Historical Context
New Cyanotype was developed by Dr. Mike Ware in the 1990s as a modern reformulation of Sir John Herschel's 1842 cyanotype process. While traditional cyanotype remains popular for its simplicity, Ware's version addresses several limitations: faster exposure times, higher maximum density (Dmax), better highlight detail, and more consistent results.
The key innovation is replacing ferric ammonium citrate with ammonium ferric oxalate as the iron sensitiser. This change fundamentally improves the process while maintaining the characteristic Prussian blue colour.
Chemistry
Ware New Cyanotype Sensitiser
Unlike traditional cyanotype, this is a single solution that keeps for years.
| Component | Amount |
|---|---|
| Ammonium ferric oxalate | 30 g |
| Potassium ferricyanide | 10 g |
| Ammonium dichromate (see safety) | 0.1 g |
| Distilled water | to 100 ml |
Preparation
- Dissolve the potassium ferricyanide in 20 ml of distilled water at about 70 °C. Keep it hot.
- Dissolve the ammonium ferric oxalate in 30 ml of distilled water at about 50 °C, then dissolve the ammonium dichromate in it.
- Add the hot ferricyanide solution to the oxalate solution, stir well, and leave in the dark for one to two hours to cool.
- Green crystals of potassium ferric oxalate (about 15 g) separate out. Filter them off and discard them safely. This step is essential: it removes potassium that would otherwise crystallise in the coating.
- Make the filtrate (about 62 ml) up to 100 ml with distilled water, filter again, and store in a brown bottle in the dark.
Work under tungsten light, not daylight or fluorescent light. Ware reports the sensitiser keeps for at least four to five years.
Comparison with Traditional Cyanotype
| Aspect | New Cyanotype | Traditional Cyanotype |
|---|---|---|
| Exposure time | Much faster (about 2–4 minutes under a typical UV source) | 30 minutes or more |
| Dmax | Higher (deeper blues) | Moderate |
| Highlight detail | Better | Can block up |
| Consistency | More predictable | Variable |
| Sensitiser | Oxalate-based | Citrate-based |
| Cost | Slightly higher | Lower |
| Safety | More hazardous: contains a trace of ammonium dichromate (carcinogen) and oxalate | Substantially non-toxic |
Procedure
-
Paper selection: Watercolour papers work well. Arches Platine, Bergger COT 320, or traditional Rives BFK. Sizing affects results—experiment with different papers.
-
Coating: Under subdued tungsten light, apply the sensitiser with a brush or glass rod (about 1.5 ml for a 10×8" sheet by rod). Avoid puddling. The coated paper should stay lemon yellow; reject any sheet that turns green or blue.
-
Drying: Dry in the dark, either at room temperature for about an hour or with warm air (about 40 °C) for about 10 minutes. Expose within a few hours of coating.
-
Exposure: Contact print under UV light: typically about 2–4 minutes under an average UV source. Expose until the highlights look green, the mid-tones blue and the shadows have reversed to a pale grey-blue.
-
Acid bath: Process for a minute or two in very dilute (about 1%) nitric acid; 1-2% citric acid, or 1% hydrochloric or sulphamic acid, are alternatives. Ware replaces the bath after about ten 10×8 in prints (1 litre). Stronger acid gives more contrast.
-
Washing: Wash gently in running water for about 20 minutes, until no yellow stain remains. Avoid alkaline or very hard water.
-
Optional oxidation: A dip of no more than 30 seconds during the wash in 0.3% hydrogen peroxide (50 ml of 6% made up to 1 litre) restores full shadow density at once; Ware notes it makes no difference to the final result, because shadows regain their density as the print dries.
Toning Options
Like traditional cyanotype, New Cyanotype can be toned:
- Tea/tannin: Warm brown tones
- Wine: Purple-brown
- Ammonia bleach/redevelop: Black tones
- Sodium carbonate/redevelop: Split toning effects
The toning chemistry is identical to traditional cyanotype.
Print Characteristics
- Colour: Deep Prussian blue (deeper than traditional)
- Tonal range: Excellent, with better highlight separation
- Shadow density: Higher Dmax than traditional
- Permanence: Good, like traditional cyanotype: keep prints away from alkali (including alkaline buffered mounts), which bleaches Prussian blue. Light-faded prints usually recover in the dark.
Troubleshooting
| Problem | Likely Cause | Solution |
|---|---|---|
| Image too light | Underexposure; exhausted sensitiser | Increase exposure; fresh solution |
| Image too dark | Overexposure | Reduce exposure time |
| Bronzing in shadows | Overexposure | Reduce exposure |
| Uneven colour | Uneven coating; uneven washing | Improve technique |
| Fading | Insufficient oxidation | Let the print dry fully before judging |
Safety
| Chemical | Hazards |
|---|---|
| Ammonium iron(III) oxalate trihydrateWarning | Harmful in contact with skin.; Harmful if swallowed. |
| Potassium ferricyanideWarning | Causes serious eye irritation.; Toxic to aquatic life with long lasting effects. |
| Ammonium dichromateDanger | May intensify fire; oxidiser.; May cause cancer.; May cause genetic defects.; May damage fertility. May damage the unborn child.; Fatal if inhaled.; Harmful in contact with skin.; Toxic if swallowed.; Causes damage to organs through prolonged or repeated exposure.; Causes severe skin burns and eye damage.; May cause allergy or asthma symptoms or breathing difficulties if inhaled.; May cause an allergic skin reaction.; Very toxic to aquatic life with long lasting effects. |
Classifications from the European Chemicals Agency (official EU classification where one exists, otherwise the one agreed by REACH registrants or most often notified). Read the safety data sheet that comes with your chemicals, and dispose of them in line with local regulations.
| Chemical | Hazard | Precautions |
|---|---|---|
| Ammonium ferric oxalate | Harmful if swallowed or in contact with skin (H302, H312) | Gloves; no eating/drinking |
| Potassium ferricyanide | Eye irritant (H319); toxic to aquatic life (H411). Heating or concentrated acid can release hydrogen cyanide | Do not heat or mix with concentrated acid; the dilute processing bath is normal practice |
| Ammonium dichromate | Danger: may cause cancer, genetic defects and harm to fertility (Carc./Muta./Repr. 1B); fatal if inhaled; corrosive; sensitiser; REACH Annex XIV | Avoid the powder (buy as a dilute solution if possible); nitrile gloves, eye protection; dispose of as hazardous waste |
| Nitric acid (1% bath) | Concentrated acid is corrosive and an oxidiser. In the UK, nitric acid above 3% w/w is a regulated explosives precursor, so members of the public need an EPP licence to buy concentrated acid | Buy it ready-diluted; always add acid to water; gloves and eye protection |
New Cyanotype is more hazardous than traditional cyanotype because of the oxalate and, above all, the ammonium dichromate. Ware describes the sensitiser as toxic if swallowed and comparable to kallitype or platinotype sensitisers. It also stains skin, wood and fabric. Dispose of the filtered-off green crystals safely.
When to Choose New vs Traditional
Choose New Cyanotype when:
- Maximum Dmax is important
- Printing negatives with subtle highlights
- Faster exposures are needed
- Consistency is critical
Choose Traditional Cyanotype when:
- Teaching beginners (simpler chemistry, and no dichromate)
- Cost is a factor
- Longer exposures suit your workflow
- Historical authenticity matters
Further Reading
Mike Ware, The New Cyanotype Process (mikeware.co.uk) Ware's own step-by-step instructions for the formula, free on his website. His book Cyanotype (Science Museum, 1999) and e-book Cyanomicon cover both processes in depth.
Christina Z. Anderson, Cyanotype: The Blueprint in Contemporary Practice (Routledge, 2019) Modern comprehensive guide with extensive coverage of both processes.
Anna Atkins' original botanical cyanotypes Historical inspiration for contemporary cyanotype work.
Sources
- The New Cyanotype Process, Mike Ware
- Traditional Cyanotype, Mike Ware
- Publications list, Mike Ware
- Ammonium dichromate substance information, ECHA
- Supplying explosives precursors and poison substances: list of chemicals, Home Office (GOV.UK)