Large Format Photomicrography part: VIII

At this point I haven’t tried to make a print. So far I’ve only gone as far as developing a couple sheets of film to end up with a 4×5 negative. In order to get a look at a negative it will need to be backlit. In the old days this meant using a light box which was really just a deep picture frame containing a light bulb (usually a tube florescent) and fronted by a piece of heavily frosted or opal glass. Light boxes are still around, old and new, with the advent of LED lighting and translucent white plastic they can be had for just a few dollars. That would be a good option if there was a need, but any tablet or LCD display that can be set up to display a solid white background will work nicely.

4x5 B&W negative of assorted diatoms

4×5 B&W negative of assorted diatoms

The Negative Visually

There it is, those are some diatoms. If one looks at the Triceratium (the big triangular one in the center) it’s obvious that a higher power objective was employed. The center of the particular diatoms test is out of focus but the majority it, by this one can tell that the objective used provides only a relatively narrow depth of view. If this was a micrograph (that is a hand drawn image of a microscopic object) then the artist could easily compensate for the narrow depth of field by making slight adjustments to the fine focus while drafting the drawing. In the modern era the fame may be accomplished with a digital photomicrograph by taking multiple identical photomicrographs in which the optical section has been slightly displaced (again with slight adjustment of the fine focus). The image is then combined digitally taking only the sharply focused portion from each to form the final product.

In looking at the negative, even with the bright backlight, it is noticeably dense. There is comparatively little difference between the lights and darks; there’s little contrast. Ideally there should be a large tonal range and significant dark, nearly opaque, areas between the diatoms. Remember, this is a negative so the bright white background of the positive print would need to have a corresponding dense black background in the negative.

4x5 B&W negative scanned as a if it were a color positive

The Scanned Negative

In order to scan a negative one must have a backlit scanner. This could be as simple taking a flatbed scanner and placing the negative on the bed, emulsion side down, with a light box on top while scanning. Fortunately, I have a backlit scanner so I don’t need to bother with such things. In the above image the B&W negative was scanned as if it were a full color positive. Scanning in this way prevents the image from being automatically value inverted by the scanner. During the scanning process the negative is placed in a negative carrier that holds it in position beneath the backlight and neatly crops the unexposed areas at the edge where the film was covered by the holder during exposure.

If anything the scanned negative looks worse than it did against the backlight. There seems to be even less contrast than before.

4x5 negative, inverted and white balanced by Photoshop

The White-Blanced Positive

Now that we’re in the world of digital photo manipulation there’s no limit to what we might do with the image. In an effort to keep things simple the above scan was simply value inverted and then Photoshop was allowed to automatically balance the white. This relatively minor manipulation didn’t increase the contrast of the image, or significantly extend the tonal range. For a first go at a 4×5 negative it’s alright but as photomicrography goes it’s a failure. Because it’s been scanned as a full color image rather than a black and white image, one could go to the small trouble of manually setting the white balance by selling the tones which should be made white, black, and a middle gray. In my mind excessive manipulation is to be avoided so I won’t bother with that.

Defects

In the Photoshopped positive we can see just how little tonal range the image has. There is strikingly little contrast and the areas that should be a pristine white are middle-of-the-road gray. Additionally, in looking at the tonal difference between the left and right hand sides of the image it’s clear that the illumination was uneven.

Settings

This negative was taken using the 20x objective of the BalPlan microscope. The illumination system was run at 9v and no special care was taken to first arrange for Köhler. Only a frosted glass filter was placed in the light path. The shutter was operated at 1/125th of a second, the fastest speed available on the B&L Integrated Camera System II. It was developed in D76 1:1 for 10 minutes under continuous agitation.

Proposal

Working from the assumption that the negative is over-exposed steps will be taken to address the issue. The exposure will be lowered by drastically cutting the power of the illuminator, dropping the voltage by half to 4.5v while keeping the shutter speed the same at 1/125th of a second. Because of the significant decrease in color temperature this will cause in place of the plain frosted filter in the light path a frosted day-light glass filter will be used. In an effort to increase the contrast the negative will be processed in an undiluted solution of D76 for 12 minutes with continuous rotary agitation. According to available information a less dilute solution of developer, and longer developing time will produce a negative with more contrast.

Tray Processing

What about tray processing the negative? Arista EDU Ultra 100 B&W film is panchromatic. Panchromatic film is sensitized to all wavelengths of light meaning it would require processing in an open tray in total darkness. I don’t know that I’m up for making my first attempt at tray processing under total dark conditions. Whats that, do it with a light on then? Sure! Why not?

Fogged panchtomatic negative developed in open tray under red 7.5watt bulb

Fogged Negative

The negative above was processed in open trays under a red 7.5 watt bulb. The outlines of a few diatoms are just barely visible. Note that there is no perfectly clear unexposed area at all on the negative, not even at the edges where it was covered during exposure. When the entire negative show some level of exposure it is referred to as fogged. This is a particularly heavy example of fogging and is caused by exposure of the film to wavelength of light to which it is sensitive prior to the end of fixing.

Large Format Photomicrography part: VII

In the previous post I wrote a little about the options for processing chambers and in the post before that a little about the chemistry that does the work. Now to put that to use!

The Plan

Out of something like home team spirit I’ve decided to go with chemistry from Eastman Kodak. Nothing exotic or home-made; all these chemicals are exceedingly well understood, readily available, economical and are rather more forgiving than some of the film processing guides out there represent. In fact, most photographic chemistry is surprisingly forgiving-there’s just a drive for consistent results that pushes folks into a corner and makes many too afraid to try or to color outside the lines. Everything will be happening in a daylight color print drum.

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Everything needed to process

Film

The film I exposed earlier is Arista EDU Ultra 100 ISO 4×5 black and white. In photomicrographic use lower ISO speed is generally a better bet than higher because it will exhibit a smaller grain size and permit the use of the longer exposures that provide good contrast in this the world of photomicrography. As a rule it’s also far less expensive than ISO 20 film. Many of the older texts on photomicrographic process recommend speeds as low as ISO 7, or even 4!

Developer

I’ll use Kodak D76 as my developer and dilute the working solution 1:1 with tap water for a 10 minute processing time. Kodak D76 is a classic and versatile black and white developer that does just fine in a tray, drum, or tank. What’s more, it’s so widely available that a quick search can usually turn up an account from someone using it in exactly the way a novice is considering. There’s data and recommended processing times for just about every film out there. Guides on stand developing (where there’s no agitation during development), continuous agitation, and drum processing abound. There are dilution possibilities for almost every need and temperature recommendations for nearly any conditions.

First about dilution. One can use D76 straight and undiluted or water it down to varying degrees. As a general rule the less diluted the working solution the faster it acts on the films emulsion. However, It would graph as an asymptote and concentrating the solution beyond a certain point will not decrease the developing time simply because the developer won’t have sufficient time to act upon the films emulsion. Conversely, diluting the solution too much will not extend the processing time beyond a certain point. Put another way, if making an acetic acid and sodium bicarbonate (vinegar & baking soda) volcano one will reach a point where using less acid will not make an eruption just as one will reach a point where using more will not make the reaction continue. For the most part one will not notice a difference in film processed in straight D76 for 6 minutes or D76 1:3 for 12 minutes (some people will claim to see a huge difference but will then proceed to upload zero examples or show anyone their proof). Is there a difference? Yes, one of those is going to look slightly different but unless your pushing the limits making a poster sized enlargement from a 35mm negative and using a hand lens to examine it, you won’t notice it and there are other things that will have a much bigger impact than dilution. Pick a dilution that sounds good and go with it, this is about just seeing if I can do this not if I can make a negative without grain detectible under a hand lens!

As for temperature there is an insane amount of importance placed on it, why? Well anyone who took a chemistry class knows that temperature has a big impact on reaction time, and film processing is all about chemical reactions. The rule of thumb is hotter temperatures cause faster more complete reactions than colder temperatures which still happen but happen slower and are less complete. Some folks read that the packet of developer says processing takes 9.5 minutes at 20˚ C when diluted 1:1 and think that’s a rule. It’s not, that’s just a starting point. That’s just saying that if you always develop under those conditions you’ll always get the same results from an identical negative.

There’s all manner of water baths and water bath heaters that keep ones chemicals at just the perfect temperature for processing. Those would be handy if they were portable but for the most part modern room temperatures are depressingly stable. 20˚ C just happens to be magic, it’s the so called “room temperature” of science. So what temperature should one strive to process at? Why your own personal room temperature of course! Don’t bother with folks who put extreme emphasis on temperature, and don’t bother pointing out the fact that a thermometer that isn’t regularly calibrated can be off by as much as 5˚ C. Is getting a consistent temperature ideal? Yes. Is consistency important? Sure. Is it super-ultra-stress-about-it-so-much-you-don’t-even-try important? Hell no! There’s no need to needlessly complicate this, look up the time recommendation for D76 for whatever room temperature happens to be on site and use that.

Stop

Water water water! Distilled? No! You’re not pumping your drinking water out of a limestone cave, it’s not going to leave hard water concretions all over the place after a minute long bath! Set aside a jug or two of water and let it come to room temperature or just get good at adjusting the taps on the sink. A minute of processing in a plain water stop bath is perfect.

Fixer

Kodak Fixer (Kodafix, a.k.a. Kodak Professional Fixer). Purchased as a condensed liquid it’s diluted 1:3 for the working film solution and takes from 5-10 minutes according to the bottle. I’ll go with 5 minutes. Mixed from powder it’s used 1:1 as it mixes to make the working solution rather than the condensed stock. Unlike the developer which I’ll discard after a single use (it can be saved and one can add a bit of D76R-the R is for replenisher to get it back to working strength) the fixer will be saved. A given volume of fixer has a given capacity of material that it can fix. This capacity is generally rated in some specific quantity that one will have to use to calculate for their own needs.

A volume of 3.8L of 1:3 dilution of Kodafix has a film fixing capacity of 120 rolls of 36 exposure 35mm film. A single roll of 36 exposure 35mm film has a surface area of 0.0465 m² so 120 rolls would have a surface area of 5.58m² which works out to 8649.017 in² or 432 sheets of 4×5 film, if I mix up the whole bottle. My little 4×5 print drum takes not quite 50ml of solution. So 432/3800=x/50 meaning I can mix up 50ml and use it for 5 and a half sheets (5.68 sheets of 4×5 film for every 16.7ml of condensed stock solution).

Fixer should be replaced when it takes twice the time to clear undeveloped film that it took when it was fresh. What does that mean exactly? Take a strip of film cut from a fully exposed but undeveloped sheet (or the leader cut from a shot but unprocessed roll of 35mm) and drop it into your fresh working solution of fixer. Time how long that piece of film takes to turn clear, and that’s the clearing time. The fixing time is double the clearing time. After you’ve processed a whole bunch of film test it again for the clearing time. It’ll be longer than it was when you started but probably not double the original clearing time. Double the new clearing time to get your new (slightly longer) fixing time and keep right on going.

Wash

After fixing it’s time to wash it five minutes or so in a plain water rinse is all that’s needed for that. If someone does happen to have particularly hard water, or a very humid environment it can be a good idea to spend $20.00 on a bottle of something like Kodak Photo Flo. A couple of drops in the final water wash will help dry the film without streaks or water-spots. It handle necessary though and is really just a way to sell photography people a surfactant, Worth it though, if your having troubles on that end of things.

Steps

  1. Load a sheet of exposed 4×5 into print drum inside changing bag
  2. From stock solution of D76 make 50ml of working 1:1 dilution in a beaker (25ml D76 & 25ml tap water)
  3. From concentrated Kodafix make 50ml of working 1:3 dilution in a second beaker (17ml Kodafix & 33ml tap water)
  4. Pour working solution of D76 into drum
  5. Turn drum on it’s side to release developer and roll drum back and forth on table for 9.5 minutes
  6. Hold drum upright over sink to drain
  7. Turn on the sink taps and let the drums internal cup fill with water, release the water roll it around briefly before allowing the water to drain, repeat as many times as possible for 1 minute
  8. Drain water from drum
  9. Pour working solution of Kodafix into drum
  10. Turn drum on it’s side to release developer and roll drum back and forth on table for 5 minutes
  11. Hold drum upright over sink to drain
  12. Remove funnel cap (and cup) from drum and throughly rinse film under tap water at sink for 5 minutes (alternatively place film in high volume water bath for 5 minutes)
  13. Hang film to dry

Timed Audio Guide

The above process is nice if you can remember it or read along as you go. For anyone who’s going to be giving it a go in a darkroom with trays (or anyone who just want’s to hear me ad-lib the whole process) I’ve created a timed audio file. You’ll need to start with the working solutions measured out if your using the file with a drum or tank, or already in trays if your going that route. Everyones phone has a voice recorder theses days so you can of course make your own timed audio guide if you’re using a different bunch of chemistry, film, or temperature conditions. That lovely busy-bee sound you hear is me being lazy and using a motor base to do the rolling of the drum.

Play it in your browser above or here’s the link to download as an m4a, and here’s the link to download as an mp3.

Next time: scans of some negatives and notes on my attempts at tray processing. -K

Large Format Photomicrography part: VI

Apart from the chemistry, (and it’s worth knowing that’s the lingo) in order to do the actual processing one will need something to do the processing in. In keeping with the philosophy that the best material is worthless if one hasn’t got it I’ll begin with something that’s likely to be on hand, and move forward from there.

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Film processing tanks

Tray Developing

No need to rush out and order some fancy perfectly size plastic or enamel developing tray, a cheap plastic storage box or even a Chinese take out container can serve as a processing vessel. If going this route one will need three trays to make things easy, and a darkroom. Don’t discount this as an option if a darkroom isn’t available. Working at night can go a long way to solving most of the troubles of setting one up and a roll of aluminum foil and some masking take can handle the rest. There isn’t really a need for a safe-light but it goes a long way to making things easier. There’s no need to buy a fancy or expensive safelight either, a can of red spray paint can transform a standard lightbulb. The ubiquitous smart-phone displaying a full screen solid red picture works just as well, it’s a little safer to just adjust the display settings for a deep red tint though.

One will have to figure out the volume of chemistry to get a centimeter or so of depth in the trays. Additionally, a pair of tongs or rubber gloves will need to be used for shuffling the film about in the tray and moving it from one to the other. Some photographers wouldn’t touch tray processing for anything and others wouldn’t dream of doing anything else. It can be pretty daunting to start with tray processing and the need for a darkroom can turn a great many people off.

Darkroom Film Tank

If trays aren’t to ones liking, a film tank will do. These are basically deep open tanks into which one dips the film after loading it into a specialized hanger sized exactly for a sheet of film. Darkroom tanks require significantly more chemistry than trays but have a smaller footprint and due to the lower surface area they expose the chemistry stays fresh a bit longer than an equal volume in a shallow tray-great news if you’re running a school darkroom on a shoestring. The hangers keep the individual sheets of film from touching and run a dollar or two a piece on the second hand market.

Daylight Film Tank

Particularly dexterous photographers can process as many as 10 sheets of film in trays at once without any issues, other folks struggle with scratches from a single sheet. Just as one can process 36 exposures of 35mm film at once in full daylight provided it’s been loaded in the dark, so can one processes a number of sheets of 4×5 in a daylight cut film tank. There are a number of vintage and modern options when it comes to these sorts of tanks and they run the gamut as far as quality and cost goes.

Downsides to daylight cut film tanks abound. The vintage ones are inexpensive but leak like nothing else and may be rather incomplete. They require a heroic volume of chemistry, many take 2 liters or more. New systems, such as the Combiplan, tend to cost a ridiculous amount for what they are but don’t leak and use far less chemistry. All of these will be a struggle for anyone working in even the largest changing bags. Still the old tanks from Yankee hold 10 sheets and only run $20.00 or so second hand, just don’t make the mistake of shaking them all around like one would do with a 35mm tank.

Daylight Print Drum

Ostensibly made for processing prints, daylight print drums are available in a range of sizes, including 4×5. The small black tube in the photo above from Ilford Cibachrome is only a bit larger than an empty roll of toilet tissue and can handle one sheet of film at a time. Larger drums can handle multiple sheets and different brands have different takes on the internals with channels and grooves to keep multiple sheets from overlapping or knocking around. As new old stock one can expect to pay $10.00 or so (including pack and post). Daylight print drums use very little chemistry, are inexpensive, and can be quite convenient provided one doesn’t need to process a couple dozen films in an hour.

At their most basic processing drums of this sort are a hollow tube with a light-tight drain on on side and a light tight funnel and cup combo on the other. Hold the drum vertical and pour the chemistry in to the funnel where it gets caught in the internal cup. Tilt it onto it’s side and roll it back and forth on a table to start processing, or spring for a motor base that will rotate it at the push of a button. A couple hardware store casters screwed to a scrap of wood will do for a manual roller base if space is tight. Flip it on it’s end to drain the chemistry and move on to the next step.

Daylight Cut Film Drums and Tanks

There’s a whole range of brands out there that can handle cut films. Some of them work more like the 35mm daylight film tanks that look and work pretty much like a cocktail shaker and others look more like a daylight print drum. They are all hopeless overpriced for anyone who doesn’t just want to dip a toe in and test the water. Get ready to shell out $300.00 or so just for a Jobo tank (never mind the film insert) or any of a dozen exotic film holders that will fit in a standard three reel 35mm film tank.

The Jobo’s are a breeze to load up and use while most of the insanity that they call 4×5 “reels” are variations on the trials of Hercules, hard enough in the light and true madness in the dark. They require a motor base in most cases or a bit more thought out placement of casters for manual rolling because of their more complex construction-the chemistry might not be evenly distributed if it’s just rolled on a table.

Daylight Roll Film Tanks

Grab a plastic two reel Paterson super system 4 and search the web for “4×5 taco method”. It’s easy, it works, it’s affordable, and if one picks up two multi-format plastic reels with it one can process their own 35mm and 120 roll film too. This is the way to go for anyone who isn’t adventurous enough for trays and is to wary (or just unlucky) on the second hand market. Anyone lucky enough to have an area photography store can pick up the gear for this new in store while everyone else can support the few stores still out there by buying it new from a website and having it shipped.

Conclusion

There is an option out there for anyone who needs one. The goal here is just to get one print so the daylight print drum is the way to go, no darkroom required and it’s small enough to fit with room to spare even in a small changing bag.

Don’t get discouraged if you were hoping to see me flub an attempt at tray processing! I just hung a few black sheets around my basement utility sink and I’ll be flailing around in there as well!

Large Format Photomicrography part: V

Previously the general program and goals were covered. After which a ground glass focusing screen was cobbled together. A plan for a home built 4×5 photomicrographic camera was outlined, all before finally exposing a sheet of film. This is the point at which enthusiasm begins to come up against the fear of chemistry and nyctophobia that plagues analog photography. Whatever else the writer might be, he is certainly not a chemist, a well-informed photographer, or particularly strict in his adherence to procedure. Fortunately, apart from all that, he is as well not one for whom fear of failure (or failure out-right) has ever been dissuasive!

Now, one could without too much searching locate a mail-order film processor who would happily provide a mailing label and some assurance. Safely packing off ones exposed film (still in holders) to an accomplished film processing service is not for everyone however, and potentially as expensive as processing it ones self. There are a few choices to make, and some purchases that will likely need to be made.

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Assortment of powder and liquid photographic chemicals

Here’s what one is going to need:

  1. Developer
  2. Stop bath
  3. Fixer
  4. Developing chamber

That’s all, four things, simple. Developer and fixer can be daunting but it needn’t be, it’s available as kits from all manner of specialty shops on-line, the only hard choice is what to get. First one will need to decide to go with color or black and white. Obviously this is contingent of the film that was used in the earlier posts but one can always choose to color outside the lines and cross process (develop film in alternate chemistry). Black and white processing is simpler so one can’t go wrong with that as a first choice. There’s all manner of options even after one limits the choices to black and white developers but one can generally put them into two very broad categories based on the manner in which they are sold, those that come as dry powders and those which come as a liquid. There are positives and negatives to either but the chief among them is generally perceived to be lifespan.

Developers that are sold as a liquid may be provided as a single concentrated solution or a couple concentrated solutions. Those of both types are added to a prescribed quantity of water to make what is called a working solution that will be the actual developer used. The developers that are sold as a powder have an indefinite shelf life, until they are mixed and the same may be said for most liquid developers. So-called Pyro (PMK or Pyro-Metal-Kodalk) developers generally have a phenomenal shelf life and as a single use developer (working solution discarded after use) may be a good choice for someone who expects to only process a limited number of films in a given year. Regrettably, even as developers (essentially all of which are toxic) go Pyro developers are on the far end of the safe/environmentally friendly spectrum. Pyro developers also impose limits on the stop bath and fixer that one may use in a later step. A concentrated liquid developer such as Ilford’s Ilfosol-3 may be a better choice for anyone who wants to keep their options open.

Powder developers are well worth consideration. One of their modern-day assets, and one which should not be overlooked, is the ease of acquisition. All powder developers are freely shipped to any mailing address through the normal mailing services, they require no special hazard labeling, address requirements, or delivery services (a number of liquid developers are disallowed by the USPS and may not be shipped to PO boxes or residential addresses). The concern that puts many off of using a powder developer is primarily of shelf stability and mixing. Preparation of the developer from powder is far simpler than one may expect. As most home plumbing can supply water at the recommended mixing temperature an inexpensive pitcher, spoon, and thermometer are all that is required, then follow the directions on the packet. Self stability of the mixed solution may be easily addressed by keeping the mixed developer in full, small, brown plastic bottles-the sort in which hydrogen peroxide is sold are excellent. Most powder developers mix to create a US gallon of concentrate and will fit exactly in four, empty, one quart, hydrogen peroxide bottles.

The stop bath is more restrictive for color film processing and one may employ a plain water stop for most black and white processing. There’s no need to buy a specialty stop bath although of course, it is an option some photographers will never give up.

Fixers are a necessity however, and much like developers are available as both powders and concentrated liquids. Shelf life is generally not an issue with fixers and unlike developers are frequently used for multiple rounds of use before they are discarded. The two primary varieties of fixer are those which are acid and those which are called archival (base). In a general way one can always achieve acceptable results by making use of the flagship fixer made by the same company that produces the developer. Alternatively one is free to make use of the classic standby, sodium thiosulfate, popularly called plain hypo or photographers hypo. Hypo has the particular benefit of being widely and inexpensively available in brick-and-morter pool and hot-tub supply stores where it is sold as a chlorine reducer.

One may as well employ a dedicated final wash but much like the stop bath it is a matter of personal choice. To many it’s an unnecessary complication that is best when in the form of plain tap water.

This is already too long so next time, developing containers! -K