Phosphor Bands

Phosphor bands: are visible bands of phosphor ink printed over the stamp design, these can be seen with the naked eye when viewed flat and held up to the light at eye level. They were first introduced during the 1950s on the Wilding series.

When viewed under a ultra violet light, either short wave for old phosphor or long wave for issues after 1993, they give off various degrees of fluorescence and phosphorescence (afterglow).

Old phosphor : B

Most early machins have this type of phosphor they consisted of either a centre band, two side bands, or a single side band. These were either green or blue in colour.

New Phosphor : A

A phosphor was brought into use in the mid 1980s, it is a variation of the phosphor used on the AOP paper issues (see phosphor coated paper )The bands on these stamps fluoresce a little fainter than the previous printings, and are violet in colour.

C Phosphor :

This phosphor had a additive called cartax mixed with the phosphor ink. This in turn allowed the stamps to fluoresce a yellow green colour when viewed under long wave ultra violet light. This is also termed AY phosphor by some specialist groups.

Early printings of this type were the 18p value printed by Enschede in 1991. Several trials were carried out with various amounts of phosphor ink overprinted, this in turn resulted in several variations of yellow colour in the fluorescence. All these variations are catalogued and are all collectable.

A2 Phosphor (afterglow)

A trial printing was released, this was termed novaglow by the printers in 1994, the trial run consisted of 38p values (again printed by Enschede. These stamps had a blue or light violet afterglow, this can be detected when viewed in a dark room under a long wave UV lamp, switch the light off for the desired effect.

Other denominations soon followed, some included a layer of varnish under the phosphor ink, this was either 2 mm or 4 mm wide (more about varnish later ).

More stamps with a blue fluorescence have since been issued and it now seems to be the norm on all of the current issues.

Width and length of Phosphors :

As mentioned above all stamps of this type have either one or two bands running vertical from top to bottom of the perforations. Some have extra bands or no bands these were printed in error, and are very collectable.

First class stamps printed in sheets normally have two 9 mm bands these are set each side of the stamp. The 10p stamp printed on the Chambon press is a exception to the rule having 10 mm bands.

Second class stamps from sheets have one 4.5mm centre band ,or on some more recent issues a 4 mm or 5 mm band.

Varnish under the bands :

Some of the stamps printed by Enschede have a varnish strip printed under the phosphor ink.These were applied to eradicate problems, with the paper being to absorbent, this in turn caused the phosphor to have a weak signal. Two widths of varnish were tried, first a 4 mm varnish then later a 2 mm version. Both varieties are collectable although the 2 mm type is hard to distinguish as the layer tends to correspond with the inter stamp margins.

To view these varnished bands they must be held up to the light at a slight angle, the varnish seems to be a little lighter than the actual phosphor ink that has no varnish below.        Next Variations