Sunny 16 a little bit of history.

[David Hughes]

I've a pile of old photography magazines going right back to the time of the Great War and found this in one of them.

" ...at maximum sunlight, ie June midday with full sun, the correct exposure in seconds at f/8 is the reciprocal of the H&D speed number."

For the record, H&D published their results and so on about film speeds and sensitivity in 1890 and the writer was relying on a 1920 RPS reprint of their papers to point this rule of thumb out. As we do today, it was attacked in the politest terms but I see it as of great interest. I gather people still used H&D up to the 60's but that's based on the leaflets with some old 1950's and 60's exposure meters.

Regards, David

 

[Roger Hicks]

I've a pile of old photography magazines going right back to the time of the Great War and found this in one of them.

" ...at maximum sunlight, ie June midday with full sun, the correct exposure in seconds at f/8 is the reciprocal of the H&D speed number."

For the record, H&D published their results and so on about film speeds and sensitivity in 1890 and the writer was relying on a 1920 RPS reprint of their papers to point this rule of thumb out. As we do today, it was attacked in the politest terms but I see it as of great interest. I gather people still used H&D up to the 60's but that's based on the leaflets with some old 1950's and 60's exposure meters.

Regards, David

Dear David,

Fascinating, and thank you very much, but although some may have used meters scaled in H&D as late as the 60s (though not many by that time) you can't do a direct conversion from H&D to ASA (because the speed point and gamma are different) so they must have done a rough approximation from a table and then fine-tuned it.

Cheers,

R.

 

[David Hughes]

Hi,

Yes, I suspect they had an old meter and were reluctant to buy new-fangled ones just because the speeds had all changed, again. Looking at 30's magazines you get the impression that things were an amazing muddle but they were beginning to sort things out. F'instance you'd find tables several pages long listing films and how to rate them by what meter you were using and so on. Kodak even advertised a free booklet to do just that...

The letters to the editor and questions were very similar to today's forums; reflex vs Rf etc, cheap vs. dear, etc.

EDIT (about 2 or 3 hours later); I wondered about a comparison with the sunny 16 rule and started looking for proof. The magazines give Dufaycolor film an H&D rating of 400 so a 400th at f/8...

Then I looked at this little leaflet from a box of Dufaycolor - the printer's code suggests 1937 and there's no mention of speed.

And the little table suggests a 5th of a second at f/16 and so ASA/ISO 5 for its speed. Amazing isn't the word...

Regards, David


PS And apologies for the photo's grabbed under pressure using my phone.

 

[webOSUser]

David,

An interesting bit of history. Thanks for sharing.

The inclusion of second chart of adjustments due to month and time of day is interesting. I suspect that it is based on experience in the UK.

Steve W

 

[Dralowid]

Am I right in thinking that H&D was adopted at some point as the Russian system...GOST?

 

[Sumarongi]

Am I right in thinking that H&D was adopted at some point as the Russian system...GOST?

The H&D system was officially[6] accepted as a standard in the former Soviet Union from 1928 until September 1951, when it was superseded by GOST 2817-50.

https://en.wikipedia.org/wiki/GOST_(film_speed)#Hurter_&_Driffield