It is possible to test an enlarging lens for significant damage by looking at fine (fine!) lines in the image. If the lens is compromised black lines against a light background will come out wider than they should. And white lines against a dark background will come out narrower.
The effect is caused by subtle lens flare that manifests long before actual lens sharpness and resolution start to degrade.
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The word Photography first uttered and defined by its author Sir John Herschel at Somerset House, London on the evening of March 14, 1839: quote "Photography or the application of the Chemical rays of light to the purpose of pictorial representation" unquote.
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