Stamps (National Trust)

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Stamps (National Trust)
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In ordinary, visible light all these stamps look like they are printed on ordinary adhesive-backed paper. Put this collection under the UV tube though, and you’ll see that the special edition National Trust stamp contains a band of fluorescent green ink. Fluorescent and phosphorescent inks are often used in ‘security printing’ on banknotes and postage stamps to prevent forgery, tampering and counterfeiting, and to help with the identification of different classes of mail. 

The Welsh and English standard Queen’s head stamps fluoresce a brilliant blue-white. In this instance, however, it’s the paper, not the ink, which fluoresces. These fluorescent papers have been brightened during manufacturing by the addition of an optical brightener; a dye that absorbs light in the ultraviolet region of the electromagnetic spectrum and re-emits it in the blue region. These optical brighteners are also found in household detergents like washing powder; practically all white clothes now fluoresce a vibrant blue under UV light. 

Sample ID: 382

Particularities

State
Solid | Object
Compound
Selections
Categories
Composite | Polymer | Vegetable
Curiosities
Fluorescent
Relationships
Adhesive | Fluorescent | Ink | National | Optical Brightener | Paper | Security | Stamp | Standardised

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