01-26-2011 FOR INTERNAL USE ONLY Alternative Sources of Photographic Fixer: The Owens Valley TRISTAN DUKE This report was prepared for the Metabolic Studio and in collaboration with the Handmade Film Institute. In the summer of 2010, Lauren Bon’s Metabolic Studio, in partnership with the Handmade Film Institute, began the quest to make a picture not only “of,” but quite literally “out of” the landscape of the Owens Valley. INTRODUCTION Sodium Thiosulfate Chloride, Bromide, or Iodide Salts In the Summer of 2010 Lauren Bon invited Robert Nitrogen (amine) or Sulfur (mercapto) Organic Schaller from the Hand Made Film institute to collaborate Compounds on a film workshop in the Owens Dry Lakebed, in the Ammonium Thiosulfate and Sodium Thiosulfate Owens Valley of California. For that workshop, a photographic developer was synthesized using trona ash Of these only a few compounds are regularly used in collected from the desiccated lake. This report explores photographic fixers. From Strobel, “In actual practice, the possibility of extending this project –to extract however, the choice is quite limited. Ammonia and ingredients for a photographic fixer from the Owens sodium sulfite solubilize chloride but are slow to attack landscape. What follows is a brief overview of fixing silver bromide. Potassium chloride easily dissolves all agents, their composition, and action upon the silver the silver salts, even silver sulfide, but is highly halides. Three fixing agents, sodium thiosulfate poisonous… Organic fixing agents are costly and often 2 (Na2S2O3), sodium sulfite (Na2SO3), and sodium chloride toxic. ” (NaCl) are then discussed with special attention to Given these factors, the most common salts used in potential sources in the Owens Valley. Finally, an onion- fixation are sodium thiosulfate (Na2S2O3) also known as based organosulfur fixing agent is proposed, with hyposulfate or “hypo,” and ammonium thiosulfate preliminary experimental findings. [(NH4)2S2O3]. Rapid fixers are made from ammonium thiosulfate due to the faster action of the same on silver CONSTITUTION OF A FIXER halides. Standard non-rapid fixers are made from sodium If we are to consider alternative sources of thiosulfate which is slightly slower and requires longer photographic fixer we must first understand what a fixer washing times. is, and how it works. A fixing agent or fixer is essential to Strobel describes the action of thiosulfate as follows3: silver halide photo-process. After an image has been 2- - - AgBr + S2O3 → (AgS2O3) + Br developed, a fixer is needed to make the image (Solid) (Solution) (Absorbed complex of (From permanent; without this step the image would continue to low solubility and low solid into darken when exposed to light. A fixer works by stability) solution) dissolving the remaining, undeveloped, light-sensitive silver halide, thereby making the image no longer - 2- 3- (AgS2O3) + S2O3 → [Ag(S2O3)2] sensitive to light. There are several substances which (Absorption (Solution) (Leaving crystal react with the halides to render them soluble. The Focal complex) surface and passing Encyclopedia lists the following silver halide solvents1: into solution) Ammonia or Ammonium Salts 3- 2- 5- Potassium Cyanide (highly poisonous) [Ag(S2O3)2 + S2O3 → [Ag(S2O3)3] (Solution) (Solution) (Solution) Sodium Thiocyanate Sodium Sulfite This three-stage process separates the silver from the halide and carries it into solution, where it then forms a 1 Leslie Strobel and Richard Zakia, The Focal Encyclopedia of Photography. Focal Press; 3rd ed. (1996) 2 ibid p.313. 3 ibid Alternative Sources of Photographic Fixer 2 stable salt with the thiosulfate. Thiosulfates are only (electron donor) in photographic developers and stable in alkali aqueous solution. fixers. In a similar way is applied as preservative to Beyond a halide solvent a fixer will often contain one prevent discoloration in fruits and meats. It is also or more of the following components: found in hot springs and geysers in small quantities. It is a dechlorinator and is used in much the same • Preservative: such as sodium sulfite is used to inhibit way as sodium thiosulfate. sulfur from precipitating out of solution. • pH Buffer: such as acetic acid prevents the solution • Sodium Chloride (NaCl): common table salt is a very from becoming alkaline (and thereby allowing further mild halide solvent. It was first used as a development) while also preventing it from becoming photographic fixer by Daguerre and Talbot in the too acidic for the thiosulfate. earliest Daguerreotype process. There are rumors • Hardener: alum hardeners such as chrome alum that sea water can be used as a fixer, however I did (chromic potassium sulfate) or potassium alum not find any positive results. One site suggested that (aluminum potassium sulfate) are used to make the only the purest “lab-grade” NaCl could be used emulsion more resistant to water and to reduce effectively. swelling when processing at elevated temperatures. • Sludge Inhibitor: boric or polycarboxylic acid The ancient alchemical name for sulfur is brimstone, so named because it could be collected from the brim of For our purposes we do not need fast action, volcanic craters. As it turns out the crater formed by the excessively long shelf life, or large processing power; a Owens Dry Lakebed is also brimming with sulfur. Water simple fixer in alkali solution would seem to suit our samples taken from water sources at the perimeter of the purpose. historic shoreline by the Metabolic Studio show sulfur contents in excess of 33.8g/L. Ryu et al found similar FIXER IN THE OWENS VALLEY concentrations at test locations within the dry lakebed 5 To begin an investigation of “natural sources” of noting the presence of sulfides and sulfates (see figure 1). fixer, I decided to look for instances of the following Ryu cites another study (Friedman et al. 1976), which compounds: found that “The brine pool in Owens Lake is dominated 6 by sodium salts of carbonate, sulfate, and chloride.” The pH readings collected from water samples by the • Sodium thiosulfate: (Na2S2O3) can be produced from the reaction of sodium sulfite and sulfur in boiling Metabolic Studio show that alkali conditions (one of the water and is a common photographic fixing agent. It necessary requirements for stable Thiosulfates) are may be found naturally in hot springs or geysers.4 present. However, the quantities found in such contexts may The high occurrence of sulfur and chloride salts in be very small. It is produced as a waste product of the Owens Dry Lakebed make the presence of sodium sulfur dying processes. It is also used in gold extraction, and leather tanning, and is an ingredient in certain bleaches. It is a dechlorinator and is used to reduce chlorination is super-chlorinated pools, to dechlorinate tap water for aquariums, and to neutralize chlorine in water samples where testing for bacteria will be performed. It is advocated by some naturopathic medicines as a cure for many ailments. • Sodium Sulfite: (Na2SO3) is another sodium salt of sulfur with many similarities to Sodium Thiosulfate. Commonly used as a washing aid or “hypo-clear” in photographic process, sodium sulfite is also a weak fixing agent (especially slow to act on silver bromide). It is often included as a preservative 4 Yasuyuki Miura, Yusuke Matsushita, Paul Haddadb. 5 Ryu et al. “Sulfur biogeochemistry and isotopic “Stabilization of Sulfide and Sulfite and Ion-Pair fractionation in shallow groundwater and sediments of Chromatography of Mixtures of Sulfide, Sulfite, Sulfate Owens Dry Lake, California.” Chemical Geology 229 and Thiosulfate.” Journal of Chromatography A, 1085 (2006)Fig 1. Sulfur 257 –concentrations 272 at test sites in the Owens Dry Lakebed. (2005) 47-53 6From ctd ibidRyu et al. Alternative Sources of Photographic Fixer 3 sulfite, sodium thiosulfate, and sodium chloride likely. thiosulfate, even higher quantities of sodium sulfite would However, especially with regards to the former two, they be needed for photochemical applications. may not be present in quantities sufficient for Sodium chloride could offer another, more stable photographic processes. source for a fixing agent. However the fixing action may There is little information on thiosulfate levels in be so weak as to be ineffectual. Impurities (such as trona natural water sources. In a comprehensive review of the and other sodas) in the brine of the lake may also further literature, Xu et al (1998) note, “Attempts to measure inhibit or interfere with fixation. thiosulfate and polythionates in mineral waters and hot If any of these sources is to be pursued, some method springs have been few.7” The same report goes on to of (a) refinement (filtration, etc); (b) stimulation (such as provide a rather complete review of such studies. Notable boiling); and/or (c) additives (such as sulfites added to is the early work of Clark in the Pyrenees8; Headden who harvested samples with elemental sulfur) will almost measured thiosulfate in Doughty Springs, Colorado9; and certainly be required. Allen and Day at Yellowstone National Park10 and Geyser 11 Springs, California. The more recent work of Xu et al, A NOTE ON ONIONS also measured levels of thiosulfate at 39 thermal springs Another interesting potential source for an alternative in Yellowstone.12 Based on figures given in this last fixer in the Owens Valley, which appeared in this report it seems that levels may be too small to be useful research, is the IOU garden. Both onion and garlic for photochemical purpose. Of the 39 springs and geysers produce an organosulfur compound very similar to measured within the park, Xu et al found the highest sodium thiosulfate: sodium n-propyl thiosulfate (NPTS) concentration of thiosulfate to be at 95 µmol/L (or and sodium 2-propenyl thiosulfate (2PTS), approximately 10.65 mg/L). It is true that this study respectively.13,14 I could not find any experimental data sought to measure levels below the surface of the spring on using either as a photographic fixer, however, a thread so as to exclude the effect of oxidation at the surface.