Radioactive Lenses : LUSENET : Large format photography : One Thread

For what its worth... There have been several questions about older lenses with glass containing radioactive constituents (e.g., thorium and lanthanum) used to improve index of refraction properties. The concern promtped me to put a question to the Health Physics Society's "Ask an Expert" forum. Their response is given in:

Hope this helps others understand the issues and risks.

Dave Erb

-- Dave Erb (, November 12, 2001


I can't find the answer on the web address you gave, however I would be interested to know if there has ever been one photographer who developed any sort of problems directly related to the use of lenses with thorium or lanthanum glass elements. I certainly never heard of one or read of one. On the other hand, if there is enough radiation to glow brightly in the dark, it might eliminate the need for fill flash.


-- Doug Paramore (, November 12, 2001.

I had no problem using the URL above to read the response. However, I did remove the spurious period at the end of the line when I cut as pasted the address into my browser.

-- Christopher Campbell (, November 12, 2001.

Interesting note at the end of that piece on uranium toners. For the darkroom worker who likes to live on the edge, there are recipes at:

Don't forget to wear your lead apron.

-- David Goldfarb (, November 12, 2001.

The following website provides a lot of interesting information about radioactivity and lenses:


J. P. Mose

-- J. P. Mose (, November 13, 2001.

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