Silverbased

Okay, you sun-belters out there quit snickering right now. Here in Michigan, it’s definitely still winter. (March 27th dumped yet another mini-blizzard on us.)

After many months of low temperatures, the earth our city water pipes pass through gets rather chilly. The other day, I measured the water from my cold tap at below 43°F (6°C). Ouch! This presents a problem when you want to mix photo chemicals; or when you need to rinse developed film and prints.

Whoah, bummer.

Water of such low temperature is not effective at removing the fixer that remains in a gelatin emulsion. And years later, that fixer residue might cause brown stains on the image. Also, the shock of going from developer temperature (68°F) to something so cold could make a tender negative emulsion shrink and crinkle.

A negative is irreplaceable. So I generally exceed most manufacturers’ wash recommendations—erring on the side of caution and going for 15 or 20 minutes. And Lo, how I have often fiddled with balky hot and cold water taps, trying to get the rinse temperature to stay at a constant 70°F or so during that whole time.

There are really several irritations with this method:

• Dissolved gas bubbles from the hot water always cling to the film surface. Does this interfere with washing efficiency? I don’t know, but I worry it might.
• No matter how much I fiddle, the water temperature always drifts from the temperature I set by tweaking the tap handles (yes, I know thermostatic taps exist, but one at the kitchen sink where I develop film seems like overkill).
• I often walk away to do something else while the film is washing—then forget I’ve left the taps running until an hour later, wasting water.
• In fact, I only have a vague sense of how much water the running-taps method uses; and little confidence that my washing is consistent from film to film.

What are we trying to do here?

Now, my hunch is that any liquid fixer clinging to the surface of the film is rinsed away within a few seconds. The purpose of film washing is to get the fixer molecules that have diffused into the gelatin to migrate outwards again.

For this purpose you shouldn’t need to blast the film with extreme water velocities. You only need enough water flow to give a good diffusion gradient, from the fixer embedded in the emulsion to the fresh water outside it. (I suspect that the time the film remains submerged in the rinse water is more important than the water velocity.)

So this month I had a brainwave for a new low-velocity method for rinsing film, one that solves several of my earlier problems.

The New Way

First, fill a 5 gallon bucket with 70°F/21°C water, and allow it to stand until all the dissolved gas bubbles float to the surface. Obviously you need to use a well-scrubbed bucket, without any residues from its prior uses. I might set my stopbath and fixer bottles into this water for a half an hour before starting to develop, to equalize them to the proper processing temperature.

Take a length of tubing 4 feet long (120cm), and with an inside diameter of about 3/16″ (5mm). Attach this to the lip of the bucket in whatever convenient way will suspend one end at the bottom. Here I’ve used a binder clip:

Five-gallon bucket, tubing, & binder clip

Place your film tank in a sink where the rinse water can overflow from its top; support the bucket at a height where its bottom is at least 8 inches above the top of the tank.

When you are ready to begin rinsing, suck on the free end of the tubing until water begins siphoning out of the bucket—keep the tubing’s end below the water level.

Fill the tank once with water, then dump it all out. Then stick the tubing into the center spindle of your film reel; and once you’ve confirmed that water is overflowing from the top of the tank… walk away!

Siphon washing at work

After about 20 minutes the bucket will empty. A soft gurgle will announce the end of your film rinse. An unexpected bonus is that otherwise, this method is totally silent—unlike the distracting whistle of keeping taps running.

The water flow will be highest at the beginning, then slow down as the water level drops—which is appropriate for rinsing away fixer. There’s no clinging bubbles; and no surprise temperature lurches if someone in the house flushes a toilet. And you always know exactly how much rinse water you used.

If you’re feeling especially thorough, you may wish to check how the rinse is going at the halfway point. Dump out all the water and invert the reel, just to insure totally uniform washing.

This inspiration for this new method only came to me after, oh, 40 years of developing my own film—struggling with the minor irritations of the running-taps method. Oh well. That’s another thing I love about photography: You never run out of new things to learn.

[In case you've never developed your own B&W negatives, it's easy—see this earlier article to get started.]

A while back our local Crappy Camera Club had its monthly meeting. These often turn into freewheeling swap meets—cleaning out our closets of whatever arcane retro photographica we think someone else might use.

Thus I returned home with various oddities, including a 1918 Ansco folding camera; and also C.E.K. Mees’ 1942 text, The Theory of the Photographic Process. The Ansco even contained an old roll of 120 film, with most of the frames already exposed.

HC-110, Dr. Mees, and my mystery roll

Found, exposed film always makes me tingle with anticipation. I fantasize I might be the first person to reveal some achingly beautiful lost image or poignant historical document. But you only get one try at developing it correctly; and when you have no information about the film’s age or history, there’s some nail-biting uncertainty hoping you won’t totally screw it up.

With old films, the main concerns are loss of speed and contrast, and high levels of background fog. So generally you want to push the development a little longer than the original specs, using a developer that won’t make the fogging any worse than it already is.

I am a fan of Kodak’s syrupy developer concentrate, HC-110. And while I’ve never run any comparisons myself, it has the reputation for low fogging even with push processing (as noted at this page of excellent background about HC-110). So that seemed the right developer to try.

The mystery roll was Kodak Verichrome Pan. I knew it was much younger than the camera, since the Pan version of Verichrome had only been introduced in 1956. The stickum band on the tail of the backing paper had a note about “new developing times”—these matched the ones given in my 1965 Kodak Master Darkroom Dataguide.

So roughly speaking, this film was manufactured about 50 years ago. I guesstimated that I ought to give about 30% more development time than Kodak’s original recommendations—about equivalent to a one-stop push.

Doctor Mees Gives a Clue

C.E.K. Mees was once the legendary head of Kodak’s research division. His massive tome includes 1100 pages of formulas, tables, and diagrams about the chemistry of the photographic process. My own knowledge of chemistry is rather shaky, so I am not ashamed to admit that almost all of it went completely over my head. And for all I know, some of the book’s validity may have been overturned by later work.

But I discovered one intriguing table on pg. 455. This listed the ratio of image density to fog density, for various developing agents used at different temperatures. What leapt off the page was that for certain developers, the image-to-fog ratio was twice as good at 15° C as at 25° C.

Eureka! Another way to reduce fogging is simply to develop at a cooler temperature. Of course the developing time must be extended to compensate. I didn’t want to go too cold (I had not pre-chilled my stop and fix to match), so I mixed HC-110 dilution B at 64°F/18°C, then used a development time of 8 minutes.

The results looked quite good, with a nice density range and surprisingly little fog. Not bad for such ancient film!

Fifty-year-old film developed in cold HC-110

And the images? Well, unfortunately I found that at some point in the intervening decades, the back had gotten opened, flashing several frames. The three which survived showed woods and a riverbank in the snow—a landscape which certainly could be Michigan.

But maddeningly, there were no people, no cars, and only one house (of indeterminate age) seen through woods. Only a few ghostly boot-prints in the snow appeared, to whet my curiosity about the long-lost photographer.

The “one way” image above was the only one which offered any clues…. So if anyone thinks this looks familiar, I’d be grateful to hear about it.

I Heart Verichrome Pan

I have a long history with Verichrome Pan: It’s the film I used for my first photograph ever. I’m hardly alone in this, since for decades it was America’s premier snapshot film. I find its soft tonality quite nice, and wish it were still around today.

Verichrome Pan is best known for its extended exposure latitude, which saved the day with non-adjustable box cameras used in varying lighting conditions.

But it was also a film intended for the occasional snapshooter, who might throw the camera in a drawer for six months between holiday photo-ops. So the emulsion also had a long shelf life, and good stability of the latent image.

Thus, when you turn up some ancient mystery roll, if the emulsion is Verichrome Pan your chances of recovering usable images are much improved.

Who Put the Chrome in Verichrome?

A final note on Verichrome Pan: The name often confuses photographers today, accustomed to the convention that a “chrome” film (like Fujichrome or Ektachrome) is a color slide film. Verichrome has always been a traditional silverbased black & white emulsion—so why the name?

The history here is that 1956’s Verichrome Pan was a revision of a 1931 B&W film simply called Verichrome. In 1931, no one would have presumed this was a color film—because they didn’t exist. The Autochrome process only worked with glass plates; and Kodak’s own Kodachrome film would not reach the market until 1935.

The name Verichrome was chosen to suggest “truthful rendition of color” into black and white tones. But even this is a bit puzzling from our perspective today: The original Verichrome had no sensitivity to red light at all!

Ortho vs. Pan

The native spectral response of a silver-halide emulsion is to blue light only. However by adding sensitizing dyes, Kodak was able to give 1931 Verichrome a fairly balanced response across blue, green and yellow colors of light—while still allowing it to be handled under a red safelight. Emulsions of this kind earned the name “orthochromatic,” for a color response more correct than the earliest blue-sensitive kind.

Despite the occasional oddity of red objects appearing as black in photos, Verichrome continued as an ortho emulsion up until 1956; at that point Kodak replaced it with Verichrome Pan. And, you guessed it, this was “panchromatic”—sensitive to all colors of light.

It might have made some sense to replace the Verichrome trademark at that point—but the name’s brand recognition was far too deeply entrenched with consumers for Kodak to tamper with it.

However besides the name, the decades of ortho Verichrome left another lasting heritage: The millions of snapshot cameras whose frame counters are a little peepsight window, covered in red cellophane.