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NormaN
1-Nov-2022, 15:57
Hello all

I recently bought an Eastman Ektar 14 inch.

According to "CAMEROSITY" it is from 1940, uncoated. Normally the two letters are followed by a three digit number. Some models before about 1945 have the letter "K" appended. After that they are "Lumenized" (Weston uses a 1946 model in the attached film).

https://www.youtube.com/watch?v=g4aE2f07ON4

Does anyone know what the letter "K" means? Is this an indication of the soft coating on the inner surfaces?

I read somewhere that magnesium fluoride was used. Or is it "K "alzium fluoride?

In addition to the photo of the lens and the film, I have attached the second page from a brochure from 1938 where the "Eastman Anastigmat Ektar f.6.3" is advertised.

Thank you for your help!

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Greg
1-Nov-2022, 16:32
Something also to be aware of: In 1961 Burke & James had a "Lenskoting Department". "Lenskoting is the modern surface treatment for all glass-air surfaces." per their 1961 catalog. "The service is nominal - service is prompt." I once owned a 14" Ektar that was "Lenskoted" by B&J. The only way that I knew that was because a receipt for their "Lenskoting" service was included with the lens. I did once read that their "Lenskoting" Ektars was very popular back then. Did it make a difference with Ektars? I say questionable.

David Lindquist
1-Nov-2022, 17:56
My Kodak Reference Handbook copyright 1945 indicates that many (but not all) of their Ektar lenses were coated on the internal surfaces. In particular the Ektars for the Ektra camera and the Eastman Ektars were coated internally. Doesn't say what the coating was. It's my understanding that it was too soft to use on external surfaces. From a cursory google search it looks like magnesium fluoride coatings are reasonably hard so I'm guessing it was something else. Hoping someone will come along who knows what it was and also why they didn't go to magnesium fluoride coatings right away.

The Eastman Ektars became the Commercial Ektars; the Commercial Ektars had both internal and external surfaces coated. The film's copyright is 1948 so that could be a Commercial Ektar. My hunch is Eastman Kodak provided Weston with a Commercial Ektar not wanting their Kodachrome subjected to the vicissitudes of Edward's uncoated Turner-Reich Anastigmat.:o

Up into the 1970's there was a place in Pasadena called Pacific Universal Products that did lens coating, they called their process "Acra-Coat" (not sure of the spelling).

David

Mark Sampson
1-Nov-2022, 18:30
This question came upon Photrio a while back. EK changed the "Eastman" name to "Kodak" on those lenses post-WWII, when civilian production resumed. Those lenses were coated, where the "Eastmans" had not been. In addition, EK continued production of "Anastigmat" lenses, similar to the Ektars but uncoated.

There was a great deal of speculation on Photrio... but no one was able to find an answer about the mysterious "K". I suggested that the OP over there contact Todd Gustavson, the technology curator at the George Eastman Museum, which holds Kodak's patent museum (along with a great deal of EK's history). The last time I looked, the OP had not received a reply. Someone else suggested a search in the library at the University of Rochester, which holds other Kodak archives; I don't know if anyone's done that yet.

I worked for Kodak as a technical photographer and lab rat from 1984-2004, and then for ITT until 2010, after EK sold my division to them.. I was based at the Hawk-Eye plant, where those lenses had been made. We used many Ektar lenses on the job; but all the people who had made the Ektars must have been long retired by then.
I even had a 14" Eastman Ektar in its original ebony box as a desk ornament. It may never have been used (or left the building where it was made). That one was EY 000, I recall, but no extra "K". We may never know.

Dan Fromm
2-Nov-2022, 03:49
Alzium? Wozzat?

NormaN
2-Nov-2022, 14:54
Hi all Dnke you for the interesting background stories.

@Greg
You mean that for the early versions someone outside Eastman did the coatings?

@David:
Found a photo of an early model (see attached). There are no prefixed letters here, just the 3 digits and the ominous K appended.

@Mark
Thanks for the hint about Photrio (haven't found it yet).
I would also like to browse the archives or the George Eastman Museum, preferably on site (unfortunately I live far away in Switzerland). Maybe I will make contact by mail....

@Dan:
That was just pure guesswork
magnesium fluoride was used as a coating
Maybe calcium fluoride was also used and hence the K for "Kalzium"
Or K for Kodachrome
Or K for Kodatron / something about flash use

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Greg
2-Nov-2022, 15:43
You mean that for the early versions someone outside Eastman did the coatings?

Burke & James Inc in Chicago, Ill. was a huge photographic equipment store in the 1960s. They advertised that they were the "World's Finest Photographic Equipment (store) for over 64 years" back in 1961. They offered a full range of photographic equipment, custom lens grinding and polishing, Lenskoting, quality control measurements, precision engraving & calibration, modern auto-collimation, and more. They also had a huge lens bank of vintage and new lenses. Burke & James was also a prime and major contractor for the United States Government. As far as I know Eastman Kodak did not use them for coating their lenses. My 14" Ektar is from 1947. After the three digits is the capital letter L with a circle around it. I was told by the original owner of the lens that this indicated that the lens was coated by Eastman Kodak. Sidebar: The original owner also told me that he only used the lens a few times which makes sense since the lens today is in absolutely mint to like new condition.

David Lindquist
3-Nov-2022, 07:42
Hi all Dnke you for the interesting background stories.

@David:
Found a photo of an early model (see attached). There are no prefixed letters here, just the 3 digits and the ominous K appended.

232314

Very interesting example. It's labeled "Eastman Anastigmat" and looks like a precursor to the Eastman Ektar, 14 inch f/6.3 lens. I had not previously known of such a lens but my Eastman Kodak literature for the late 1930's is, well, non-existent. In any case I don't know what the "K" is about.

I think Kodak started using the "CAMEROSITY" code in 1940.

David

David Lindquist
3-Nov-2022, 07:56
Burke & James Inc in Chicago, Ill. was a huge photographic equipment store in the 1960s. They advertised that they were the "World's Finest Photographic Equipment (store) for over 64 years" back in 1961. They offered a full range of photographic equipment, custom lens grinding and polishing, Lenskoting, quality control measurements, precision engraving & calibration, modern auto-collimation, and more. They also had a huge lens bank of vintage and new lenses. Burke & James was also a prime and major contractor for the United States Government. As far as I know Eastman Kodak did not use them for coating their lenses. My 14" Ektar is from 1947. After the three digits is the capital letter L with a circle around it. I was told by the original owner of the lens that this indicated that the lens was coated by Eastman Kodak. Sidebar: The original owner also told me that he only used the lens a few times which makes sense since the lens today is in absolutely mint to like new condition.

The "L" in the circle stands for "Lumenized" which was Kodak's name for applying a hard anti-reflective coating to their lenses. Similarly Wollensak lenses had a "W" in a circle for "Wocote", their name for this process. My thanks to Dugan for correcting my spelling here.

I think Bausch & Lomb used the term "Balcoated" (again not sure of the spelling), don't know if they had a symbol they engraved on the lens mount for this.

Schneider marked their coated lenses with a red triangle and Zeiss, famously, marked theirs with a red "T". Schneider and Zeiss eventually dropped these markings. Zeiss revived the red "T" adding an asterix ("T-star") for their multicoated lenses.

Photographic lenses, at least those of quality, seem to have been universally (or nearly so) hard coated beginning shortly after the end of World War II which makes me think the technology for doing this en masse was developed during the war. I have seen statements that Zeiss was doing this before World War II but not on all their lenses.

David

Dugan
3-Nov-2022, 08:17
Wollensak named the coating " Wocote".

David Lindquist
3-Nov-2022, 08:21
Wollensak named the coating " Wocote".

Thank you for that clarification.

David

Mark Sampson
3-Nov-2022, 12:09
I'll agree that EK did not send lenses to B&J to be coated. However, owners of Kodak Anastigmats and Eastman Ektars may very well have done so. It also seems apparent that Kodak, Zeiss, and who else? were coating lenses during World War II, and when civilian production resumed, coating became standard practice across the industry.

Here's a tangentially relevant story. As I said, I worked at the Hawk-Eye plant, a large complex built at various times between 1890-1944. In an interior courtyard there was an an enormous optics-coating machine, or its remnants. It was open to the elements and looked like an oven. It was long disused, as the optics division had moved to newer facilities many years before. Once, I was assigned to photograph it, since the company was considering removing it. But the newer buildings had been put up around it- there was no way this thing was going out through any door. So it stayed; it's probably still there, as that entire complex stands empty now.

Whir-Click
3-Nov-2022, 13:45
Thanks to court records from Dean A. Lyon suing Bausch and Lomb, Eastman Kodak, and Wollensak Optical for infringement of his lens coating patent, we have an interesting and fairly detailed account of the development of U.S. lens coatings in the late 1930’s and early 1940’s.

The 1956 Rochester Times Union clipping below provides a short overview and you can read the B&L case ruling with many historical tidbits here: https://casetext.com/case/lyon-v-bausch-lomb-optical-co
The patent, applied for in 1942 and issued in 1946, is available here: https://patentimages.storage.googleapis.com/db/58/40/27306ea65a7973/US2398382.pdf

Of note in the ruling, “The military services, and particularly the Navy, were particularly anxious to find a practical way of coating binoculars, periscopes and other ‘light-transmitting’ glass surfaces, which should make the film at once tenacious and viable. . . The trouble had been that all the earlier coatings, though their proper composition was known, could be readily scratched or even rubbed off. “

Once a viable hard coating process was available, it quickly became a specification for defense products, at least among U.S. manufacturers. For example, below is Wollensak’s 1943 drawing for a 6x30 prism binocular optical assembly; you can see the 3/6/1944 note referring to the new coating requirement. In 1946 Wollensak began offering hard coating on their commercial products for an additional charge, and in 1947 coating became standard for Wollensak.

Mark, I enjoyed the anecdote about the coating machine irreversibly shoehorned into a courtyard at Hawk-Eye. At Wollensak a coating facility was added onto the roof of the plant at 850 Hudson Ave. I imagine that every manufacturer had to find or make space in a hurry for this transformative process.

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David Lindquist
4-Nov-2022, 12:24
Thanks to court records from Dean A. Lyon suing Bausch and Lomb, Eastman Kodak, and Wollensak Optical for infringement of his lens coating patent, we have an interesting and fairly detailed account of the development of U.S. lens coatings in the late 1930’s and early 1940’s.

The 1956 Rochester Times Union clipping below provides a short overview and you can read the B&L case ruling with many historical tidbits here: https://casetext.com/case/lyon-v-bausch-lomb-optical-co
The patent, applied for in 1942 and issued in 1946, is available here: https://patentimages.storage.googleapis.com/db/58/40/27306ea65a7973/US2398382.pdf

Of note in the ruling, “The military services, and particularly the Navy, were particularly anxious to find a practical way of coating binoculars, periscopes and other ‘light-transmitting’ glass surfaces, which should make the film at once tenacious and viable. . . The trouble had been that all the earlier coatings, though their proper composition was known, could be readily scratched or even rubbed off. “

Once a viable hard coating process was available, it quickly became a specification for defense products, at least among U.S. manufacturers. For example, below is Wollensak’s 1943 drawing for a 6x30 prism binocular optical assembly; you can see the 3/6/1944 note referring to the new coating requirement. In 1946 Wollensak began offering hard coating on their commercial products for an additional charge, and in 1947 coating became standard for Wollensak.

Mark, I enjoyed the anecdote about the coating machine irreversibly shoehorned into a courtyard at Hawk-Eye. At Wollensak a coating facility was added onto the roof of the plant at 850 Hudson Ave. I imagine that every manufacturer had to find or make space in a hurry for this transformative process.

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Thank you very much for this historically important information!

David

NormaN
7-Nov-2022, 13:27
After some searching I found this text in an other group:

"In 1938, Eastman Kodak Company successfully developed its "HECTA" lens coating process, first used on military objectives during WWII"

Does anybody knows more about this "HECTA" coating Process?

I couldn't find anything more.

Tin Can
7-Nov-2022, 15:27
I have a Chicago B&J catalog, I think 1962

They offered nearly anything photographic and custom

Full portable DR, giant lenses, machines

I spent 2 entire days examining it

NormaN
8-Nov-2022, 05:31
I have a Chicago B&J catalog, I think 1962

They offered nearly anything photographic and custom

Full portable DR, giant lenses, machines

I spent 2 entire days examining it


It was crazy what was on offer back then. Many catalogs can be found online, but it is much nicer to leaf through them....

Daniel Unkefer
8-Nov-2022, 08:55
I was invited by Midwest Photo Exchange (they bought the -entire- B&J inventory) along with Ron Wisner (they flew him in) to prevue hundreds and hundreds of boxes, of the entire thing in their basement. Also they supplied good beer and good pizza, what a hoot it was. I bought an uber rare Kern f6.8 Tessar process lens 300mm. A gem to me. Wisner made a -huge- pile of brass stuff to send home. My friend who is a Linhof collector was also with us. What a goldmine :) :) :)

Bernice Loui
8-Nov-2022, 12:03
B&J Lens Bank.. Still have a few odd barrel lenses from B&J lens bank like a B&J coated f3.5 Heilar in barrel.. Still a copy a vintage Lens Bank catalog.
MPEX was once LF view camera "central" they bought out studios and more then offered the "gear" at remarkable values..

Still have many items used to this day that came from MPEX from that era.. Heh, once purchased over 500 rolls of past date 35mm Fujichrome film, absolute bargain per roll.
Took about two years to burn all that.. still have the mounted slides to this day.

Very different place and era in foto time,
Benrice

Nodda Duma
9-Nov-2022, 14:18
Single-layer coatings in the visible spectrum all use Magnesium Flouride. The low index of refraction of MgF2 is what provides the benefit in reduced reflections at the air-glass interface. Magnesium Flouride itself is relatively hard. “Hard” or “soft” coatings refer to adhesion properties of the coating (and to some extent the porosity of the coating)…that is, how well the material adheres to the substrate. This is a function of the coating process used. The early lower-temperature evaporative/thermal deposition processes were very “soft”. More modern methods - electron beam deposition, ion beam deposition, magnetron sputtering, etc, provide for better adhesion and better coating density and thus would be considered “hard” coatings, more resistant to scratches and wear.

Multi-layer coatings require layer thickness control systems which were not possible until the 1970s… so anything prior to that, regardless of the process name or trademark name applied by the marketing departments, were all very similar process single-layer MgF2 and, knowing the industry, very likely used many of the same coating machines across the different companies.

NormaN
11-Nov-2022, 13:28
Thank you Nodda Duma!

Some of you already know this film. From 18:00 the lens coating is described.... The lumenizing method described as hard C
coating using Magnesium Flouride (as mentioned by Nodda Duma in the previous post).

https://youtu.be/tpziDTklPs0


In the meantime, the lens I purchased (mentioned at the beginning of the thread) has arrived. On the back of the lens, small speckles are partially visible under certain angles of view. They are bluish purple in color. They cannot be cleaned. I asked the seller if these might be spots on a coating. He answered in the affirmative and assured me that it does not affect the image quality (he has used the lens himself). ....
I would like to believe him. Held up to the light, you can see practically nothing except at the very edge something like light traces of cleaning.

What do you think?

So can this be a subsequently coated glass?
Or is it a factory (almost invisible) coating?
Or do the speckles have another origin?

I still need to make myself a lensboard to test the lens....

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