I found some sources that claim that using polarized light in the enlarger gives deeper blacks and crisper clearer images
I have a source that claims the earth is flat.
Really. http://www.theflatearthsociety.org/wiki/index.php?title=Frequently_Asked_Questions I keep hoping it's a joke.
It's an exercise in logical argumentation, actually.
More intriguing than that Flat Earth theory is that Hollow Earth theory, stating that we actually live in a world at the inner side of a sphere, not on the outer side.
It makes perfect sense if your skull is likewise hollow.
So what is your hypothesis of what a theory means?
Now that we're totally of topic, I can say that I've actually photographed the memorial statue of the man who came up some of the "hollow earth theory." it's located in Hamilton, Ohio. Dead Link Removed
I found some sources that claim that using polarized light in the enlarger gives deeper blacks and crisper clearer images
Several years have passed without new contributions to this thread, and I can tell you that the use of polarized light combined with a polarizing filter for black and white enlargements was a common practice in the commercial laboratories that Agfa-Gevaert had in Buenos Aires. Fixed gradation papers were used (not variable contrast) and the contrast of very contrasted negatives was diminished by attenuating them a little with the polarizing filter. This is because the denser parts of the negative maintain the colloidal properties of the photographic emulsion and slightly depolarize the light that passes through them, while the lighter parts do not. By slightly blocking the passage of polarized light with the filter, differential control is gained over the light passing through the shadows and highlights.
Basic physics tells us that polarized light can become de-polarized when scattered by the emulsion, but not necessarily the other way around.
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The article you posted gives an example of how polarized light can be partially depolarized by scattering, but it says nothing about whether unpolarized light can become partially polarized by scattering. In fact, scattering often does polarize light: this is why reflections off some surfaces are polarized. The amount of polarization depends on the dielectric properties of the scattering medium. For example, https://sciencedemonstrations.fas.harvard.edu/presentations/polarization-scattering
I don't know, of course, whether scattering in the film emulsion was the real effect that the OP's master printer was trying to control with the polarizer. Printing (especially, I imagine, printing at very large sizes) is a craft that has a lot of empirically derived practices that should be physically justifiable after the fact, but aren't easy to deduce from theory in the absence of practice.
When was this? Was this for printing smaller negatives like 35mm, 4x4 cm , 6x6 etc or large format? A lot of this knowledge is gone. Welcome to Photrio!!!
First guess : a tungsten point light source with a polarizing sheet in the filter drawer above the lens stage.
It just seem strange that as little as 10 years ago a talented printer seem by Stephen Frizza had decided to stick with graded paper and this method of a polarising filter. Maybe this was so unique a method that none of us with the exception anakhan knows anything about it? Hence the speculation as to how it achieved whatever it achievedI guess anakhan is referring to the 50's and 60's when agfa manufactured photographic paper as did ferrania in Argentina. As for the type of film, in which this method was used, I don't think it was LF. It was almost non-existent in Buenos Aires.
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