Infra Red for Back Lighting

See how White Light and Infra Red reveal Watermarks and Hidden Data

Here is a blank piece of paper (which has a watermark) and another piece with a picture of a man.

Both pieces are pasted face down on backing card.

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Result 1

Result 2

Notice that none of the black Parker ink is visible.

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Front Lighting

Unmodified—————————————————- Infra Red

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Infra Red Light Sheet with mm. scale

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