A photo history Question: b&w slides

[jim kerr]

Was there B&W slides back in the 30's,40's,and maybe the 50's. I'm

not refering to just using a special reversing kit but a direct

positive film...Jim

[al_kaplan1]

There were certaily B&W "film strips" used by schools in special film strip projectors. The images were Olympus Pen sized half frame, essentially movie film frame size. I imagine that they were printed the same way as movies were, from a negative onto positive print film.

[stephen hazelton]

They had kerosene-powered magic lantern projectors way back when. Once again, probably done by contact printing a negative onto another negative. I'm not familiar with the details, but assume there were no direct-to-positive development methods. I don't remember reading of any in the older books I have.

[patrick_gainer]

Reversal processing has been known for a long time. I'm sure B&W home movies were processed that way. Slides and movies for mass distribution were shot as negatives and printed on film.

 

Reversal processing requires a film with low base density and high contrast capability. Any film can be processed to direct positive, but the results are not always rewarding.

[kelly_flanigan1]

Direct positive film in 35mm and 16mm was used in movie work; but probably 16mm was alot more popular for school football scouting films; TV news reels; engineering high speed cameras (fastax); and simple filmstrip for schools.<BR><BR>Regular 35mm still films such as old Panatomic-X was reversable; usually shot at about double or more the asa setting. IE; 64 to 80 for old asa 32 Panatomic-X; in the reversing Kodak kits. Later Tmax 100 was often used. With MACO UP 64c; asa 50 as negative; 64 as slide film. AI /AIM in LosAngeles may well still process regular B&W films as slides.

[barry_wilkinson1]

Hello Jim,

 

I'm not sure when Agfa started producing Dia-Direct B&W slide film. Originally it was 32asa, but changed to 12asa in the late 80's.

 

Might be worth investigating?

 

Barry

[titrisol]

I think the answer is yes

 

I have a lot of stereo-glass plates taken by my grandfather in the 10s-40s and those are positives. My father remembered that his dad developed them like that straight... so they should have been diapositives

[winfried_buechsenschuetz1]

I have a german book on ameteur photography ('Taschenbuch der Photographie' by Dr. Vogel - it has been revised and reprinted a thousand times between 1910 and the 1920's and obviously was quite popular) from the time of WWI. It mentions special plates (and processing methods) for b/w slides (on plates) and has a chapter concerning 'projecting' which is possible with slides only, of course. But this was no direct positive method, still a negative was used as source and then copied to glass plates again.

 

Light sources were gas flames and also electric light (both electric bulbs and arc light, it also mentions an obsolete method of generating light by electric current with the so-called Nernst bulbs).

 

It seems that b/w slides have been made long ago, not so very far from the roots of photography.

[winfried_buechsenschuetz1]

AFAIK there is no such thing as a direct positive film - neither in b/w nor in color. I.e., there is no film which will give positive pictures after a conventional processing procedure with one step of developing.

 

The light-sensitive stuff in b/w films are silver-halogenide which are developped to metallic silver by all development agents I know. Metallic silver is opaque, so the areas exposed to bright light will be dark on the processed film. Whether you use a 'slide b/w film' like Agfa Scala or whether you use standard film with a reversal process: there will always a step of second exposure (or chemical activating of the non-exposed silver halogenides) plus a second step of processing.

 

It is similar with color reversal film. They are basically color neg films processed (and exposed) twice (if they processed once only you will get something similar to a color neg, also called 'cross processing'). The main reason why color slide film was introduced prior to color neg (print) film is that it was very difficult (and costly) to make color prints at that time.

[titrisol]

Going further... if we process a c41 film into e6 chemistry do we get a positive with a strong orange bse?

[fabio b]

i'm sure a pow of last year (2004) was taken on a direct positive bw film - someting of a museum view. i can't remember exactky, but some comments was on the film.

[Bill C]

>> AFAIK there is no such thing as a direct positive film - neither in b/w nor in color. I.e., there is no film which will give positive pictures after a conventional processing procedure with one step of developing. <<

 

Winfried, I'm glad you had the decency to say "AFAIK". Such products have certainly existed. I personally played with such a litho material quite a few years back; it was extremely slow as I recall, and simply developing in Kodak's A+B litho developer gave a reversal image. That is, if you were to contact print a film negative, you would end up with another negative.

 

At any rate, these materials are called "prefogged direct positive" or the like. With the right name, I'm pretty sure an internet search will turn up some information. The mechanism seems to be much related to solarization, about which William Jolly's interesting web site has much information: http://www.cchem.berkeley.edu/~wljeme/SOUTLINE.html

 

Because of certain characteristics, I kind of doubt any of the other "direct reversal" materials discussed in this thread had the reversal actually built into the film. Possibly the materials referred to by Pablo Coronel, but the evidence does not seem very firm; "My father remembered that his dad developed them like that straight...".

 

At any rate, I just wanted to confirm that such commercial materials have existed. Also, according to Jolly's information, the solarization effects were known of prior to 1900 or so. So it seems possible that such automatic reversals (not due to the wet processing) MIGHT HAVE been done in the time frame Jim Kerr has asked about. My best guess, however, is that develop-bleach-fog-redevelop processes would have been much more likely for commercial work.

[winfried_buechsenschuetz1]

Of course I don't know all existing films and all that have existed. I have found information about a technical film made by Kodak which gives a positive image when processed with a standard method. There has also been a b/w slide film by Agfa (DD12 or similar) but it had to be processed in an Agfa lab. There has also been the Polapan film, a 'direct' b/w film which used a special process performed in a little machine you had to buy. The film was ready for projection in a few minutes.

 

You are probably correct that some of the direct b/w slide films were based on the principle of solarization, but I can't really imagine how the process of solarization can be controlled when taking shots of real scenes.

[rowland_mowrey]

FYI, Eastman Kodak produced several B&W and Color direct reversal products based on direct reversal emulsions.

 

They did not give the traditional negative image when developed with a conventional emulsion, but rather gave a direct positive image. The common use for color was in a product called Directachrome used in photo booths espeically in Europe in the 70s and 80s.

 

In addition, Kodaks PR10 instant print material used these direct reversal emulsions as did the Ektaflex R PCT paper, both of which have been discontinued.

 

These were very specialized emulsions which internalized the exposure and fogged where not exposed, thus giving a black where no exposure took place and a white where there was exposure (or color as the case may be).

 

Ron Mowrey

[Bill C]

Thanks for the info, Ron. I had wondered if these materials could have enough speed for pictorial use; knowing they were used in photo booths answers that question.

[rowland_mowrey]

Bill;

 

The highest speed I know of was ISO 3000. (Surprised?) Heheheh. Who knows what lurks within the shadows of EK research.

 

Ron Mowrey

[kelly_flanigan1]

In the 1950's; our free 620 and 120 box cameras were often dropped; and got light leaks. This fogged the film; and sometimes made a direct reversal appear in the deep shadow areas. One image I took as a kid has the neighbor kids in a treehouse; it appears as a postive on the verichrome; and the better exposed areas appear as a negative. when printed; the well exposed areas are a postive; and the under exposed treehouse is an negative.

[j.w.]

Several summers ago (2002-ish), on a weekend car trip around my state, I shot 3 rolls of Tri-X super 8 film, in a canovision super-8 camera. Of course, super-8 film available today no longer comes with the magnetic coating for sound on film, so it was silent (aside from the background, staccato sound of the projector gate).

 

Not sure if the Tri-X emulsion in Super-8 is any different than whats available for larger formats; my gut feel tells me that its pretty much the same, considering the economics of manufacturing. Its obviously the processing that's different, but I'm not sure if they're re-flashing the film after the first developer and bleach with light, or using a chemical fogging agent.

 

It might be interesting to find out, for those who desire to home process super-8 footage. With the cost of processing, it works out to $10 per minute. But if one could reversal process at home, the cost of super-8 goes down to around $5 per minute, which, considering the resolution of fresh film properly projected, looks really great. Talk about the "silver screen", I never experienced that until I projected these 3 rolls. Wow!