Influence of light on the shade

1. The spectral colours of sunlight

All objects and bodies of our environment are present in many different shades. The reason for this colourfulness can be traced back to the characteristics of light and the chemical composition of the substances of which the objects are made. Every perception of a shade can be traced back principally to four factors:
source of light, illuminated object, eye and consciousness.

If a ray of white light is aimed at a prism, a broad band of different colours emerges. This colour array is called the visible spectrum and was discovered by Isaac Newton around 1700.

Furthermore light can be described physically as electro-magnetic wave (Unit: Nanometers = nm).
The human eye is only able to perceive a range of wavelength from 400 - 750 nm. Different wavelengths induce the feeling for different shades. You can measure shades also by frequency. Valid is: The longer the wave, the lower the frequency.

2. Mixture of colours

The basic colours are yellow, magenta and cyan, which are so-called pigment-colours. If you mix them together, they change their light-brightness and cause darker shades.

An example of this are the colours, that you are mixing, e.g. paints.

Origin of stamps

Stamps and their predecessors, seals and signets, have been around for longer than paper itself. Before papyrus, seals were used for identifying ownership. Brickmakers impressed their stamp into their bricks; carved wooden shapes were used to press images into wet clay tablets.

The earliest personal "marking device" was the amulet (or "charm") on which magical signs were engraved. It was believed that the amulet's impression in clay, possessed the charm's original magical powers.

Herodotus "Father of History", tells us that every Babylonian carried a signet stone: one could believe that "personal tokens" were as important in ancient Babylon as in today's consumer society.

Later, the use of stamps and seals became more selective and they were regarded as tokens of power and social standing.

In the Middle Ages the use of seals was restricted to Emperors and Kings; then extended to Bishops and the Nobility.

Eventually, Guilds and Patricians enjoyed the privilege of using stamp or seal. From the seal, the stamp was developed.

Nowadays stamps are self-evident for everybody again. Every company needs one and in some countries, e.g. China a stamp counts more than a personal signature.

The range of stamps exists from wood, to synthetic, to metal, to pagination, to self-inkers up to microstamps.

As the different stamps and stamp machines evolved as well as various applications, this resulted in numerous stamp pad inks being developed.