What is the value of colour measurement?

Accurate colour measurement, or any light based test for that matter, is a lot cheaper than many traditional testing methods, particularly as its non destructive. It is however not free. So when is colour measurement essential?

Lets take a typical Industrial Example - Auto manufacturing - Quality

Car makers tend to have very high standards, obtain parts from many different suppliers around the world, made of multiple materials with varying functionality. It is not possible to start matching doors to bodies, bumpers to bonnets and other accessories like plastic wheel trims and petrol caps on the assembly line. One of the many technical specifications include a colour specification. To be accurate and universal, the specification include about 14 rules to ensure that the different parts match well under various conditions. The cost of using Spectrophotometers far outways reprocessing of cars on the assembly line, as well as the possibility of a reduced quality perception by customers. The same approach also applies to the colour of the tail lights, the intensity of the headlamps and dashboard icon clarity. 

Example - Fashion Plastics - Branding and Formulation

Fast Moving Consumer Goods (FMCG's) run to very tight time constraints. Lets say a well known brand name is going to launch a new skin care product for a high selling season like Christmas. It can take plastic container manufacturers months to get the packaging approved working visually with physical samples.

Today, a designer can post a master colour on line, and by using a Spectrophotometer with Colour Prediction Software actually formulate the plastic colour within days. Packaging, either paper or plastic, can be married to all the related media according to master colour details. This results in lots of savings as well.

Example - Textiles - Matching Fabrics - Quality

Fashion is created at high speed and the market reacts very rapidly as well. While some garments might be OK with it, mostly we would like the left sleeve or leg to match the right sleeve or leg, even when these come from different rolls of fabric, maybe over months of delivery. Spectrophotometric's make this easy, speeding up fashion and eliminating defects.

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What is Colour Difference Measurement

What are we actually doing when we measure colour? To understand this, we need to understand what our actual objective is:

• Compare one colour to another
• Obtain actual colour data 
• Predict a colour formulation
  
  This post will deal with the first task only.

Compare one colour to another

Colour Comparison is usually the first and simplest task to carry out.

There are many reasons WHY we want to compare colours, like batch to batch colour continuity, quality control or to ensure one part of an assembly matches another, say in the auto industry. Colour Comparison can also be useful for Color Grading like with Flour, Fruits and Fruit Juices etc.

We have done this visually since the first time colour continuity was important. Perhaps an ancient potter or carpet weaver saw this need.

As soon as we compare colour visually, we run into a number of problems. The first is, do two people agree on the comparison, due to possible colour perception defects in one or the other observer. The next problem is, the colour seems to change at different times of day, in different physical settings. Following from this, are two observers able to agree (An opinion) on a colour. Often a supplier and a customer have different expectations which "Colour" their opinions. (Seeing red as the saying goes!)

It soon becomes clear that we need a stable reliable device that can "See" colours like humans do, and relate the data without any judgement or opinion. Enter the Spectrophotometer or Chroma meter (Colorimeter).

Studies into HOW we perceive colour reveal that the perception (In the brain) is influenced by a number of factors:

• Illuminant Source (natural, artificial)
• Size of object
• Angle of observation
• Amount of data observed
• Proximity of the object to other objects of other colours

There are about 14 "Contextual" influences on colour perception comparison, which will be dealt with in more detail in future posts, but the conclusion is that the perception of colour varies, and can not be said to be a property of an object like say weight or dimensions, but are subject to the Contextual Conditions" under which the observation was made.

To this end, the CIE (International Commission on Illumination) an international body regulating standards, prescribe the various contextual specifications in detail.

In this post, let us assume that we are comparing two colours using one CIE certificated Spectrophotometer with a known setup and using a known CIE approved Colour Space Equation (Say L*a*b)

• Prepare an object for measurement
• Measure the object
• The instrument will return L*a*b values.

These values are almost meaningless to the observer, as it is very difficult to envisage what could has been measured from the values returned. In many cases however, Quality Assurance people who are number fixated WILL look at this number, and then compare it to a "Correct" number on record. IF (Huge IF) the values were obtained UNDER THE SAME CONTEXTUAL CONDITIONS, you may infer that the numbers are close or far, but what does the difference between one number and another visually mean? If you think you will get the same numbers measurement to measurement, its a fantasy. Thats not how this works.

The quick solution to Number Madness is to use a "Target" and "Sample" approach.

A Target will be the master colour you wish to achieve, and the Sample colour will be the current batch etc.

If you measure BOTH the Target (Known wanted colour) and the Sample at the same time under the same contextual settings, you can then expect to have some sane method of comparison. The CIE L*a*b standard also come with a Colour Difference equation known as Delta ( ∆ ) L*a*b.

If you set the Instrument or software to give a Colour Difference reading, you can then see what the implication of the differences may be.

So L =  Darkness (Black = 0) or Whiteness (White = 100)

   *a  =  Redness in the + side or Greenness in the - side. The numbers indicate the INTENSITY of redness    
            or greenness.

   *b =   Yellowness on the + side and Blueness on the - side, and the numbers the intensity as for *a

By comparing the DIFFERENCE between a Target and Sample, and by reducing the difference to an AVERAGE of the difference of Target to Sample you will end up with a single value say ∆ 1.5 . This is now a meaningful number. For instance a difference of 3 is clearly visible to the human eye, and 0.5 is hard to tell.

Future Posts will cover more detail, and you can looke now at the advanced information here

Colour Measurement and Eskom "Load Shedding"

South Africans will know that Load Shedding is our local quaint name for planned unplanned power failures. How does this effect you?

If you are a user of our Konica Minolta CM3600d or A Series Bench Tops or the Konica Minolta CM-5 Bench top spectrophotometers, how does this affect you?

Typically, if a PC and software is involved, surge protection and a UPS system will be required in any case. The CM-5 range however can work as stand alone models using their own firmware, but again as they are mains powered, a UPS system is recommended. This is more to protect the instrument from power surges than anything else, as UPS system are expensive and their useable working time is often quite short.

As it seems that the power issue is here for quite some time, we have another option: Both Bench Top Instrument types have portable hand held versions as well, which run on batteries. Contrary to what some may believe, the quality of these portables are of the highest standard, with specifications similar to that of their bench top versions. You can confirm both the CM3600d and CM-5 portable version specifications by comparing the catalogues of both versions.

The number of estimated measurements on battery is quite good, well enough for the two hour load shedding periods. An AC mains adaptor is also available for the portables should you wish to save a bit on battery life during normal power supply hours.

We have a number of customers who happily mix Bench Top and Portable in the same circle of application, and you have the added benefit of Field (At the customer) measurements as well.

Meat and Colour. Is Red the only Game in Town?

A lot has been said and written about the artificial colouring of meat either by some chemical treatment or trick lighting at the point of sale. While certain colourant's can be measured and tracked by their colour characteristics, and even light sources screened for "Unfair" or  "Flattering" lighting (Imagine if Hollywood was not allowed to cheat!) there are many more things Spectroscopy can do to evaluate or categorise output from your local butcher.

It has long been known that the composition of animal feeds can affect the colour of meat, which in turn can have a relationship with fat content, the type of fat content, and eventually health and even flavour outcomes.


Dr Cobus Ferreira completed a study in 2014 which demonstrates these assumptions, particularly with relation to Pork meat. it was found that Pork quality can be improved upon when using a natural feed additive CLA (Conjugated linoleic acid).

Details of the study cane be found here.Study details

You will notice that colour measurements were carried out with our Konica Minolta Chroma Meter CR400.

This instrument is one of the most used colour measurement devices in food research, partly due to its accuracy, reliability and affordability. Backward compatibility for 20 years also makes this model a very valuable research tool.




 

Colour Grading of Grain Flour - Wheat

A number of professions claim old age in their pedigree, but few have a better claim than Wheat Millers. Since farming crops became one of the first global addictions, bread flours have been milled to create flavour, texture, quality and ascetic appearance.

While today a minute portion of the crop is milled by Artisan Bakers, the vast majority globally is milled by large industrial groups using similar processes and equipment.

Like Fish, Bread whiteness increases the value of flour based baked products, but there is an industrial equation of time versus whiteness which has to be balanced. Added to this, over milling reduces the food value of flour.

In the 1950's scientists began to use Spectroscopy to try and standardise flour grades. The theory was good, but in practice, instruments were unreliable, the measurement fiddly and inter-instrument agreement near impossible.

This gave birth to the so called "Ring Test" where batches from various sources could be correlated to a "Known" standard (Actually and arbitrarily selected standard) and the various batch readings "Adjusted" (Corrected) accordingly. Never satisfactory, this type of procedure lasts up to the present day, although proper colour measurements have been carried out for decades by some Millers in some countries.

Some years back, South African Millers were fined for "Collusion" and while the merits of this is for another discussion, company's became weary of all using the same technology. This became the perfect time to introduce STANDARDISED rather than same systems to confirm with managements desire to be seen to be working above board.

Simply put, if millers could all use Kg to designate the weight of the packaging, the CIE L*a*b colour space norms could be used as well. A global colour standard, CIE is an independently controlled colour standard.

Years of research and tests carried out locally in South Africa validated that a mill can reliably across a number of mills, quickly and accurately grade batches to known "Standards".

To day this is a widely used accurate practice for precise and communicable colour grading data

As us for more at www.narich.co.za

Worried about the colour of the Bun in the Oven?

Baking Consistency is highly desired by Industrial Bakers, as well as my old Gran. Taste, texture and time were all critical to her, but nothing ruined her apple tart or shortbread bake was a dark sign of scorching, or worse, a pasty undercooked ghost of perfect article. So daunting was this task that my mother was reluctant to even try and compete, Enter the Industrial "Home" Bake.

Today, we can manage 100 metre long continuous ovens with process controls that both measure the colour of the bake, as well as adjust speed and temperature. Typically however these bespoke installations don't adhere to international standards.

Enter the Konica Minolta Colorimeter BC-10. 

Global food brands require consistency not over months of production, but over many plants in many countries. Globalisation offers a known version of your favourite burger any where in the world, and the price for this is standardisation.

With the BC-10, one can monitor and control the colour of baked, fried, smoked and processed foods as well as ingredients in various environments to ensure consistency in appearance. It is the ideal solution for multi-plant, multi-lined companies, co-packers and restaurant chains that seek enhanced consistency and quality of their products' appearance.

Besides the crust colour, the BC-10 measures colour on all kind of bakery and snack food products, yeast, brown sugar, calcium propionate, and flour blending.

The BC-10 is very simple to use, compact and light-weight, battery-operated and can display the measured values in Baking Contrast Units (BCU), a standard grading scale in the baking industry, or classic CIELAB colour values.

Ask us to Tell me more about the KM BC 10

Hey Farmers - What's Colour have to do with your Crop?

Farmers more than anyone feel the pressure to improve their farming methods more than ever before.

Larger farms, less labour, increased productivity, reduced prices and green sustainable practices seem to be a set of contradictions that can be resolved.

Soon after the widespread introduction of fertilisers, it became clear that less is more, because more was running over as excess into water systems, rivers and reticulation plants. But how much fertiliser is the correct amount.

Scientists were able to calculate how much of a particular chemical was the correct dose for a particular crop under laboratory conditions, but what about on the actual farm. Soon Chemical Mapping became a necessary tool to understand the ever varying land, even on a single modest farm.

Further research found a direct link between Chlorophyll content in the plant and its health. By measuring the RVI or Ratio Vegetative Index, plant leaf health can be determined. Part of the determination is a lack of Nitrates.

With this information, and a chemical map of the land, as well as the known properties of the actual fertiliser being used. it is possible to manage accurate dosage quickly, reliably and efficiently.

 

The Konica Minolta Chlorophyll Meter SPAD-502 Plus is the local Benchmark for this application, and is our most sold colour measurement instrument. used by farmers, fertiliser manufacturers and crop researchers the SPAD 502 is a rapid reliable and rugged tool for both field and laboratory work.

 

 

Sold, supported and serviced by Narich (Pty) Ltd, you can be sure of optimum farming at all times.