GoofyNewfie Loc: Kansas City

Anti-hailation backing kept light from going through the film, reflecting off of the pressure plate and bouncing back to the film from the back. I guess that makes me an "old foggy"

pipesgt Loc: Central Florida

An anti-halation backing is a layer found in most photographic films. It is usually a coating on the back of the film base, but sometimes it is incorporated between the light-sensitive emulsion and the base. The light that passes through the emulsion is absorbed by the anti-halation layer. This prevents any light from being reflected back through the emulsion from the rear surface of the base, or from anything behind the film, and causing a halo-like effect around bright points or edges in the image. The anti-halation layer is rendered transparent or washed out (as in K-14 films) during processing of the film.

The lack of an anti-halation layer in Kodak's High Speed Infrared film (HIE) is the cause of the ethereal "glowing" effect often associated with infrared photography[1], rather than an artifact of IR itself.
http://en.wikipedia.org/wiki/Anti-halation_backing

rayford2 Loc: New Bethlehem, PA

Now that you mention it, I'm guessing contact printing was one of the main reasons for some of the larger format cameras. No enlarger needed.
I bought a 116 Ansco film camera for that reason. It took postcard size pictures and with the right paper you could mail them. The pictures wouldn't win any awards for resolution but they got the point across.

Sunrisepano Loc: West Sub of Chicago

I just caught part of a news story this morning about a camera that is on tour. It is a view camera that is so large it is on the trailer of a truck and takes a 6 foot negative. But, a contact print wasn't good enough. They ENLARGED it to 2 1/2 stories. What is that!? 25 feet?!

A number of years ago, a fellow working part time at the studio I was at went on to Columbia College in Chicago to study photography. He was featured on the inside back cover of the Chicago Tribune Sunday Magazine for using a 20" x 24" Polaroid camera.

One more aside, Fuji is making the "Polaroid" wait-to-develop-and-pull-apart film. I heard a rumor last year that they might bring back the SX-70 film. Haven't seen anything else on that.

bdavis

Anti halation backing is a layer on the film to prevent light from "bouncing" back either from the film layers or even the film housing. Infrared film I grew up using didn't have it so you had to load in low light...otherwise light could "bounce/reflect" it's way across the thickness of the film and past the fuzzy barrier at the entrance of the film cannister. Without the anti-halation backing, infrared film was very thin (in actual thickness...not referring to film density). It would curl up like crazy after drying and was tought to get into the negative sleeves.

I still purchase B+W infrared for my high school students to shoot but it's Ilford, not the old Kodak, and the film base is thick (normal) and doesn't curl. It also doesn't produce the glowing edges around green leaves in bright sunlight like the old infrared. I have assumed that is because they do add the anti-halation backing though I don't know that for a fact. I do know that my students prefer to shoot color digital and then create the look of B+W infrared using Photoshop. I think if I could get them B+W infrared film without the A-H backing that gave such crazy effects they'd dig it. I was using it up into the early 90's but have only found the Ilford now.

FYI: When I trained as a forensic photographer we used B+W Infrared film with a true IR filter (89 I think) that only allowed IR light wavelengths through. You had to set up on a tripod and focus without the filter, then attach it and bracket the heck out of the shoot because you could not see through the filter and the meter had no clue. But it allowed us to search for gunshot residue on a navy blue policeman's shirt soaked in dried blood to prove the relative distance of the muzzle (very close). The resulting B+W print made from the best neagative on the roll made the navy blue shirt appear light gray, the blood did not appear, and the gunshot residue was black (very dark grey).

bdavis

PS: When shooting with the IR Filter in bio-medical settingse we also used a very expensive quartz lens without a lot of the coatings ones normally finds on lenses. I've thought of showing the application to my students but the cost of the lens is prohibitive and the filter isn't easy to find. I keep my eye open on the internet though.

Photo6 Loc: McHenry, IL

An additional reason for the anti-halation layer was that on the backside of the rolls were a series of arrows then numbers which were visible on box cameras through a red sliding window cover. This allowed the advance to the next frame for older box cameras which did not have fixed advance mechanisms. Many of those cameras are now still found in antique stoes. The photographer watched the arrows advance until the next frame number came into the small window. Some cameras had square format, others larger. In all, there were four or five size formats allowed on the film each in seperate rows on different positions on the back of the respective cameras. It was a simple method to allow the flexibility of the same film for newer developments in camera and lense technology and formats of the day. All of this became needless with the advance of professional 2 1/4 format technology which left Kodak in the dust due pioneered by German and Japanese companies. Kodak, however, continued to produce high quality 2 1/4 and larger format cameras for the war effort during WWII.

rayford2 Loc: New Bethlehem, PA

The family and I had several of these cameras with the red window. Dad used to get frustrated loading these things during hurry-up shots. Especially cranking that round knob a dozen times until he passed all the advertising, arrows, fingers and dots to get to #1.
Even worse was winding past a number, of which there was no turning back.

One Jughead Loc: Greene County, OH

Plus X and Tri X were also some of the films of that time.

ronz Loc: Florida

The ASA is 125 but I have pushed it to 1200 easily and it could probably go higher.....

rayford2 Loc: New Bethlehem, PA

Kodak used to market Super-XX (not Tri-X) in the early '50's. I used a roll of it in a Brownie camera thinking this was a super film....Yecch. This film wasn't intended for fixed-lens fixed-shutter cameras (and developed by a drug store contractor).
It was my first lesson on film ASA (now ISO).

WAL

Ortho Chromatic film was often used for male portraits. Because it would darken men’s lips. And create a ruddy masculine look. It is still available in sheet I assume it is not made by Kodak.

My father developed film in the kitchen sink and contact printed it. I still have the Kodak frame he used. I found playing with the paper rolls a special pleasure. I am sure it instilled a life long interest in photography. If my father could see a 13x19 inch print coming out of my Epson printer he would think the devil was involved. Hew as limited to about a 2”x5” from his folding camera

r.reeder Loc: Mesa, Arizona

You can get the orthochromatic effect by using a blue filter, like a Tiffen #47, really dark blue. Reds turn out dark, Blues turn out light. Tree leaves get really dark. Pictures from WWI were mostly orthochromatic.

ianhargraves1066 Loc: NEW SMYRNA BEACH, Florida

Just saw your post re: Vericrome Pan. Absolutly correct 125 ASA when developed in D76 a little slower say 100 ASA in Microdol. Most Verichrome film was howver used mainly by the general public and processed in commercial labs. Again most of the cameras in those days had very limited exposure controls and the film was designed to be exposure tolerant.

The anti-halation layer was a slightly greeny tinge to it but was only to prevent light scatter in the film base, not as a anti reflection stopper off the back pressure plate. The inside surface of roll film had a black coating on it to render the film lightproof when rolled up. On 35mm film cameras the pressure plate was black anyway and did not cause refelections. Many of the newer photographers are and were unaware that the "emulsion in which the silver was suspended was a glorified mixture of egg white. I still use 120 rollfilm even now and still get a thrill every time I process a film and remove the fixed and washed film from the spiral and hang it up to dry. However 120 roll film is almost $10 a roll and at just 12 exposures its getting expensive. Commercial labs charge $10 each to process the film as well. Digital here I come.

Ian

Ian

rayford2 Loc: New Bethlehem, PA

Thank you for your reply, Ian.