Cyanotype on glass combines photographic chemistry with the unique qualities of glass, but it is a demanding process that requires careful handling and a good understanding of the materials involved. Daniel Zilbersheid describes the preparation, chemistry, exposure, development, and finishing of cyanotypes on glass, including different approaches for controlling the final result. The process is intended for advanced users with experience in photographic chemistry and laboratory-style procedures. It involves hazardous chemicals, specialized equipment, and techniques that require precision and appropriate safety precautions.

Writer and photography / Daniel Zilbersheid

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WARNING: ADVANCED USERS ONLY: This process requires experience with photographic chemistry, safety equipment, appropriate laboratory procedures, and careful handling and disposal of hazardous chemicals. Read the SDS – Safety Data Sheet before use. Follow all recommended safety precautions, and use appropriate protective equipment and work in a ventilated area.

• Aminosilane
• Isopropanol
• Ferric Ammonium Citrate (FAC)
• Citric acid
• Ferric (III) chloride hexahydrate
• Ammonia, 25% w/w aqueous solution
• Triton X-100
• Glutaraldehyde, 25%
• Agarose
• Potassium ferricyanide
• Sodium dihydrogen phosphate monohydrate
• Disodium hydrogen phosphate heptahydrate
• Methylisothiazolinone
• p-Phenylenediamine
• Resorcinol
• Hydrogen peroxide, 3%

Disclaimer

This article is intended for readers with prior experience in alternative printing and in handling chemicals that may pose potential hazards to the user and to the environment. Neither the author nor the site administrators accept any legal or other liability for any harm that may result from failure to observe established safety practices when working with chemicals or equipment, or from the use of restricted substances in jurisdictions where such restrictions apply.

Safety guidelines for each chemical mentioned in this article are provided in the relevant Safety Data Sheet (SDS), links to which are given at the end of the article. As a general rule, personal protective equipment — gloves, safety glasses, and a lab coat — should be worn when handling any chemical substances; appropriate respiratory protection should also be used when working with volatile compounds or substances that generate dust.

Remember: safety rules are written in blood. Do not disregard them.

Cyanotype on Glass

There is a widespread belief that cyanotype is one of the simplest of all alternative photographic processes, and for that reason it is routinely recommended as a first port of call for newcomers to alternative printing. This, I am afraid, is one of the greatest misconceptions in a field that is already full of them. True, some semblance of an image can almost always be obtained — but in most cases the quality of that image is enough to put any beginner off the very idea of alternative printing forever. I would argue that cyanotype is in fact one of the most demanding and capricious processes in the field: riddled with variables that are nearly impossible to control, and based on compounds of genuinely inconsistent composition. Producing an image with it that justifies the effort involved is genuinely difficult. Despite the process being very old and the literature on it filling a respectable library, no one has yet managed to make it fully reproducible and repeatable. And yet, for those willing to overcome all of these difficulties, the process holds real potential for exhibition-quality results. Just don’t expect it to be easy…

The publication of Mike Ware’s Cyanomicon [1] effectively drew a line under decades of cyanotype research. This monumental work covers the full history of the process from John Herschel onward, and presents the author’s own innovations — New Cyanotype and Simple Cyanotype — which represent a significant advance over the oldest alternative printing method. The process is versatile enough to be applied to a wide range of supports, from paper and textiles to glass and metal. It would seem almost impossible to add anything new to this field.

Printing cyanotype on glass is not new [2]; it has been practised for quite some time. However, I believe I have managed to contribute my own two cents and take the method to a new level. The underlying principles of cyanotype in my approach remain unchanged. Interestingly, the classical citrate formulation with separate development produced the best results. Mike Ware’s oxalate formulation (New Cyanotype) did not work at all, even though I had successfully tested it on paper. This is most likely due to the reason described in Appendix III §8 of the Cyanomicon [1], which discusses the impossibility of obtaining an image when the iron oxalate complex and ferricyanide are separated in two-bath development. It is too early to write off the New Cyanotype for glass entirely — the human factor is never zero — but I will confine myself here to the method in which I have complete confidence.

One of the reasons many practitioners dislike cyanotype is its insistently blue palette. People go to extraordinary lengths to get rid of it. Yet no matter what variety of coffee you bathe your print in, its cyanotype nature will still stare back at you. There is, however, a toning method that can completely eliminate the blue component of a cyanotype print and transform its color altogether. This method is briefly mentioned in the latest edition of the Cyanomicon with a reference to its source [4], but for some reason it has not gained wide adoption — perhaps because of its complex formulation or concerns about archival stability. My friend Alexander Khokhlov in Moscow first drew my attention to it and proposed a much simpler formula that works well on paper. Building on his work, I developed my own toner variant. On paper it behaves somewhat less predictably (occasionally staining the paper base), but on glass it not only completely transforms the image color, it also raises light sensitivity by an order of magnitude — so much so that not only projection printing but direct in-camera exposure of the sensitized plate in a large-format (or even medium-format) camera becomes feasible. In essence, this toner functions as a kind of amplifier-developer, capable of rendering a barely perceptible trace image fully visible.

Along with sensitivity, contrast also increases. For this reason, the method works best with low-contrast (soft) negatives — which is unusual for alternative printing in general. Iron-based processes such as Pt/Pd, Van Dyke brown, and conventional cyanotype all require high-contrast negatives with a high Dmax, as they are inherently incapable of boosting contrast. This also limits direct projection printing with these processes, since source negatives are typically developed to a lower contrast in order to retain shadow and highlight detail and minimize grain. This is precisely where the present method’s advantage comes to the fore: it not only permits the use of soft negatives, it actually requires them. No dupe negatives needed.

What follows is a step-by-step guide with notes on various practical nuances.

I. Glass Preparation

The glass plate of the desired size must be thoroughly cleaned and degreased by any available means. The most rigorous protocol is that of Bill Winkler [5], though I do not consider it strictly mandatory. His recommended phosphoric acid treatment to remove trace iron contamination is, however, particularly relevant for this process.

What is highly advisable is a coating of aminosilane [CAS: 919-30-2], without which there is a serious risk of the emulsion peeling from the glass during processing. A ready-made 2.5% solution of aminosilane in isopropanol from Bostick & Sullivan can be used, or it can be prepared from scratch. The procedure is as follows [6]:

1. Mix 0.5 mL of aminosilane with 0.4 mL of isopropyl alcohol and 0.1 mL of water. Allow the mixture to stand for 24 hours (but no more than 5 days) for the aminosilane to hydrolyze.
2. Thoroughly clean and degrease the glass plates, then wipe them dry.
3. Dilute the prepared aminopropyltriethoxysilane mixture with 20 mL of isopropyl alcohol and apply it with a brush to the surface of each plate that will receive the emulsion. The surface will turn milky white.
4. Allow the plates to stand for approximately 1 hour. If left for more than 2 hours, the white residue becomes virtually impossible to remove.
5. Rinse the glass under running water, wiping it gently dry without applying pressure. The milky haze washes off completely. What remains is an invisible, very thin but durable organosilicon layer that substantially improves the adhesion of the emulsion to the glass.

II. Preparing the Sensitizer

This method calls for potassium ferricyanide to be kept as a separate developer solution rather than incorporated into the coating. The main argument against this approach is less economical use of this relatively expensive compound. However, from a technical standpoint, combining both components in a single coating solution compromises quality: self-masking during exposure reduces contrast and light sensitivity. Development in a ferricyanide bath after exposure offers significant advantages: increased sensitivity, better solution shelf life, and the elimination of bleeding — the phenomenon in which dye from dense shadow areas migrates into adjacent highlight regions. For these reasons, I chose to follow this path, since quality matters more to me than financial considerations.

The sensitizer can be prepared using either the classical method (if you have Ferric Ammonium Citrate [FAC] of a quality you are confident in), or the alternative formulation — a modified version of Mike Ware’s Simple Cyanotype.

A general note: all cyanotype solutions and coated materials must be protected from any contact with iron. Vessels, tools, and water must all be iron-free.

Prepare the sensitizer under dim tungsten illumination — ideally under a red safelight — using one of the following formulations.

Classical Method

• Ferric Ammonium Citrate (FAC), green — 25 g
• Citric acid, anhydrous — 1 g
• Triton X-100 — 1 drop
• Glutaraldehyde, 25% — 400 μl
• Distilled water — to 100 mL

This method is highly sensitive to pH, which must be held at 4.0 ± 0.1. Check and adjust the pH one day after preparing the solution. To lower the pH, I use a 1 M (192 g/L) citric acid solution; to raise it, a 25–30% ammonia solution. Attempting to omit the acid entirely (without it, pH ≈ 4.7) resulted in no image at all. Acidifying to pH 3.5 produced the same result; moreover, at that pH the emulsion peeled from the glass completely during washing. However, when ammonia was added to bring the pH back to 4.0, the sensitizer worked again.

I should note that all of the above applies specifically to the FAC I used in my experiments. There is no guarantee that the same pH relationships will hold for FAC from a different supplier.

It also emerged that citric acid gives the optimal result in this method. Substituting tartaric acid (and especially oxalic acid) adjusted to pH=4 — only reduced light sensitivity, despite what the literature suggests should be the opposite [11].

Tween-20 is a perfectly acceptable, more accessible substitute for Triton X-100 as a nonionic surfactant, though I prefer Triton for its greater efficacy and stability.

Glutaraldehyde is added both to inhibit mould growth during storage and to provide some degree of hardening of the emulsion layer. If glutaraldehyde of a lower concentration is available — as commonly sold in aquarium supply stores — the quantity used must be adjusted proportionally. Sodium formate, mentioned in the literature [12], should be avoided due to its relatively high reduction potential and its biocidal properties only in near-saturated solutions. Thymol is likewise not recommended, as it significantly weakens the emulsion layer.

The sensitizer, stored in a brown glass bottle in the refrigerator, keeps well.

Ware–Khokhlov Method

This formulation is based on the in situ synthesis of ammonium dicitratoferrate (III), as described in the Cyanomicon (§§ 6.7.5–6.7.6 & 7.4) [1], with the key difference that ferric chloride is used instead of ferric nitrate (following the advice of Alexander Khokhlov [7]), and potassium ferricyanide is again reserved for separate development. The formula is:

• Citric acid, anhydrous — 30 g
• Ferric (III) chloride hexahydrate — 20 g
• Ammonia, 25% w/w aqueous solution (SG = 0.909) — to pH 4
• Triton X-100 — 1 drop
• Glutaraldehyde, 25% — 400 μl
• Distilled water — to 100 mL

If ferric nitrate is used, as Ware suggests, ammonium nitrate crystallizes on the surface of the dried layer, causing very slow drying and a mottled final image.

Preparing this sensitizer is somewhat more labor-intensive than the classical formula, but it yields more consistent results that are independent of the variable composition of FAC and far less sensitive to pH fluctuations. Preparation proceeds as follows:

• • 1. Dissolve 30 g of citric acid in 30 mL of water (gentle warming is acceptable).
    2. Add the ferric chloride hexahydrate and dissolve it completely. Use only the hexahydrate; the anhydrous salt gives inconsistent results.
    3. Place the vessel in an ice-water bath and, with constant stirring, slowly add approximately 45 mL of 25% ammonia solution. The solution will turn green. Work under exhaust ventilation and dim tungsten light. Using weaker ammonia will prevent preparation of the sensitizer at the desired concentration; adjust the amount added at the emulsion mixing stage as needed.
    4. Allow the solution to cool to room temperature, then continue adding ammonia drop by drop until pH 4 is reached. A more acidic environment (pH < 4) is undesirable as it reduces layer strength; pH > 4.5 is undesirable due to poorer shelf life, though unlike the classical method, the solution remains functional even at pH 7.
    5. Add the remaining components and bring the total volume to 100 mL with water.

The prepared sensitizer must also be stored in the dark.

For both methods, water quality is critical. Use only distilled or well-deionized water.

III. Agarose

The foundation of this method is the use of agarose as the coating binder. It is important to emphasize that this must be agarose and not agar, despite the fact that agar has long been used to coat glass for cyanotype printing [2, 3]. Using agar (and especially gelatin) will prevent clear, clean highlights from being obtained during toning.

Agarose is available in many grades, differing in purity, electroendosmosis level (EEO), gel melting point, and gelling point (the sol-to-gel transition temperature). The latter two characteristics are particularly important here, as they determine the working temperature for coating. Although much higher temperatures are required to liquefy agarose (92–95°C) compared to gelatin, due to hysteresis the sol remains liquid and transparent as it cools to 35– 42°C (for low-melting [LM] agarose, these figures are approximately 65°C and 28°C, respectively), allowing it to be handled in much the same way as gelatin.

In practice, almost any agarose grade is suitable provided the temperature guidelines are followed. I prefer LE-Agarose (low EEO) or electrophoresis-grade agarose — the purest grades available, with the least variation in quality between manufacturers [13].

Prepare a standard 1% sol by adding 1 g of agarose to 99 mL of distilled water, allowing it to soak for 30–60 minutes, then heating to a boil with constant stirring (a magnetic hotplate stirrer is ideal for this task). The sol must become completely transparent. Lower the temperature to approximately 20°C above the gelling point — for standard agarose, around 60°C; for LM-agarose — 45–50°C.

Divide the prepared sol into two equal parts. One will serve as the subbing layer; nothing further should be added to it, as any additive (surfactant, hardener, biocide) may unpredictably affect adhesion and cause layer peeling during washing. The sensitizer will be added to the second part later, but only after the subbing layer is completely dry. For now, allow the second portion to set in the same vessel in which it will later be reheated.

IV. Coating the Subbing Layer

Place the prepared glass (see Section I) on a levelled, preheated surface with the aminosilane-treated side facing up. The glass surface temperature should be slightly above the gelling point of your agarose (a non-contact infrared thermometer is convenient for monitoring this). Too cold, and the gel will set before it can spread evenly across the plate; too hot, and it will thicken rapidly due to excessive evaporation.

An ideal device for maintaining a stable temperature is a Shabbat warming plate (plata) — a low-wattage electric hotplate used in observant Jewish households to keep food warm throughout the Sabbath without activating new electrical appliances. It is widely available in Israel and Jewish communities worldwide, and is valued for its even, consistent heat. Place a slab of stone or thick glass on top of the hotplate, as its surface can warp slightly and unpredictably during extended heating.

Pour the hot agarose sol (first portion, at 20°C above its gelling point) carefully onto the treated surface of the preheated glass and allow it to spread from the center outward, helping it along with a plastic comb. Surface tension will prevent the sol from running over the edges. Use 0.1 mL/cm2 of sol — for an 8×10″ plate, approximately 50 mL. Less will produce a fragile, weak coating; more will result in staining of highlights during toning.

Once the sol has spread evenly across the entire surface, switch off the heat. Drying takes approximately one day or more depending on ambient conditions. The result should be a virtually transparent plate (or very slightly matte on the coated side). Do not mix up the sides of the glass.

If streaks, blotches, or other artifacts are visible on the dried surface, wash the layer off and start again rather than waste further effort — all such defects will appear in the final image in their full glory.

V. Preparing and Coating the Sensitized Emulsion

Reheat the second portion of agarose gel in a boiling-water bath until it is completely transparent. Allow it to cool again to 20°C above its gelling point, then add the sensitizer at 5% by volume of the sol. The volume of sol should be the same as for the subbing layer — 0.1 mL/cm2 — which gives approximately 0.2 mg of iron per cm2 of coated surface.

This is now a light-sensitive emulsion, so all subsequent operations must be carried out under non-actinic illumination. I prefer low-pressure sodium lamps for this purpose, as their near-monochromatic yellow emission is entirely non-actinic for iron-based processes.

Place the glass with the dry subbing layer face up on the heated, level surface, and apply the sensitized emulsion in exactly the same manner as the subbing layer. Wait for it to dry completely — this time in total darkness. The light-sensitive material is now ready.

VI. Exposure

Place the glass plate emulsion-side down on the baseboard of the enlarger. Cover the baseboard with a non-reflective black material — I use self-adhesive black velvet film — to eliminate internal reflections within the glass. Exposure takes place through the glass, which will become the viewing face of the finished photograph.

A defining characteristic of this method is its remarkable light sensitivity, which makes projection printing fully practical. In my enlarger I used a single 10-watt LED (395 nm), powered by a USB phone charger, as a point light source to print onto 40×50 cm glass plates from 6×7 cm negatives. To obtain a print with normal density for reflected-light viewing, an exposure of 30 minutes was required at a measured irradiance of 10 μW/cm2 beneath the clearest areas of the negative. This gives an estimated system sensitivity (i.e., the exposure required for maximum image density) of H = 300 μW・min/cm2, or 180 J/m2 — more than 33 times less exposure than conventional cyanotype, for which this figure is 6,000 J/m2 [1, App. III.2]. This sensitivity is achieved by excluding ferricyanide from the emulsion, with amplification provided by subsequent toning.

VII. Development

The developer is a 0.1M solution of potassium ferricyanide. For convenience, I prepare a 1M stock solution that is then diluted 1:10 in water before use. The stock is prepared by dissolving 33 g of potassium ferricyanide in distilled water to a total volume of 100 mL.

For an 8×10″ plate, 5 mL of stock solution is sufficient, diluted with 45 mL of water and five drops of a non-ionic surfactant (Triton X-100 or Tween-20, pre-diluted 1:100 in water). Do not add any acid to the developer, as any acid may cause the emulsion to peel from the glass.

Remove the glass from under the enlarger, turn it emulsion-side up, and place it in a flat-bottomed tray. Avoid standard ribbed-bottom developing trays, as the developer will pool beneath the plate and far more solution will be needed. In one swift, sweeping motion, pour the developer onto the glass, attempting to cover the entire surface in a single pour. Rock the tray in all directions for a couple of minutes, ensuring even coverage. Development is virtually instantaneous and goes to completion — in the conventional sense, “overdevelopment” is not possible here, though there is no reason to prolong the process unnecessarily. The developer is for single use.

Unlike conventional cyanotype, the developed image should barely be visible — you should be looking at an almost transparent plate with the faintest hint of something bluish. If the image is clearly readable at this stage, the plate has been overexposed. This is not cause for alarm: it is easily corrected during toning.

VIII. Washing and Drying

After development, place the plate in a tray of distilled water. I hold the tray in my hands throughout washing and rock it gently. Do not be overly vigorous, as the layer is extremely delicate at this stage. After one minute, drain the water and replace it with a fresh batch; repeat seven times in total. No acid is added to the wash water, to avoid the risk of emulsion loss. For this same reason, tap water is not suitable — all washing is done in distilled water. The final rinse can take place under ordinary room lighting.

Dry the plate vertically. Do not proceed to the next stage until the emulsion is completely dry.

Even on a fully dried plate, only the faintest trace of an image should be visible.

IX. Toning

Toning is the heart of this process. Unlike the currently popular approach of toning with tannin or tannin-containing natural substances such as tea, coffee, or oak bark, this method employs what is known as mordant toning with oxidative dye developers. This is not a new concept — it has long been used in commercial fur dyeing [8]. Its suitability for toning cyanotype prints was noted by Eder as early as the 1930s [9], and Mike Ware naturally gave it proper treatment in the Cyanomicon [1, §8.5] with a reference to Heron [4].

This approach has the remarkable advantage of not merely shifting the image color, but actively amplifying the image — bringing a practically invisible print to full visibility. Many familiar photographic developing agents serve as oxidative dye precursors in this system, and there is considerable scope for experimentation [10]. Alexander Khokhlov, for instance, recommends catechol (pyrocatechin), which depending on conditions can yield either warmer or cooler tones on paper while simultaneously amplifying the image [7]. Eder, citing Kallay’s patent, mentions p-phenylenediamine and amidol [9]. Heron [4], referenced by Ware, gives a complex formula containing catechol, phenidone, hydroquinone, resorcinol, caffeine, and even honey (at least there are no bat claws or powdered unicorn horn!). Some formulations work better on paper; others produce excessive staining of the paper base — and for this reason the present method uses agarose as its binder rather than agar or gelatin.

Below is the formula I arrived at after testing a fairly large number of compounds and combinations. At present it gives the greatest amplification along with a very beautiful warm brown tone. This does not mean experimentation in this area is finished, but the formula below is a solid starting point.

Phosphate Buffer:

• Sodium dihydrogen phosphate monohydrate — 10 g
• Disodium hydrogen phosphate heptahydrate — 10 g
• Methylisothiazolinone (MIT), 10% solution — 1 mL
• Distilled water to 100 mL

The buffer keeps well in a sealed container when the biocide (MIT) is present. Its function is to maintain the toner pH at approximately 6.5. Without the buffer the toner will still work, though color intensity and durability will be somewhat reduced.

Toner:

• p-Phenylenediamine, free base — 200 mg
• Resorcinol — 200 mg
• Phosphate buffer — 2 mL
• Hydrogen peroxide, 3% — 4.5 mL
• Distilled water to — 100 mL

⚠ Safety note: p-Phenylenediamine (PPD) is a known sensitizer and potential carcinogen. It is also a well-established developing agent in black-and-white film photography. Beyond its health hazards, its oxidation products will tenaciously stain any surface they come into contact with — which is precisely the property exploited in hair dyes and wool colorants. Gloves and a lab coat will protect your hands and clothing.

The hydrogen peroxide is added to the toner immediately before use; even without it the solution has limited working life.

Pour the prepared toner into the tray with the glass plate placed emulsion-side up. For an 8×10″ plate, 50 mL of toner is sufficient — provided the tray is not oversized. The toner is for single use.

The process begins immediately — the image literally rises out of invisibility before your eyes. Toning time should not exceed 5–7 minutes, unless some degree of highlight staining is an intentional artistic choice. Conclude the process with a 10-minute wash in distilled water.

If toning has gone too far, the tone can be substantially pulled back by washing in mildly acidified water, followed by a final plain-water rinse. I prefer dilute phosphoric acid solution for this purpose. Localised reduction and even fine retouching can be carried out with cotton swabs dipped in the same acid solution, applied to the wet layer.

Where additional tone is needed or small coating defects must be disguised, acrylic artist’s paint works well. Burnt Umber (PY42 + PR101 + PBk7) is an excellent visual match for the color produced by this toning method.

Once the emulsion is fully dry, I back the plate with white aerosol acrylic paint, though this may not be the optimal approach. Nevertheless, it creates a firm protective layer that allows the photograph to be viewed in reflected light through the glass side. In this form, the plate is ready for framing. Mounting in a lightbox for transmitted-light display is also possible; in this case, the printing exposure should be somewhat longer, and the backing should be a clear lacquer rather than white paint (which gives uneven coverage by transmitted light).

According to Heron, in private correspondence with Mike Ware [1], the expected lifespan of such a photograph does not exceed 25 years — however, this estimate was made for unprotected paper prints. I would venture to suggest, though experimental verification is needed, that a photograph fully isolated from environmental effects and free from the impurities inherent in any paper support will survive considerably longer.

X. Conclusions

Despite the complexity of its implementation, this method yields stable, repeatable results, largely because the most problematic variable — paper — has been eliminated entirely. For the same reason, prints made by this process may be expected to have substantially better archival stability (with careful handling of the glass) than paper prints. The method itself, with its remarkable light sensitivity approaching that of silver chloride photographic papers, brings all the advantages of projection printing within reach of the alternative process practitioner — a genuinely outstanding achievement for any non-silver technique.

References

Here is the reference list formatted as clean standard HTML, with the URLs hidden behind the reference text:

1. Mike Ware, Cyanomicon. 2020.
2. Cyanotype on Glass: History, Processes & Variations
   
3. Cyanotype Glass Plates
   
4. Heron, R., ‘Blueprint into Blackprint’, Afterimage, 1, 9 (December 1973), pp. 4–7, 12.
5. The Light Farm – Glass Preparation, Part 2
   
6. Zanin K.A., ‘Color Photography by the Method of Interference Heliochromy’, World of Cinema Technology, 2015, No. 4(9), pp. 18–25. [In Russian]
7. Alexander Khokhlov, private correspondence.
8. Aronina Yu.N., Technology of Fur Processing and Dyeing. Moscow: Legprombytizdat, 1986. [In Russian]
9. Eder J.M., Rezepte, Tabellen und Arbeitsvorschriften für Photographie und Reproduktionstechnik, 13th ed. (Russian translation ed. D.S. Sokolov. Gizlegprom, 1933.)
10. ‘New Vat-Dyes Suitable for Student Experiments’, Journal of Chemical Education, Vol. 37, No. 70 (October 1960), pp. 526–529.
11. A. Hnatek, Phot. Korr., 91, 111–115 (1955).
12. J. Kosar, Light Sensitive Systems, Ch. 2. John Wiley and Sons, New York, 1965.
13. Agarose LE vs. Agarose: The Difference
    

SDS (MSDS):

Aminosilane:
https://www.fishersci.com/store/msds?partNumber=AAA1066822&productDescription=3-AMINOPROPL+TRIETHOXYSI+100G&vendorId=VN00024248&countryCode=US&language=en

Isopropanol:
https://www.fishersci.com/store/msds?partNumber=A4594&productDescription=ISOPROPYL+ALCOHOL+4LT&vendorId=VN00033897&countryCode=US&language=en

Ferric Ammonium Citrate (FAC):
https://www.fishersci.com/store/msds?partNumber=I72500&productDescription=FERRIC+AMMON+CITRTE+PURIF+500G&vendorId=VN00033897&countryCode=US&language=en

Citric acid:
https://www.fishersci.com/store/msds?partNumber=A940500&productDescription=CITRIC+ACID+ANHYD+CRT+ACS+500G&vendorId=VN00033897&countryCode=US&language=en

Ferric (III) chloride hexahydrate:
https://www.fishersci.com/store/msds?partNumber=I863&productDescription=FERRIC+CHLORIDE+TECHNICAL+3KG&vendorId=VN00033897&countryCode=US&language=en

Ammonia, 25% w/w aqueous solution:
https://www.fishersci.co.uk/store/msds?partNumber=A/3320&countryCode=GB&language=en

Triton X-100:
https://www.fishersci.com/store/msds?partNumber=AC215680100&countryCode=US&language=en

Glutaraldehyde, 25%:
https://www.fishersci.com/store/msds?partNumber=S25341&productDescription=GLUTARALDEHYDE+SOLUTION+1L&vendorId=VN00115888&countryCode=US&language=en

Agarose:
https://www.fishersci.com/store/msds?partNumber=S25128A&productDescription=AGAROSE+POWDER+5G&vendorId=VN00115888&countryCode=US&language=en

Potassium ferricyanide:
https://www.fishersci.com/store/msds?partNumber=P232500&productDescription=POT%20FERRICYANIDE%20CERT%20ACS%20500G&vendorId=VN00033897&countryCode=US&language=en

Sodium dihydrogen phosphate monohydrate:
https://www.fishersci.com/store/msds?partNumber=AA1159130&productDescription=SOD+DIHYDRN+PHOSPHAT+MONO+250G&vendorId=VN00024248&countryCode=US&language=en

Disodium hydrogen phosphate heptahydrate:
https://www.fishersci.com/store/msds?partNumber=AA1159236&productDescription=SOD+HYDRN+PHOSPHAT+HEPTHY+500G&vendorId=VN00024248&countryCode=US&language=en

Methylisothiazolinone:
https://www.fishersci.com/store/msds?partNumber=AC459970250&countryCode=US&language=en

p-Phenylenediamine:
https://www.fishersci.com/store/msds?partNumber=AC130570025&productDescription=P-PHENYLENEDIAMINE+99+%2525+2.5KG&vendorId=VN00032119&countryCode=US&language=en

Resorcinol:
https://assets.thermofisher.com/DirectWebViewer/private/document.aspx?prd=ALFAAA13080~~PDF~~MTR~~CGV4~~EN~~2025-09-18%2014:41:58~~Resorcinol~~

Hydrogen peroxide, 3%:
https://www.medline.com/media/catalog/Docs/MSDS/MSD_SDSD93901.pdf

Daniel Zilbersheid works as an analytical chemist in the biochemical research laboratory of the Faculty of Medicine at the Hebrew University of Jerusalem. He has been working with photography for over 40 years, and for the past 15 years has focused on the theoretical and practical study of alternative photographic processes. His particular area of interest is adapting alternative printing methods for projection printing with an enlarger. In addition to Cyanotype, he has successfully adapted Carbon printing, Gum Oil, and Oil Printing to this approach. See Daniel’s website and Flickr.