say a 35/65 or 45/55 blend.
Our food-grade instruments also allow for small object measurement, through to large paste and granules options.
By combining the correct instrument, accessories, and measuring techniques, we can solve all the challenges of “Natural” and reliable colour requirements from farm to fork.