J Edgar Hoover; and 14%

[Helen B]

I may regret this, but here goes:

I was flicking though the magazines at the dentist, waiting for another root canal, and I noticed that some of the more recent magazines were only about sixty years old. Among them was one that had an article on UV fluorescence photography written by J Edgar Hoover in 1940. Another had an article about testing different grey cards to get good exposures - in 1939, though the article was published in 1940. The 'Neutrowe Gray Exposure Aid'. It is 14% grey. The article describes, in quite a lot of detail, how they arrived at 14%. It also explains something of the Weston system.

A letter appeared in a later magazine, taking J Edgar to task about some inaccuracies in his article.

I've made a couple of pdfs, including the letter, of the articles. If you would like a copy of either or both of them, send me a pm with your email address. The pdfs are over one megabyte each.

Best,
Helen

Professor Karapetoff demonstrates the use of the gray card in '39 or '40.

Dead Link Removed

 

[noseoil]

"A letter appeared in a later magazine, taking J Edgar to task about some inaccuracies in his article."

Helen, I would bet the author of that letter was a bit regretful after taking him on in an open forum. tim

 

[bob01721]

"... Professor Karapetoff demonstrates the use of the gray card in '39 or '40..."

Hmmm. When I use a gray card, it's at the subject position, oriented toward the camera. Apparently, he uses his at camera position? I'll have to try that!

 

[Lee L]

Hmmm. When I use a gray card, it's at the subject position, oriented toward the camera. Apparently, he uses his at camera position? I'll have to try that!

Bob,

As long as the card is in the same light as the subject (as seen by the camera), the reading should be good. Indoors in studio lighting the position of the card should be right where the subject is, as light falls off as the square of the distance, which is significant in studio work. In the instance shown in the attached photo, the light is essentially the same behind and in front of the camera. The gray card is only 50 ft or so closer to the sun, which is the light source and about 93 million miles away, so there's not a lot of difference due to light falloff. It also appears to be drier behind the camera.

Note that the camera on the tripod is pointed away from the viewer and the card is held in the same orientation to the sun as the landscape seen by the camera.

Lee

 

[David H. Bebbington]

. Among them was one that had an article on UV fluorescence photography written by J Edgar Hoover in 1940. Another had an article about testing different grey cards to get good exposures - in 1939, though the article was published in 1940.
]

Is this a way of getting the exposure just right to eliminate pinko radicals?

Regards,

David

 

[bob01721]

"... Indoors in studio lighting the position of the card should be right where the subject is, as light falls off as the square of the distance, which is significant in studio work. In the instance shown in the attached photo, the light is essentially the same behind and in front of the camera..."

Gotcha! Thanks! I was being facetious, but I hadn't really thought that much about it. I generally don't use a gray card outdoors -- I use either in-camera meters (35mm) or a spotmeter (LF). Indoors, with portraits and still life, I use the card as you described.

"... The gray card is only 50 ft or so closer to the sun, which is the light source and about 93 million miles away, so there's not a lot of difference due to light falloff. It also appears to be drier behind the camera..."

Quite. Ha!

 

[Lee L]

Gotcha! Thanks! I was being facetious...

I suspected as much, but couldn't quite be certain (no smilies, etc.). We've had a large number of beginners' questions about lately, so I guess I'm in that mode. Thanks for taking my reply with grace and good humor. We could use more of that.

Lee

 

[Michel Hardy-Vallée]

In the instance shown in the attached photo, the light is essentially the same behind and in front of the camera. The gray card is only 50 ft or so closer to the sun, which is the light source and about 93 million miles away, so there's not a lot of difference due to light falloff.

So that explains also why before spotmeters were common, photographers just walked closer to a tree to meter it more precisely. I could never reconcile why this works with the inverse square law. But I guess I forgot that the light source is 93M miles away!

 

[Helen B]

The magazines in question are copies of Photo Techniques from '40 and '41. That's not the same as either of the PT magazines available today. They weren't actually in the dentist's waiting room, by the way.

I found the idea that the Director of the FBI would write an article for a photo magazine interesting enough, but the writing and publication of the polite letter telling him that he was a bit sloppy with his facts struck a chord.

The letters page, on the few occasions that letters were allowed, covers the same old things. There was a discussion about whether or not short focal length lenses can be said to have more depth of field than long focal length lenses, for example. Rudolf Kingslake waded into that one.

Some of the articles are remarkably deep for what seems to have been aimed at keen photographers rather than a technical readership. Alternative processes are quite well covered, as is colour printing.

Best,
Helen

 

[bob01721]

"... Thanks for taking my reply with grace and good humor. We could use more of that..."

Same to you! My reply was "in kind."

Now... what say we team up and go pounce on some newbies! (Wink. Wink.)

 

[MattCarey]

Somewhere in our family's photos are two portraits signed by J. Edgar himself...I'll have to hunt those down.

Matt

 

[pentaxuser]

Is this a way of getting the exposure just right to eliminate pinko radicals?

Regards,

David

The 1930s were a great period for pinko radicals. They could be bolder then. Remember there was no Polonium 210 in those days.

pentaxuser

 

[bdial]

I generally don't use a gray card outdoors -- I use either in-camera meters (35mm) or a spotmeter (LF). Indoors, with portraits and still life, I use the card as you described.

In a sense, we all use gray cards 100% of the time when using any exposure meter, since they are calibrated to render what they are metering as a mid tone gray. This is why meters are "fooled" by large light or dark regions in a scene. It's also why you can point any photo meter a gray card and get an accurate result. (for rendering a gray piece of cardboard that is )

 

[Helen B]

The 1930s were a great period for pinko radicals. They could be bolder then. Remember there was no Polonium 210 in those days.

pentaxuser

Right. You had to wait until 1950...

(first mentioned in US Camera in August 1950)

 

[DBP]

Some of the articles are remarkably deep for what seems to have been aimed at keen photographers rather than a technical readership. Alternative processes are quite well covered, as is colour printing.

I find the photo magazines I have from the 40s and 50s to be generally more informative than most of what is published today. Those were the days before much of the editorial content became devoted to reviews of new products.

 

[BrianShaw]

The 'Neutrowe Gray Exposure Aid'. It is 14% grey. The article describes, in quite a lot of detail, how they arrived at 14%. It also explains something of the Weston system.

14% grey... probably has something to do with compensation for Weston's K-factor

By the way... if your dentist has 60 year old magazines, what is the equipment like -- are the drills still foot-powered????

 

[Gay Larson]

Did you sneak the magazine's out of the Dentist's office?? I'm often tempted since I usually get half way through an article. Nothing that interesting though. I did not know that J Edgar Hoover was interested in photography.

 

[Richard Kelham]

Right. You had to wait until 1950...

(first mentioned in US Camera in August 1950)

Polonium – at least the natural 208 isotope – was first isolated by the Curies in 1898, though as you say the 210 isotope was created during WW2. I remember having an anti-static brush containing Po back in the 1970s and even then there were regulations for the safe disposal of the item (though no way of enforcing them).

The good news is that Po 120 has a half-life of 'only' 138 days...

 

[jstraw]

The good news is that Po 120 has a half-life of 'only' 138 days...

Yes, if you're the one selling me a new insert for my brush every 138 days! How the heck does a retailer manage inventory on a product only slightly more stable than a quart of milk?

 

[Papa Tango]

Helen, until you clarified your "story" I had some concern over how old your dentist might be...

A couple questions come out of this. At 14%, was this something that correlated to the Weston Scale that was dominant at the time? Was the 14% card an alternative to the 18% (meaning did both exist at the same time)? And, last but not least, did the article (or the historians here) have any opinion on how dominant the use of this "standard" might have been?

 

[Will S]

Yes, if you're the one selling me a new insert for my brush every 138 days! How the heck does a retailer manage inventory on a product only slightly more stable than a quart of milk?

That's only the half-life. If you really only need, say, 40% of the original polonium to get a stream of helium sufficient to remove dust then you are looking at a year of usage. If 5% works then much longer.

Milk, however, especially in its unpasteurized, non-refrigerated form lasts only a few days or maybe weeks and does not "decay" in a consistent and repeatable manner, in case you were thinking of using it as a clock



Best,

Will

 

[Alex Bishop-Thorpe]

I got three bundles of Australian Photographer and Camera magazine today for $5, from around 1970 up until early 1980's from what I've seen so far. Covering everything from how to make your own Cibachromes and lith printing. One was even announcing Polaroid 600's introduction, and anticipating Ilford's XP1. They are a lot more informative than anything I've read in a modern photography magazine, sadly.

EDIT: the first one I picked up had a review for the Canon AE-1P, the first film camera I ever used.

 

[Papa Tango]

We had a thread a while back about the apparent lack of interest in academic detail and rigor that passes for "educational experience" these days. Magazines such as these help to illustrate the gap in understanding and expectation for the delivery of technical information that has occurred in the past 40 years.

Electronic magazines were not just reviews of the latest and greatest gimmick, but also projects the reader could build or how to modify/repair things. Mechanical/science magazines were filled with projects and material lists to accomplish them. As noted, photo magazines held a strong component for the experimenter and to educate on the underlying mechanisms of photography.

Sadly, we have traded most of that for predigested platitudes and "out of the box" experiences. Hurray for this group, for continuing to carry forth the standard!