A Non-Silver Manual: Vandyke brown

The chapter called “Vandyke brown” of Sarah Van Keuren’s book “A Non-Silver Manual: Cyanotype, Vandyke Brown, Palladium & Gum Bichromate with instructions for making light-resists including pinhole photography”.

Read the previous section of this book.

Over the years I have seen many stunning vandyke brown prints by undergraduate and graduate students working in non-silver. Sometimes a fortuitous coupling of light-resist and process occurred. Other times the student cared and learned enough to craft a negative that would bring out what the process has to offer.

This process can render an image in rich browns that record every nuance of density within a light-resist. But it can also deliver a flat gray-brown print, mottled and disappointing, when used with a low contrast negative (or even a ‘normal’ negative) and/or improperly handled.

Characteristics

Printed with the appropriate negative, vandyke has the tonal range of platinum or palladium. All three of these processes have, within their characteristic curves (a succinct visualization of the amount of printing-out of a process per unit of exposure), extensive straight-line segments along which there is reciprocity of response in image tone to unit of light. A self-masking characteristic of vandyke (along with platinum and palladium) allows a long exposure of dense highlights without the loss of shadow detail that occurs with silver prints. Such a true positive from a negative is possible because vandyke prints out somewhat during exposure instead of only during development: shadow areas turn a reddish brown which acts locally as a filter or mask to prevent further exposure. Although cyanotypes also print out (much more, actually) during exposure, the purple-blue-gray-green colors they turn do not hold back actinic light and shadows do block up. Vandyke, palladium, and platinum are self-masking; cyanotype is not.

Although much of the vandyke image is formed of silver, this process is in the iron print category along with cyanotype, platinum and palladium. In all of these processes, iron salt in a ferric state is reduced where it is struck by actinic light to become ferrous. In a vandyke brown print, silver nitrate lying in contact with the newly ferrous iron is reduced to visible metal during development in a weak fixer. Unexposed iron salts cannot be etched away, as they can be in platinum and palladium, because an acid etch would destroy the silver image. (Only the so-called ‘noble’ metals such as gold, platinum and palladium are relatively insoluble in acid.) Over time, residual iron salts that weren’t washed out may reduce, giving off-white tones to the highlights of the print. (It is possible that EDTA salts in water could work as chelating agents to remove residual iron salts, but preliminary tests by photographer John Woodin and myself have not confirmed this.) Over the years the vandyke brown process has been referred to as ‘the poor man’s platinum print’ because of its beautiful long tonal scale, but it has also suffered from concerns about its stability over time. It would be wonderful if someone somewhere would test the stability of vandyke on a range of papers with a range of clearing agents in a more rigorous manner than we have had the time to do. It has to be someone who is in love with the look of the process who wants to make sure that image highlights do not darken and that the silver forming the rich brown image remains a rich brown. I could imagine being such a person if I weren’t already committed to doing my own work in cyanotype and gum bichromate…

Paper and Cloth Supports

Arches Platine, Arches Cover, Bergger Cot320 (available from Bostick & Sullivan), and Strathmore single-ply series 500 papers (both hot and cold press) print with higher contrast and clearer highlights than a soft paper like BFK Rives which absorbs the vandyke solution and doesn’t easily release it. But plenty of good vandykes have been made on BFK and on many other kinds of paper. Impurities in some papers react with vandyke solution to produce unwanted spots or streaks, sometimes light and sometimes dark. With vandyke we are even somewhat restricted with paper size since our designated processing trays are approximately 13˝ x 16˝; however, larger trays that have been used for cyanotype or gum may be used if they are swabbed out and rinsed thoroughly.

Vandyke prints richly on natural fibers like cotton, silk, rayon and linen. Unfortunately, in our non-silver darkroom we have no place to safely hang large pieces of cloth sensitized with vandyke brown solution. The silver nitrate in the solution is too burning to the skin and blinding to the eyes to take any chances with someone who might come into accidental contact with wet sensitized cloth hanging in the darkroom. It is possible in our darkroom to print on cloth smaller than 13˝ by 16˝ that can be taped to pieces of glass or plexi before applying vandyke solution and then slid into the drying rack and dried on that surface. A certain amount of the solution will soak through the cloth onto the glass or plexi and should be cleaned off thoroughly when the cloth is removed since next person who needs to use the surface may not recognize vandyke solution on the surface and could be hurt.

Safety

Before reaching for the single bottle of vandyke chemistry, put on gloves! If traces of silver nitrate are on the bottle, your bare fingers will be stained and burned. If you should get it on your skin, wash the afflicted area with cool water. Protect your eyes by wearing glasses instead of contact lenses. Consider using goggles or a face shield if you don’t wear glasses — at least until you feel confident applying the vandyke solution. If any solution ends up in your eye, use the emergency eyewash station or flood the afflicted eye with water and seek medical attention. Clean up all surfaces. An invisible film of silver nitrate left on the coating table could hurt someone else.

Mixing the Chemicals

The formula for making one quart of vandyke brown solution is:

29 grams (≈ l ounce) silver nitrate
90 grams (≈ 3 ounces) ferric ammonium citrate
15 grams (≈ 1/2 ounce) tartaric acid

Pour each of the three chemicals into 3 separate labeled containers (used only for this purpose), each containing 8 ounces (236 ml) of distilled water. (It is more important with vandyke than with cyanotype or gum bichromate solutions that distilled water be used since the chlorine in tap water can react with the silver nitrate.) Stir each chemical into its 8 ounces of water with a clean glass rod or plastic utensil. Pour the ferric ammonium citrate and tartaric acid solutions together into a quart measuring pitcher reserved for vandyke only. Wearing gloves and protecting your eyes with glasses or goggles, slowly add the silver nitrate solution to the pitcher while stirring. Add enough distilled water to make up 32 ounces of solution. This solution, stored and labeled in brown bottles or dispensers covered in black tape, has a shelf life of 6 months to a year or more, probably depending on storage conditions — a cool, dark storage area is best. After about a year the solution may no longer be able to produce rich continuous tone but still can be used for graphic high-contrast images. Eventually, most of the transparent silver salts will precipitate to the bottom of the bottle in gray flakes and chunks of metallic silver and your print will consist mostly of ferrous ammonium citrate, i.e. rust.

Contamination

Full-bodied tone can also be lost through contamination, a true source of woe for the printer. Vandyke solution reacts with metal, so steel trays and brushes with metal ferrules should not be used. The sponge brushes used for applying vandyke solution should be kept separate and not used for cyanotpe or gum bichromate. Traces of potassium ferricyanide or dichromate in the brush used for vandyke will weaken your print. Your trays should not have traces of these chemicals either. You may need to change the water in the final wash tray if it has been used for cyanotype, gum or palladium.

High Contrast Negative Required

A last warning harks back to the density of your light-resist. Thin negatives yield muddy prints. The tonal contrast of vandyke as a process is very low, equal to that of grade 1 or zero enlarging paper. This means that your negative needs dense highlights and open shadows to print a full range of tones. Without dense highlights, in the time it takes to expose to print rich shadows, your highlights will have become too dark.

One of the advantages of platinum/palladium is that you may vary contrast somewhat. With vandyke you have only low contrast. You can make your negatives denser by prolonging development or using a more concentrated developer — but simply overexposing a negative will result in a negative that is dense in highlights and shadows, still a low contrast negative. A concentrated selenium solution may boost contrast by attaching to the silver on the negative and giving it a reddish cast, but to use a heavy metal, that is toxic for the human who uses it and for the environment that absorbs it, is to be avoided if possible. Nowadays, instead of using selenium, I would recommend scanning the thin negative, boosting contrast through Levels or Curves in Photoshop and producing a desktop or imagesetter negative that fits the vandyke process. Traditional darkroom photographers are accustomed to finding a grade of photographic paper (or the appropriate filter with multigrade paper) that will give the best rendition of a particular negative. Non-silver photographers often have to craft the large negative to work with the particular non-silver process, especially when printing in vandyke brown. If you have a small format negative that you need to enlarge to print in vandyke there are strategies for boosting contrast that are described in the chapter on “Enlarged Negatives”.

Coating and Drying the Paper

When ready to print, tape your paper to a clean surface so it won’t slide around while you’re brushing on the solution. The coating may be done by tungsten light (such as a 60W bulb several feet away) or by dim daylight. Red or yellow safelights are not needed and pose a safety hazard since the yellowish vandyke solution cannot be seen in such light. There are two basic ways to apply the vandyke solution. The one that I favor is to pour a small amount of the solution into a clean dedicated container and dip into it with a 2˝ Poly-Brush (rather than the finer Foam Brush 8505 that picks up paper fiber). This is a more painterly approach. Avoid brushing to the edges of the paper in order to provide a safe handling margin and to prevent contamination of the drying screen. The second method is to dribble a thin line of the watery solution directly from the dispenser bottle along an end of the paper and swiftly but carefully pull it across the image area with your sponge or haké brush or with a glass or plastic coating tube. Have a dry sponge brush on hand, however you coat, to absorb excess solution. Don’t let the solution lie in puddles or run off the page. If it does dry in puddles you will find that the excess will mask the print and leave white areas where you would expect dark tones.

If the paper you are using has a tendency to curl (as happens with single-ply Strathmore 500), tape it to a piece of glass or plexi, sensitize it, and slide the ensemble into the drying rack. After a minimum of 10 minutes in the dark drying rack, remove the ensemble and, while the paper is still taped down, complete the drying with a hairdryer. If the coating is not completely dry when you make the exposure, dark gray/black streaks will appear on your print — so be sure to feel the back of the paper for cool dampness and flex the paper to see if the center is puffed out with un-dried vandyke solution and can’t easily flex back and forth. Also, while flexing the paper, listen for a crackling sound that indicates dryness. Do not touch the sensitized surface of the paper for the sake of your image as well as your skin.

Exposure

A vandyke print takes much less time to expose than a cyanotype. A sufficiently exposed vandyke will look quite underexposed before processing whereas a sufficiently exposed cyanotype will look very overexposed. If you are making a vandyke by inspection, expose only until the upper middle tones barely begin to show detail. The print darkens tremendously during both processing and drying.

Test strips are recommended. Be sure to use the same paper that will be used for the final print since the rendition of your negative will vary depending on the kind of paper you print on. Before sensitizing the test sheet, place the negative beneath the paper on a light table and mark areas and times of exposure in pencil using a straightedge. Each exposure on the test strip should include both dark and light critical areas of your image so that you may evaluate both shadow detail and highlight separation. You cannot judge a test strip until it has been processed and dried, since it darkens as it dries.

Processing the Print

Three trays are required for processing your vandyke print. The first two should be used exclusively for this process and should be labeled accordingly.

A tray labeled First Immersion for Vandyke contains cool tap water.

A second tray labeled Diluted Fixer contains 60 ounces cool tap water and 3 ounces paper strength fixer. Paper strength means fixer diluted to the point at which it is used for fixing a normal silver gelatin print. The traditional fixer for vandyke is pure sodium thiosulfate, first mixed l cup to a quart of water and then diluted l:20. We use Sprint fixer without the alum hardener. Whatever kind you use should first be diluted to normal paper strength and then diluted again: one part to twenty parts water. Undiluted regular strength paper fixer would have a bleaching effect on the very finely divided silver that constitutes a vandyke image. (I find it interesting that the smaller the grain of silver, the browner the color is, and, conversely, the larger the grain, the cooler and blacker it looks.) The diluted fixer, however, is exhausted quickly and, to be on the safe side, should be replaced after every 8˝ x 10˝ print plus test strip (or every four 4˝ x 5˝ prints) that goes through it — or at the least, in time of drought, after every two or three 8˝ x 10˝ prints.

We used to include a third tray, labeled Fixer Remover, which contained a regular strength working solution of a washing aid such as is made by Sprint (mix stock solution from the cubitainer 1:9 with water) or Perma Wash (mix 11/2 oz. with 2 qts. water). This reputedly helped remove traces of fixer from your print and shortened washing time. It was used for the entire session and dumped only at the end. Students tended to go through the expensive fixer remover very quickly, mixing it too concentrated or dumping it prematurely. Since vandyke is not an archival process to begin with and since cotton paper clears much faster than silver gelatin paper and since there is online precedence for omitting this step, we decided to do the same with no observable difference thus far.

The current third and final tray is required for washing the print in cool tapwater. It is elevated, usually on top of an upside-down tray, and fitted with a Kodak tray siphon that injects clean water from above and draws out contaminated water from below. If this water has been used for washing prints done in cyanotype or gum, your vandyke print is likely to have some of its richness bleached away. So before you wash your vandyke, carefully remove the tray siphon, bail out and dump the contaminated water, drain the tray, wipe off slime and sludge with paper towels, rinse the tray, replace the tray siphon and refill the tray with cool water.

After exposure to actinic light, slip the printing paper, face up, into the tray of water labeled First Immersion for Vandyke. Cover the surface of the print with water. With tongs, or wearing gloves, lift the sheet and slip it, image-side down, into the water. Heavy unexposed iron and silver salts will drift to the bottom of the tray. Agitate by rocking the tray and laying the print alternately right-side-up and upside-down for two minutes. Then lift the paper out and let it drain. Next slip the print into the Diluted Fixer tray face up, cover with liquid and agitate. You will see the image turn from a rusty reddish-tan (the printed-out iron salts) to rich chocolate brown as the silver salts link up with the exposed ferrous iron salts and are reduced to visible metallic silver. Lift the print and replace it face down while continuing to agitate. After two minutes, lift and drain the paper.

The optimum time for the final wash of a vandyke doesn’t seem to be common knowledge but in a class situation we average about l0 minutes. A thick, soft paper like BFK Rives will take longer to wash than a thinner, harder paper. Keep an eye on single-ply Strathmore 500 paper as it washes to make sure it doesn’t crimp or buckle. Do not use two-ply Strathmore 500 because its glue is acidic and can mottle the image and yellow the paper over time.

Test strips do not need as long a washing as prints but should be completely dried for evaluation, not just because of normal dry-down but because the brown of the vandyke gets darker as it dries.

Cyanotype with Vandyke

Cyanotype solution brushed over a processed vandyke will have a bleaching effect. This is not really a surprise since the potassium ferricyanide half of cyanotype chemistry is a potent silver bleach (as well as the source of blue in a cyanotype). If the initial vandyke print is a very strong image, the cyanotype solution will bleach and replace the darkest brown areas with blue only where they are re-exposed to powerful actinic light. This means that a positive image in vandyke could survive on paper with its negative image printed over it in blue. Interesting white lines and complex mossy green effects occur in continuous tone areas where the processes compete. But if the positive image were reiterated in cyanotype directly on top of the positive vandyke, the brown might vanish entirely and you might as well have printed a cyanotype to begin with. (The same goes for printing vandyke on top of cyanotype and I don’t have, at this time, an explanation for why cyanotype yields to vandyke.)

Read the next section of the book.


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