What is the LIFA P 100 filter mentioned by Dr. Paul Wolff?

[Wagner Lungov]

Advertisement (gone after registration)

In his book Meine Ehrfarung mit der Leica, Dr. Paul Wolf gives the settings of his camera for all the featured images and includes a column about the filter. Some entries for filter show "LIFA P 100" as the filter used. I have found that LIFA stands for Lichtfilterfabrik, that was a company producing accessories for Leica. But I did not find what kind of filter is this P 100. Does anybody have an idea?

[Michael Geschlecht]

Hello Wagner,

Welcome to the Forum.

I do not know about the specific filter you wrote about here, but:

Some Polarizing Filters are indicated with the letter "P".

And, sometimes, some Polarizing Filters which were meant to be used as a pair might have an exposure factor of "100" when used as a pair. At maximum suppression.

Altho this might NOT be what is described here.

This MIGHT be a direction to begin looking from.

Best Regards,

Michael

[Photar]

According to this webpage, P1 designates a light green filter. Can't find any info about P100 (or P 100).

An ND2 (neutral density) filter has an exposure factor of 100.

Is it not possible to infer the filter type from the photos shown in the book? 

[romanus53]

There is a Lifa Panchrom 100 yellow filter on ebay - perhaps that might fit? https://www.ebay.de/itm/256880932038?_skw=lifa+p1&itmmeta=01K0BTWZJ66PRTH383AH7NDZ5Z&hash=item3bcf4bf4c6:g:2VYAAOSwqDBipF84&itmprp=enc%3AAQAKAAAA4FkggFvd1GGDu0w3yXCmi1e8AdvCsGw%2BXiBL%2B370%2FGZWpvhJ1HoVNhS47bMvFcJfYiLjGajw74tkqi5dc7bIoCenu0jzxgMdViYI%2FGxxGsFR5yArI5TfRXg%2BFkkncDOXhnI8cP3I2SmUbk8tp9nYVDT7MAWBnczguFS9cnUEZLrkiQZWDn9pk%2BB%2BKuhxYmaX9sIitZUr3hXy87tw6tS98ymEifYzP9LJh%2BVBApRH%2BbACekJJ9x65ZzeVy04CXEs7a8HppyEcPP0%2F8L7lFnE1OGTHDwhOIhQkmT6UCl0Zjl5U|tkp%3ABk9SR7T68_qCZg

[Wagner Lungov]

Considering that the mentioned pictures taken by Dr. Paul Wolff date from the first 12 years of Leica and the match of LIFA P 100 as LIFA Panchrom  100. I think that this is the case. I guess that at that time films were not sensitive enough to use polarizers or ND filters. A light yellow filter fits better in that context. Attached a picture he took with that filter. Elmar 5cm, 1/30 s, f/4.5, Ortho film and the LIFA P 100 filter. Certainly the intention was to darken the blues in the sky. Thanks everybody for the inputs. 

Welcome, dear visitor! As registered member you'd see an image here…

Simply register for free here – We are always happy to welcome new members!

[Roland Zwiers]

Wagner,

Lifa indeed stands for the traditional filter factory in Augsburg.

It produced dedicated yellow filters for various black-and-white plates (and films) so as to obtain colour-correct results in black and white.

Now really colour correct results often required a strong yellow filter with a big loss in effective film speed.

Also at high altitudes the regular yellow filter would be too strong.

So for these situations a very light yellow filter would do. Almost like a UV-filter.

In my study of Dr Paul Wolff I see that he often uses this very light yellow filter. It just gives sufficient colour correction without a big loss in effective film speed.

Roland 

[willeica]

Advertisement (gone after registration)

8 hours ago, Photar said:

According to this webpage, P1 designates a light green filter. Can't find any info about P100 (or P 100).

An ND2 (neutral density) filter has an exposure factor of 100.

Is it not possible to infer the filter type from the photos shown in the book? 

 

The page linked by Photar above is very useful. Typically, filters were available in various strengths for different conditions and desired effects, particularly the commonly used yellow filters. Below is table presented by Dennis Laney for Leitz filters. Note the strength varies from v.light through light, medium to dense. Also typically the filters would have different 'filter factors' for exposure purposes. Most people, I would imagine, would have experimented with exposure in the pre - TTL exposure meter days

 

Welcome, dear visitor! As registered member you'd see an image here…

Simply register for free here – We are always happy to welcome new members!

This thread, linked below, dealt with some of the issues. I see that I was debating whether Laney was correct about what was screw in and what was slip on. I have recently acquired a set of screw in and slip on filters in 'croc boxes' for the 50mm Elmar, but I have yet to check them out. It is on my 'to do' list. 

In my post I showed a slip on VERAX filter (which also came in a variety of strengths) which resembled the HOYA square filters many of us used in the 1980s. I could be wrong, but I think that Lifa had a similar system in the early days. 

As for the Lifa P 100, I suspect that this indicates a strength of some kind and that the 'P' in it stands for 'panchromatic'. 

I have been debating with Roland about what evidence there is that Barnack used a yellow filter with his early prototypes. Roland has based his views on the photos he has seen, particularly the skies. The earliest items on Laney's list come from 1925, but that does not mean that something was not made up for doing tests before that. I have asked several people in Wetzlar about this but they had no physical evidence that one was used. 

Yet another 'Leica mystery'. 

William

 

 

[Wagner Lungov]

8 hours ago, Roland Zwiers said:

In my study of Dr Paul Wolff I see that he often uses this very light yellow filter. It just gives sufficient colour correction without a big loss in effective film speed.

Roland 

Yes, I was surprised to see how often he used light yellow filters with an orthochromatic emulsion, which is not or barely sensitive to yellow. That meant for sure some sacrifice in film speed that was already low. Perhaps it was more a matter of counteracting the high sensitivity to blue. In modern films like FP4, the sensitivity to blue is not as pronounced compared to the rest of the spectrum, and it's easy, without any filters, to achieve some density in the blue and in provide relief to the clouds, for example. A picture like the one above, today, maybe wouldn't need any filtering.

[Roland Zwiers]

Wagner,

In 1923-1924 Dr Paul Wolff had to use slow, course-grained and weakly orthochromatic films.
In a later publication he complained about the bad quality of the films that were available to early Leica users.
With the exclamation: 'it was a cross'. 

In my working hypothesis these were the same films that Prof Klute took with him in 1923 for his expedition to Argentina and Chile.
I have his books in my collection and Alan wrote an article about this.
One can see that postcard-sized prints are just presentable, but not as sharp as a contect print from a larger negative.
One can say they just serve the purpose.

From 1925 onwards Dr Paul Wolff used (light) yellow filters in combination with highly orthochromatc films,
probably the Perutz Grünsiegel film (after March 1925) and the Perutz Spezial Fliegerfilm (from November 1926 or so).
These films were highly sensitive to yellow, but even with these films the sensitivity to blue and violet was predominant.
So for colour correct results (in German: tonrichtig) one still needed a yellow correction filter.

Now, because these Perutz films were already very sensitive to yellow, a very light yellow filter would already do most of the work without a big loss in effective film speed.
So when a short shutter speed was important, Dr Paul Wolff would surrender colour-correctness for speed.

In later years one can see that Dr Paul Wolff switched to high speed panchromatic films. 
These would be sensitive to all colours, including red.
But even these films required a (light) yellow filter for colour-correct resulst.

High speed films would have a course grain but a softer gradation.
Dr Paul Wolff needed this softer gradation so as to bridge the extreme contrasts between dark and light that were characteristic of his work. 
By a chance discovery (probably around 1930-1931) he found that overexposure in combination with underdevelopemnt still resulted in a fine grain.

The rest is history.

Roland
 

[willeica]

A group of photos taken by Ernst Leitz with the Ur-Leica in the US in 1914 can be seen here. Is there any visible evidence that he used a yellow filter? 
 

https://timeline.leica-camera.com/en-US/years/1914

William 

[romanus53]

vor 1 Stunde schrieb willeica:

A group of photos taken by Ernst Leitz with the Ur-Leica in the US in 1914 can be seen here. Is there any visible evidence that he used a yellow filter? 
 

https://timeline.leica-camera.com/en-US/years/1914

William 

short answer: no, long answer: depends on; 1914 is pretty early, e.g. I've a (german) book from 1920 about how taking pictures in the mountains or snow/winter-time. The author names two groups of yellow filters, one for enhancing the contrast like we still would do with panchromatic film and the other of compensating or adjusting the flaws of orthochromatic emulsions or the ones not even got that part of the spectrum right balanced.

[willeica]

1 hour ago, romanus53 said:

short answer: no, long answer: depends on; 1914 is pretty early, e.g. I've a (german) book from 1920 about how taking pictures in the mountains or snow/winter-time. The author names two groups of yellow filters, one for enhancing the contrast like we still would do with panchromatic film and the other of compensating or adjusting the flaws of orthochromatic emulsions or the ones not even got that part of the spectrum right balanced.

Thanks. Someone has an approached me about these photos, but the set of images they have (many more than are on the link) are fairly low res, so it is difficult to judge. I might reach out to the Leica Archive about this as the set on the link are more high res, but it is still difficult to make judgments about the use of filters. The Leica Archive may have used different source materials such as originals rather than copies. The skies are fairly 'white' on the official set, though. Another possibility I have heard mentioned is the use of treated film, with various chemicals or dyes being used. And, generally, the use of yellow filters was a well known technique for photographers in that era. 

Another aspect of the images is the identification of the locations visited and I have seen some interesting results for various locations, particularly in New York. Some people I know are working on this. It would be nice if we could know the itinerary of the first overseas trip with a Leitz 'Kleinfilmkamera'. 

William 

[beoon]

I have a Lifa filter catalogue dated 1928 and I could not find a reference to "P 100".

The photograph you refer to in his book is dated 1929- 1931.

Here is the page from the Lifa catalogue for reference

 

Welcome, dear visitor! As registered member you'd see an image here…

Simply register for free here – We are always happy to welcome new members!

[Wagner Lungov]

I've started this thread right after receiving the book "Douze années de la pratique du Leica". That is the French translation of "Meine Errahrungen mit der Leica", which I also have. I started analysing the photos and their camera settings and got intrigued by this LIFA P 100 filter. Yesterday, reading the book from the start, I found on page 17 (it is the same in both editions) an explanation by Dr. Wolff himself: "Modern filter sets of the best manufacture take this fact into account [that emulsions at that time yielded better results with light yellow instead of deep yellow filtering] ; they consist of one or two thin yellow filters (so-called fast filters) - (the photographs in this book designated P.100 were taken with a filter of this type)". So voilà, explained by the author. It corresponds to the conclusions we had here from other sources. Sorry that I posed the question before actually reading the book 😁.

[Roland Zwiers]

Wagner, Alan, Romanus, William,

This subject still deserves further clarification!
It is not only a subject relating to Dr Paul Wolff in 1934.
Oskar Barnack and Ernst Leitz II were already intimately aware of the challenge of how to obtain colour-correct results in black-and-white.
This subject is also covered in my article ‘The colour of black-and-white’, which is situated in 1914. 

Unfortunately, post-war Leica literature does not pay much attention to this subject.
And so there are many misunderstandings.
At the same time, this gives me an opportunity for clarification using Leitz literature from the 1910s.

[Roland Zwiers]

In the 1890s the new optical glass from Schott Jena allowed for the production of ever better lenses for microscopes.
This also applied to the correction of lenses for the various colours of the spectrum.
Lens types became achromatic, pantachromatic, apochromatic and so on.
Of course, the higher the order of correction, the more expensive the lens.
The next slide is from a Leitz publication (Wetzlar and New York) from 1894.

[Roland Zwiers]

Welcome, dear visitor! As registered member you'd see an image here…

Simply register for free here – We are always happy to welcome new members!

[Roland Zwiers]

For our discussion it is important to focus on the intensity curve of the eye.
One can see that the colour yellow (between the lines D and E) is the brightest colour by far.
Unfortunately, the traditional colour-blind plates and films were predominantly sensitive to the colours ultra-violet, violet and blue.
This problem, and how to deal with this, was widely discussed in pre-1918 photo-literature.

Welcome, dear visitor! As registered member you'd see an image here…

Simply register for free here – We are always happy to welcome new members!

[Roland Zwiers]

A prominent author in the 1900s and 1910s was Freiherr von Hübl.
He compared the intensity curve of the eye (Roman I) with the colour-sensitivity of an ordinary colour-blind dry plate (Roman II).
One can see that there is very little overlap.
Ordinary plates were even sensitive for ultra-violet, a colour that our eyes do not record.

Welcome, dear visitor! As registered member you'd see an image here…

Simply register for free here – We are always happy to welcome new members!

[Advertisement]

Hallo,

Look here: Interesting Leica gear

[Roland Zwiers]

The approach of Von Hübl had two complementary parts.
First, he created a whole library of photographic dyes for making the emulsion sensitive to specific colours.
But even with a suitable dye, say Eosin, the colours blue and violet would still be dominant.
So the complementary approach was to design filters that would suppress the dominance of blue without sacrificing the colours that had to be enhanced.
In this way he created a special Eosin-filter to complement an eosin-bathed plate or film.

In his handbook of 1910, he even gave instructions to amateurs how to make these correction filters at home.
But amateurs could also buy these filters from what would become the Lifa filter factory in Augsburg.
Which brings us back to the light yellow P100 Lifa filter that was used by Dr Paul Wolff in 1934!