The VDB (Van Dyke Brown) process, like the cyanotype, produces an image due to the reaction / reduction of ferric (iron) salt to a ferrous state during exposure to UV light (a Sir John Herschel Argentotype technique from 1842). The Van Dyke process employs a sensitizer formula consisting of ferric ammonium citrate, tartaric acid, and silver nitrate and is wash-developed in distilled and fresh water. The Van Dyke print is then either toned in one of several toning options, for color and archival reasons, or immediately fixed in a 3% sodium thiosulfate bath and washed for permanence… an often oxymoronic term when applied to Van Dyke because of its long history of dysfunctional processing directions passed along for decades in many alternative process texts and teaching. This problem, compounded with inadequate final washing, has led to a lasting perception of impermanence for this under-appreciated process.

The century long rap against this process, under any of its names, has been its lack of archival integrity. Most of this reputation is due to the major problem that plagues much of alternative process technical history… that one piece of bad information is like a line of bad genetic code that just keeps being passed along, from one generation to the next. That’s just one of the problems. The others revolve around the failure to completely remove the residual iron compounds from the paper, fixing recommendations that employed concentrations that were far too strong, and that call for immersion times that were far too long. Still another issue involves dealing with the silver chloride or silver chloramine formed in the wash-development. Chlorine will react directly with image silver to form silver chloride. The thiosulfate fixer is then needed to remove the silver chloride trapped in the paper’s fibers, and this step has to be done well in order to prevent problems down the road for the print. For such a simple process, and it really is almost as basic as the cyanotype, it has truly been an un-loved one. This is unfortunate because it is really a lovely technique with equally beautiful coloration.

The brownprint’s sensitizer is similar to the Van Dyke’s, except that it incorporates oxalic acid in place of the tartaric acid, (a chemical often employed to assist in keeping highlights from getting muddy). The brownprint also requires development in a borax and water formula versus the water-only wash-development required in its Van Dyke cousin. The brownprint’s Borax developer is highly alkaline and that fact leads to the formation of iron hydroxide (close to being rust but wet) is quite difficult to remove. However, should you want to try it, just employ the salted paper technique of immersing your print in a bath of salted water that has been made slightly acidic, lowering its pH, with the addition of a healthy pinch of citric acid. This should fix the problem if your water is alkaline. The brownprint is the least commonly practiced among these three kallitype options. More on this idea later in the fixing instructional stages of the Van Dyke process.

You will notice that when a Van Dyke image is immersed in a fixer, the pleasant warm yellow brown colored image that emerged in the wash- development will change to a cool brown. Depending on the strength of the sodium thiosulfate fixer concentration, the print may also begin to show signs of “etching” and image deterioration. As fixing times approach traditional recommendations, more of the image slowly disappears and if the subsequent wash times are inadequate, then the un-removed residual fixer, trapped in the fibers of the paper compounds the problem.  It is important that your prints are not over-fixed due to either concentration or immersion time and that you absolutely clear the paper of all trapped chemistry by the conclusion of the processing sequence.