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How I make Van Dyke brown prints

On this page, I document my way of working in making Van Dyke Brown prints. This page may change over time as I learn new things. Currently (Jan., 2017) I've been making Van Dykes for about two years and have read anything I could find about it online. I have experimented with just about every variable in the process, but there's always room for improvement.

Materials

Chemistry
I prefer to mix my chemistry from stock solutions instead of preparing a ready-made Van Dyke brown solution. I found that a mixed Van Dyke Brown sensitizer in my situation doesn't keep as long as others assert it will, even if stored in a brown glass bottle. Precipitate does form and there is silver plating after a few weeks/months on the inside of the bottle and the sensitizer won't achieve good contrast and dmax after some time, so I gave up on mixing larger batches and mix only what I need immediately before coating. Contrary to what is claimed in some places, I find there is no need to let the sensitizer 'ripen' before it can be used. It yields good dmax and contrast right after mixing. Ingredients

  • Ferric ammonium citrate, 20% solution w/v - it tends to grow mold after a few days. The mold can be scooped out with a small stick, as it tends to form strands/clouds that can be easily removed from time to time from the stock bottle or it can be removed from the mixed sensitizer. I have found no effect of the mold on the quality of the prints.
  • Silver nitrate, 11% solution w/v - silver nitrate forms a white precipitate with just about any impurity in the water or the vessel it is mixed in. I have found no detrimental effect of small amounts of cloudiness of the silver nitrate solution, but I try to work as cleanly as possible. I use decriminalized water for mixing the silver nitrate solution. I use an 11% solution as that also is usable for salted paper prints, so I can use the same solution for both Van Dyke and salted paper.
  • Tartaric acid, 8% solution w/v - citric acid can also be used, but I find that tartaric acid makes the prints a little less grainy than high concentrates of citric acid tend to do. The difference is pretty small though, so citric acid can be substituted.
I keep the stock solutions in dripper bottles so I can easily count out the number of drops I need. The sensitizer is constituted as follows:
  • Ferric ammonium citrate 20% stock: 5 drops
  • Silver nitrate 11% stock: 4 drops
  • Tartaric acid 8% stock: 2 drops
Mix the solutions in the order given. When adding the silver nitrate, a white precipitate forms. This dissolves as the tartaric acid is added. More drops of tartaric acid can be added to increase the contrast of the print somewhat. I prefer this over using dichromate, as dichromate seems to reduce the dmax of the final print. It also shifts the tone in the dry print to reddish brown, while without dichromate, a more neutral brown/black tone is achievable. The volume of sensitizer can be adjusted to fit the area that needs to be coated, as long as the ratio mentioned above remains constant (5:4:2). The basic recipe of 11 drops in total coats about 2 4x5's, while a 'double recipe' of 22 drops easily coats an 8x10" area with borders. I can coat 4 8x10's with 33 drops of sensitizer on most papers. Note that some papers are more absorbent than others, which will influence the amount of sensitizer needed.

Paper
Like most alternative printing processes, Van Dyke Brown requires neutral papers that are not neutralized with calcium carbonate, as this will cause the sensitizer to form insoluble salts that cannot be washed out of the paper. The paper has an influence on the final tone, contrast and density of the print, so I try new papers from time to time to optimize results. Currently I use Fabriano Accademia for most prints and Schut Simili Japon or Schut Salland etching papers for special prints. All three papers mentioned are capable of providing good dmax, contrast and can be dried to a fairly neutral image tone. The same is true for the Schut drawing paper (it comes in brightly colored blocks) that I used to use, but it has a bit of a rough surface texture that I don't particularly like, hence I switched to other papers. Most watercolor and etching papers are usable for Van Dyke Brown. Surprisingly I found Fabriano Artistico to give somewhat poorer results in terms of contrast and dmax in comparison with the other papers. None of the papers I have tried so far require a surfactant (such as Tween or Photoflo) to be added to the sensitizer. I try to prevent this in any case, as results without a surfactant tend to be more even than with, in my experience. Plus, the simpler the recipe and processing, the better, as far as I'm concerned.

Coating

I brush coat the sensitizer with a synthetic, decent-quality hake brush onto the paper. I dip the brush in the sensitizer, make one longitudinal stroke, dip again and lay down the next band until I reach the end of the area to be coated. Then I brush in vertical bands without re-dipping the brush, followed by horizontal bands. By that time, the sensitizer is usually brushed out very evenly. The result is a slightly shiny, pale yellow-green coated surface. I then let the paper lie for a minute to allow the sensitizer to soak into the fibers. Next, I dry the paper with a hairdryer. I found no need to use the cold setting on the hairdryer, as the warm air does not appear to cause any noticeable fog. Drying the paper this way takes only one or two minutes. I coat under my regular lighting, which is a mix of white fluorescents and LED lights. I found no adverse effects of this kind of lighting, so there's no need to work under red darkroom lighting. Coated paper can be kept for a few hours; it probably keeps well for up to 24 or 48 hours, but I always coat just before printing and only coat what I need for the next batch of prints I will make immediately. When keeping the coated paper too long, it starts to fog, which can be seen as it starts to turn tan and later brown (auto-exposure). It becomes unusable at this point.

Exposure

Negative
I only use silver negatives for Van Dyke Brown. I have used inkjet printed 'digital' negatives in the past, but these required too much boosting of contrast in the print and never yielded prints with good dmax for me. Also, I found the inkjet artifacts (the characteristic dots and sometimes artifacts from transport rollers and the like) annoying, particularly in the highlights. I found that it was actually easier to get good prints with 'real' negatives than with digital negatives. As a consequence, I usually print from 4x5" and 8x10" negatives, although I also frequently proof my roll film negatives with Van Dyke Brown. The latter is a great way of making contact sheets, as Van Dyke Brown easily captures the entire tonal range of typical roll film negatives and it's quicker to pull a Van Dyke Brown than to set up for a quick session of silver gelatin printing.

I currently mostly use Pyrocat-HD for developing sheet film as the stain adds extra UV blocking power on top of the silver image, making it an ideal developer for this purpose. Van Dyke Brown requires rather a long tonal scale. When developed in a staining developer such as Pyrocat HD, a negative that prints well on about grade 1 on silver gelatin paper is about right for Van Dyke Brown. With a regular developer, aim for negatives that would print well on grade 0 or even 00 (in other words: way too long-scaled for silver gelatin). With Fomapan 100, a film I frequently use in 4x5", development times are about 16 minutes with Pyrocat HD 1+1+100 (continuous agitation in Jobo processor). Double-sided 8x10" x-ray film rated at ISO 50 requires around 9 minutes with Pyrocat HD 1.5+1.5+100 with continuous agitation in a tray for a good Van Dyke Brown.

Light source and exposure
I use a bank of 8 Philips Actinic tubes of 60cm (18 Watts each, so 144 Watts in total) with about 1 cm (1/2") of space between them and a home-made contact printing frame. I place the print about 10cm (4") underneath the tubes. Exposure times are 3 to 3.5 minutes. Less than 3 minutes tends to not quite achieve maximum black in the print. I sometimes make a mask to get clean borders in the print, which can be omitted if brush marks along the edges are desired. A mask can be cut from Rubylith film, aluminum foil or any other UV-opaque material that is thin enough not to interfere with the contact between the print and the negative.

Processing

Processing consists of three to four stages: washing, fixing, toning (optional) and drying. Toning can be done before or after fixing; I see no difference in the finished print between toning before vs. toning after fixing.

Washing
Washing is required to remove unexposed, excess sensitizer. It is important that the wash water is lightly acidic, as otherwise insoluble precipitates will be formed that cannot be washed out of the print, resulting in fogged highlights and (unexposed) borders. A wash of about 2 minutes with tap water in which 0.1% citric acid is dissolved works well, followed by a 30 second to 1 minute rinse with regular tap water. During the initial wash, watch the unexposed areas of the print (e.g. the borders if a mask is used) and wash until they are perfectly clear.

Fixing
I generally use exhausted film or print fixer, which I normally use for film/prints in a 1:5 or 1:10 dilution; I further dilute the spent fixer about 1:1 with tap water and then use that for fixing Van Dyke Brown prints. Fixing takes only about a minute with constant agitation. Leaving the print in the fixer too long (>2 minutes) can cause degradation of highlights and reduce dmax.

Toning
A variety of toners can be used, such as selenium, iron, thiourea (sepia) or gold. Toners can be used in high dilutions, as Van Dyke Brown prints respond very well to toning. Gold is the most flexible and one of the most archival toners and can yield tones ranging from reddish brown to purple to neutral blue-grey when toned to completion. Every toner requires a slightly different approach and duration, so experimentation is required to consistently get the desired results. Wash the print in tap water before and after toning; half a minute or so is sufficient.

Washing
The final print needs to be washed in (tap) water for an extended period of time to remove all traces of fixer and toner. I was by soaking the print in a few changes of tap water, agitating from time to time. I wash up to a few hours. I have not done any testing on print permanence, but due to the sensitivity to degradation of Van Dyke prints, err to the long side when washing. In my opinion, archival prints can only be made when toning with gold, platinum or palladium. Untoned prints may keep well for a few months or even a few years (who knows??), depending on purity of the paper, framing, wax/gelatin coating and other factors. In itself, Van Dyke Brown is argued to be non particularly archival and my experience so far confirms this.

Drying
The washed print can be dried by suspending it from a clothesline, or it can be dried with forced/heated air (hairdryer). When drying with a hair dryer, the print tone shifts to a more neutral tint. This can be further enhanced by placing the print dry between a few layers of clean newsprint and ironing the print with a clothes iron at its highest setting (no steam). This yields a fairly neutral print tone and excellent dmax. As a consequence, it also makes the difference between toners smaller, as the shift to a neutral tone occurs regardless of which toner (if any) was used. Still, small differences remain visible after drying with a clothes iron, so toning still serves an aesthetic purpose. The dried print can,if desired, be treated with furniture polish or renaissance wax, which can be buffed after applying it for a dull sheen. Several layers of wax can be applied to increase the glossiness of the print, although a high gloss such as with resin coated gelatin papers cannot be achieved this way (as far as I know now). If a more glossy surface is desired, the print can be coated in one or several layers of hardened gelatin or even gum (basically a layer of transparent gum bichromate with no pigment added). This can yield a gloss that is somewhat similar to an air-dried fiber-based silver gelatin print.

Troubleshooting and optimizing

Several problems can occur in this seemingly simple printing process. I will outline a few that I have run into personally that I have been able to resolve.

  • Insufficient dmax - Getting good maximum black can a bit of challenge at first. The following things are essential: (1) sufficient exposure; this requires a long-scaled negative, as otherwise the highlights will turn out too dark. (2) The addition of sufficient (tartaric) acid to the sensitizer. Insufficient acid in the sensitizer results in reduced contrast and lighter blacks (browns). (3) Force-drying (hairdryer and optionally drying with a clothes iron) improves dmax a bit. (4) If no good blacks can be achieved, try a different paper. Some papers work better than others in this respect and it is perhaps the parameter that shows the differences between individual papers the most clearly.
  • Stained/fogged highlights - Again, (1) paper is one variable that can be adjusted to see if the problem goes away, assuming that (2) a negative of a sufficiently long tonal scale is used. (3) The slightly acidic first wash is essential; try increasing the citric acid concentration to 0.2% or even higher if the highlights won't clear, and make sure to was sufficiently long before toning or fixing. (4) If a toner is used, tone after fixing instead of before fixing, as the toner may start toning unexposed silver salts that have not been washed or fixed out yet. If all else fails, (5) check if there's unwanted exposure to UV light occuring before or after the actual exposure. Usually, when working under artificial light, this should not be the issue, but check by coating, drying and processing the print under darkroom safelighting to make sure that it's not UV fog.
  • Contrast is too high or too low - Too low contrast can (1) be resolved by adding a drop of e.g. 0.5% w/v dichromate to the sensitizer, which will boost the contrast considerably, but it will also require longer exposure times. It's also possible to add the dichromate to the initial wash water, but this is wasteful and adding it to the sensitizer serves the same purpose and is much more efficient. (2) Adding one or two drops of additional tartaric acid solution to the sensitizer will also boost the contrast a little, but dichromate is more effective. Too high contrast can virtually not be resolved. The best way to get the right contrast is (3) to make sure that the negative fits the process. Personally, I believe it's best to fit the negative to this printing process instead of the other way around. Contrast adjustment in the printing stage invariably leads to sub-optimal results with Van Dyke Brown, at least in my experience and opinion, even though 'dichromated' prints can still be quite nice.
  • Print tone is too warm or too neutral - Read the tips on drying above. My hypothesis is that faster drying and the use of heat during drying results in the silver particles clumping together and the bigger the silver particles, the more neutral their tone. Conversely, more pronounced color can be achieved by hanging the print to dry and to not use any forced drying.
  • Print is grainy - Addition of too much acid to the sensitizer tends to result in grainy looking prints. Back up on the acid and use dichromate instead if excessive acid was added to adjust the contrast of the print.
  • I don't like brown - (1) Use gold toner to shift the tone to red, purple or blueish black. Alternatively, use an iron blue toner to shift the color towards a blueish/greenish tint, but this requires overprinting quite a bit, as the toner tends to dissolve part of the image. Also, I rarely find blue toning of Van Dykes to give a pleasing result, so I don't bother with it. (2) Make cyanotypes if you prefer a blue image tone, or tone cyanotypes in e.g. coffee or tea to obtain a bluish-black tint. (3) With Van Dyke Brown, palladium or platinum toning can be very effective in obtaining more neutral tones, but this is a costly approach and personally, I don't bother with it for that reason. Learn to embrace the warm colors of Van Dyke brown or look towards other processes!
  • Uneven, striped prints - Coating Van Dykes is relatively easy, but not all coating methods work for everyone and with every paper. I personally find hake brush coating the most efficient and flexible, as a good brush uses little sensitizer and works with just about any paper. However, (1) more even coating can be obtained by using a foam brush instead of a hake brush, even though more sensitizer is absorbed by the brush and ultimately washed away when cleaning the brush. Whether using a foam or a hair brush, (2) always pre-wet the brush and shake off excess water, so that the brush is moist, but not dripping wet. Alternatively, (3) puddle pusher/glass rod coating can be employed, but I personally have never gotten acceptable results this way. Others get great results this way though, and actually prefer this approach over brush coating, so it's worth to give it a try.
  • The print curls during drying - That's what paper does! (1) Put the print between two layers of newsprint and place a stack of books or the 10 ton weight from the comic books on top of it and leave it there to flatten out for one or two weeks. (2) Ironing the print with a clothes iron will also flatten out a curled print somewhat, but not perfectly, and you have to be very careful not to iron creases into the paper.
  • The print fades after a few weeks/months/years - Van Dyke Brown prints consist of tiny (sub-micron) silver particles that are susceptible to chemical attack from just about any pollutant, whether in the paper or airborne. (1) Make sure to wash thoroughly after finishing the print, and also (2) make sure to use a paper that is as chemically neutral as possible, although manufacturers sadly don't provide much usable information on chemical purity/composition of their papers and any binders or sizing agents used. (3) Toning, particularly in metals more noble than silver, such as gold, platinum and palladium is the easiest (and most expensive) way to dramatically increase the lifetime of the print. A well-washed print that has been gold toned to completion (bluish/grey/black tint) will last for many years. (4) You may try countering any airborne pollutants by 'locking' the print off from its environment. A simple way to do this is by framing it behind glass, although this will only help a bit. It is conceivable that coating the print with wax (Renaissance wax, furniture polish or a bees-wax/lavender oil mixture) helps with this.


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