Re: Dose to fog camera film

["John Moulder" <jmoulder@post.its.mcw.edu>]

> I looked it up in QUEST  (another nifty HP 
> tool) and found the reference :  Shuping, R  "Use of Photographic Film 
> to Estimate Exposure Near TMI"  HP July 1981  41(1) pgs 195-9. 
> Similar research results may appear elsewhere.  

> J. P. Davis  (my own opinion only) 
> joyced@dnfsb.gov 

Thank you Joyce.

That HP article has the answer.
1) Two of the major isotopes released at both TMI and Chernobyl are ideal for 
fogging film:  Xe-133 and I-131.
2) With a densitometer and 400 ASA color film the authors were able to show 
that they could detect a dose as low as 8 mR
3) Other film (B&W or lower ASA) would be less sensitive, but even by eye it 
would appear that exposure above 200 mR would fog most film badly enough to be 
evident to any amateur photographer.

Therefore, a dose from TMI as high as 1000 mrem over areas of significant 
population would require every photographer and photoshop within about 20 
miles to be in on the conspiracy (plus every medical professional with an x-
ray machine or a film badge).  A dose of 25 rem over the population close to 
the plant would have fogged every piece of film within several hundred miles.


John Moulder (jmoulder@its.mcw.edu)