Historical Context
Ziatype was developed by Richard Sullivan in 1995 as a simplified palladium printing process. Named after the Zia Pueblo sun symbol of New Mexico, it combines the relative ease of kallitype with the exceptional permanence of palladium printing.
The process uses lithium palladium chloride instead of the more traditional ammonium salts, which Sullivan found produced more consistent results with better Dmax. The resulting prints rival platinum/palladium in archival quality while being more accessible to practitioners.
Chemistry
Sensitiser Preparation
Solution A — Iron Sensitiser
| Component | Amount |
|---|---|
| Ammonium ferric oxalate | 27 g |
| Distilled water | 100 ml |
Solution B — Palladium Salt
| Component | Amount |
|---|---|
| Lithium palladium chloride | 10 g |
| Distilled water | 100 ml |
Optional Contrast Control
| Component | Amount |
|---|---|
| Potassium chlorate | 5 g |
| Distilled water | 100 ml |
Working Solution
Mix Solutions A and B in varying ratios depending on desired contrast. A typical starting point is 12 drops A : 12 drops B per 4x5" print. Add 1-3 drops of contrast solution for increased contrast.
Procedure
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Paper selection: High-quality 100% cotton papers sized for platinum printing. Arches Platine, Hahnemuhle Platinum Rag, and Bergger COT 320 are popular choices.
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Humidification (optional): Some practitioners lightly humidify paper before coating to improve sensitivity.
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Coating: Under subdued tungsten light, mix sensitiser and apply with brush or glass rod. Work quickly and evenly.
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Drying: Dry in darkness with gentle heat. Sensitised paper can be stored in a dark box for several hours.
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Exposure: Contact print under UV light. Ziatype is a printing-out process—you will see the image appear during exposure. Expose until highlights show detail.
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Clearing: Clear in a sequence of citric acid baths:
- Bath 1: 3% citric acid, 3 minutes
- Bath 2: 3% citric acid, 3 minutes
- Bath 3: 3% citric acid, 3 minutes
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Washing: Final wash for 30-45 minutes.
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Drying: Air dry or blot and dry flat.
Print Characteristics
- Colour: Warm brown to neutral depending on clearing
- Tonal range: Excellent, similar to platinum/palladium
- Dmax: High, with rich shadows
- Permanence: Archival—palladium is extremely stable
- Surface: Matte, image embedded in paper fibres
Contrast Control
Ziatype offers excellent contrast control through:
- Potassium chlorate addition: Increases contrast, adds "snap"
- A:B ratio: More B (palladium) increases contrast
- Clearing bath strength: Stronger acid increases contrast
- Paper choice: Different papers yield different contrast
Comparison with Kallitype
| Aspect | Ziatype | Kallitype |
|---|---|---|
| Final metal | Palladium | Silver |
| Permanence | Excellent | Good (with toning) |
| Cost | Higher (palladium) | Lower |
| Toning needed | No | Recommended |
| Colour | Warm to neutral | Brown (variable with developer) |
Troubleshooting
| Problem | Likely Cause | Solution |
|---|---|---|
| Weak image | Underexposure; exhausted sensitiser | Increase exposure; fresh solution |
| Staining | Insufficient clearing | Extend clearing time; fresh acid baths |
| Low contrast | Not enough chlorate | Add contrast solution |
| Uneven tones | Coating or humidity issues | Improve technique |
| Grainy appearance | Paper unsuitable | Try different paper |
Safety
| Chemical | Hazard | Precautions |
|---|---|---|
| Ammonium ferric oxalate | Toxic if ingested | Gloves; no eating/drinking |
| Lithium palladium chloride | Skin sensitiser with repeated exposure | Gloves essential; avoid dust |
| Potassium chlorate | Oxidiser; fire risk with organics | Store carefully; handle with care |
| Citric acid | Mild irritant | Standard precautions |
Further Reading
Richard Sullivan's Bostick & Sullivan (bfriedman.com) Original source for Ziatype materials and instructions. Sullivan developed the process and continues to refine it.
Dick Arentz, Platinum & Palladium Printing (Focal Press, 2000) While focused on traditional platinum/palladium, contains relevant technical information applicable to ziatype.
Christina Z. Anderson, Gum Printing and Other Amazing Contact Printing Processes Includes coverage of ziatype in the context of iron-based alternative processes.