Means of measurement and size classification

The International System of Units

The International System of Units also known as the metric system or SI is today the most widely used system of measurement in the world.

It defines precise units used to measure different physical elements such as length expressed in metres mass expressed in kilograms and time expressed in seconds. 

This system is based on decimal logic which makes calculations conversions and comparisons between different values easier.

It therefore provides greater coherence in scientific technical and industrial exchanges on an international scale.

However although this system is used in most technical and scientific fields it is not always intuitive nor directly applied in everyday life.

Some units although exact from a scientific point of view lose their clarity in common use.

For example a simple one litre bottle of water corresponds in the International System to a volume of 0.001 cubic metre. 

This value is correct but remains abstract for most people who prefer to refer to more concrete units adapted to daily experience.

The counting system and its origins

Our current way of counting is based on a decimal system organised in base 10.

This base was adopted among other reasons for its ease of use and its correspondence with the human body since we have ten fingers for counting. 

It also facilitates mathematical operations because multiplying or dividing by 10 by 100 or by 1 000 simply involves moving the decimal point.

Yet this system was not always the only one in use.

In the past other counting methods existed in particular counting in base 12 known as the duodecimal system. 

This system had certain advantages especially for sharing and dividing into equal parts because 12 is a number that is more easily divisible than 10.

Survivals of the base 12 system

In France some remnants of this base 12 system are still visible in everyday life.

Eggs are often sold by half dozen or by the dozen. 

Oysters are offered by two or three dozen. 

In more specialised fields such as jewellery making or precision craftsmanship jewellers saw blades are still sold in packs of 144 units and some beads are packaged in batches of 144 or even 1 440 units.

This persistence shows that base 12 although ancient retains a certain relevance in very specific contexts particularly when dealing with small objects produced or used in large quantities.

The notion of the gross

The notion of the gross inherited from the Middle Ages corresponds to 144 units that is twelve times twelve.

This measure was once commonly used for the trade of small objects produced in large numbers such as nails pins or certain fine tools.

Even today it remains present in some specialised craft fields notably for the sale of jewellers saw blades.

It is on this ancient system both historical and practical that we have chosen to build our own size classification system directly linked to our miniature practice.

The choice of a unit suited to miniature work

In the context of working with very small objects it was necessary to define a reference unit adapted to miniature scale. We chose one tenth of a millimetre that is 0.1 mm as the base unit.

This measurement provides sufficient precision to differentiate sizes while remaining measurable with tools accessible in the workshop.

The maximum size of our classification was set at the value of the gross that is 14.4 centimetres.

This dimension corresponds to 144 millimetres and therefore to 1 440 tenths of a millimetre. 

It forms the starting point of the entire classification.

The method of division and the logic of sizes

From this maximum dimension we established a series of sizes by progressively dividing this value in order to obtain different categories suited to miniature objects.

These divisions were chosen according to a logic that is both mathematical and practical in order to create a coherent readable and easily memorised sequence.
The resulting numbers namely 1, 2, 4, 8, 12, 24 and 72 thus serve not only as division values but also as names used to designate the different sizes.

This choice makes it possible to directly link the size designation to a precise numerical reference while maintaining a connection with ancient counting systems.

Description of each size

Size 1 corresponds to objects whose maximum dimension does not exceed 14.4 centimetres.
Size 2 concerns objects smaller than 7.2 centimetres.
Size 4 applies to objects measuring less than 3.6 centimetres.
Size 8 groups objects measuring less than 1.8 centimetres.
Size 12 is reserved for elements whose dimension is less than 1.2 centimetres.
Size 24 corresponds to objects not exceeding 0.6 centimetre.
Size 72 finally designates extremely small objects measuring less than 0.2 centimetre that is less than 2 millimetres.