Tips on Stamp Collecting

Giori printing

Recess-printing

Printing with plates is a recess-printing process. This means that the lines and patterns are engraved into the plate. A good example of this technique is an etch.

Intaglio printing plate

There are two ways to make a printing plate:

Mechanical

Acid etching

The printing-plate is thin and therefor flexible. The chromed printing plates can be placed on the roller-press.

Intaglio printing

Rolls bring the treacle ink on the plate. The whole plate will be covered with ink. A system of wipers removes the surplus ink from the plate. Paper is transported between the printing-plate and the pressure roller. This is processed under high pressure. The ink will only partly be absorbed by the paper. Small sections will reside on the paper and cause ridges. In most cases you can feel these ridges on a stamp with your fingertip.

More colors

Mostly intaglio-printing is used to print in one color. The enormous force caused by the pressure roller effects the paper: some parts will be expanded while other parts do not. Printing colors fit badly when these small differences of format occur. This is the reason why stencil rollers are used when printing is done with more than one color. In consequence printing in more colors is possible with the use of only one printing plate.
This process is especially used in France and Spain, but has also been used in The Netherlands sometimes:

Red Cross, 1953.

K.L.M., 1959.

Marines, 1965.

I.L.O., 1969.

Italian castle-issue

Some of the stamps of the Italian castle-issue (1980) are printed with the giori method too:

500 L (Mi.1719). Three colors: blue, green and brown.

1000 L (Mi.1724). At first the color orange was printed in lithography then followed by three colors (blue, green and black) giori printing.

Stencil rollers

The surface of the roller is cut in such a way that only the printing areas remain. This has to be done for each color separately. For each color an ink-roller has to be made.

The giori printing process

Only the not removed surface of the ink-rollers transfers ink to the printing plate. In fact: The rollers stamp the plate.
Through the process of stamping the plate several times a colorful print is made.
Good tuning of the rollers is important, while the rollers replace multiple plates in this process.
In Dutch literature this technique is called giori process, named after the Giori press on which Dutch plate printed stamps are manufactured.

Recognition

Printed by plates. Recognisable on the relief and the fact that the colors are printed beside each other.
The colors are not always printed on the same position: Sometimes they overlap, sometimes they are printed far apart.