Contour Comparator

These use a disc or a chart with coloured panels, each labelled with a figure. Normally, tablet reagents are added to the sample and the colour that develops is matched to a panel on the chart or disc. View visual test methods here.

Test Strips also use the principle of colour matching.  The reagents are already present on the test strip.  You simply dip them in the sample and compare the colour to a chart on the container.

The discs used in our Contour Comparator kits are produced from fade-free acetate and inks.  The colour acetate petal discs are designed to be accurate for 10 years, providing they are stored in a cool, dark place.  Continuous exposure to intense UV light sources (such as daylight) may cause premature colour fading.  The outer clear plastic casing can become blemished or stained if exposed to solvents, chemical reagents or abrasive surfaces and affect the result.

The reasons for carrying out a test, the situation and the application all effect the choice of what test method is best for you.

For example, whilst accuracy and repeatability might be the most important factors in a modern laboratory.  Weight, speed of test, and the lack of requirement for electricity might be more important in a field expedition.