Early 40's Ektar Coated?

[E. von Hoegh]

Henry, did you use the 'CAMEROSITY' code to date these?

[IanG]

The article I have in a BJPA gives a few different British Patents regarding early optical coating. From the dates of the Patents it would appear the research work wasn't far behind Zeiss, The British Scientific Instruments Research Association's Patent was filed in 1939. The government controlled the UK photographic industry during the War and coatings would have been important for military optics.

Ian

[Mark Sawyer]

Since British Kodak lenses are also being discussed, it's a good time to point out that while CAMEROSITY was the code in the U.S., Kodak used CUMBERLAND for lenses made in Great Britain.

[IanG]

Mark, I tried checking my 203mm Ektar and 101m Ektar and there's no number.

Well, if people say that they have coated lenses from EKCo made and coated before 1946 I'd be skeptical but wouldn't tell them that the statements are in error.

I just checked on Brian Wallen's site. It appears that Kodak began coating lenses for civilian use in (not at the start of) 1946. In evidence whereof I m'self have an uncoated 101/4.5 Ektar made in 1946.

Well I have a coated 1939/40 US made Dagor but it was coated after WWII and retro coating of lenses was offered in the US.

Your comments about Brian Wallen's site make sense, my Kodak Reference Handbook (1945) implies that many Kodak lenses were now being coated but only mentions Lumenization of two Projection lenses so it was obviously only just being implemented.

I just checked my 127mm Ektar, I'd missed the small L in a circle thinking it was part of the serial number which starts EO so 1946

Ian

[EdSawyer]

All the aero ektars were coated, and date to 1943 or earlier.

[David Lindquist]

Here's what my Kodak Reference Handbook, copyright 1940 and 1943, says about lenses being coated (or as they alternatively say, "treated"):

The six Ektars made for use with the 35 mm Ektra, focal lengths 50 - 153 mm: "Inner air-glass surfaces are coated to reduce reflections…"

The f/2 45 mm Ektar used on the Bantam Special: "Inner air-glass surfaces are treated to reduce internal reflections."

The description of the 100 mm f/3.5 Ektar used on the Medalist refers to "...coating the inner air-glass surfaces of the lens."

For the f/6.3 Eastman Ektars (forerunners of the Commercial Ektars, four lenses 8 ½ to 14 inch focal lenth), this reference says: "...inner air-glass surfaces are treated by a special process which reduces refections…"

The descriptions in this reference for the 105 mm f/3.7, the 101 mm f/4.5 and the 127 mm f/4.7 make no mention of being "coated" or "treated" And likewise for the f/4.5 Kodak Anastigmats, six lenses, 5 ½ - 12 inch focal lengths and the 8 inch f/7.7 Kodak Anatigmat, no mention is made of being "coated" or "treated".

I recall hearing that during this era of coating by Eastman Kodak that the coatings were so soft they were only applied to the internal surfaces. I'd think that in this case it would be hard to tell if any coating was done by a visual inspection.

I don't think this tells us with absolute certainty that no 127 mm (or 105 mm or 101 mm) Ektars were coated until 1946. After all at the time this reference was published Kodak was coating most of its Ektar line and might have begun to do so with these three remaining lenses before the war ended.
David

[Dan Fromm]

David, I have in hand a 101/4.5 Ektar with a 1946 serial number. E0 3946. It is not coated and its trim ring doesn't have the L in circle Lumenized mark. This establishes with certainty that not all 101/4.5 Ektars made in 1946 were coated.

My little lens doesn't establish with certainty that no 101/4.5 Ektars made before it were coated but given the production process I find it hard to believe that any 101/4.5 Ektars made before mine were in fact coated.

[David Lindquist]

David, I have in hand a 101/4.5 Ektar with a 1946 serial number. E0 3946. It is not coated and its trim ring doesn't have the L in circle Lumenized mark. This establishes with certainty that not all 101/4.5 Ektars made in 1946 were coated.

My little lens doesn't establish with certainty that no 101/4.5 Ektars made before it were coated but given the production process I find it hard to believe that any 101/4.5 Ektars made before mine were in fact coated.

I agree with you; I find it hard to believe Kodak would have coated these lenses for a period between 1943 and 1946, stopped for awhile, and then resumed the practice. Also I don't think they put the "circled L" on the lenses they only put internal coatings on. My reference above doesn't use the term "Lumenized" which appears in a later (circa 1952-1962) version I have of the above. I googled Eastman Ektar hoping to find an image to confirm this but didn't immediately turn anything up.

Googling also turned up this obscure reference which would have saved me some close reading and typing: http://www.largeformatphotography.in...c-experts.html
David

[IanG]

So this "Treatment" is quite different to Lumenization which is coating as we know it. Lumenization as a term was in use in 1945. Dan's 1946 lens is listed as "treated" in the 1945 Reference Handbook.

Ian

[JohnJ]

So this "Treatment" is quite different to Lumenization which is coating as we know it. Lumenization as a term was in use in 1945. Dan's 1946 lens is listed as "treated" in the 1945 Reference Handbook.

Ian

The 1948 Kodak Data Book, Kodak Lenses, uses the term 'Luminized' and describes it over about a page.

My 1946 Projection Ektar 4.5/75 (enlarging lens) is 'Luminized', it has a 'L' in a circle and the coatings are obvious. Clearly the term 'Luminized' was being used form at least 1946.