Cyanotype failed? 10 causes and practical solutions
A cyanotype can come out of the sink pale, spotty, blurry or almost completely blue. This is usually not due to one “error”, but to a combination of lighting, coating, contact, paper and coils. With this practical diagnosis you can quickly find the cause and improve the result in a controlled manner.
Start with one controlled test
Don't immediately change several things at once. First make small test strips from the same paper, use the same coating and expose each strip a little longer. Note the time of day, weather or type of UV lamp, exposure time and paper. This way you can see which variable really makes a difference.
1. The print is pale or has little contrast
A pale print is often caused by too little UV light, too short an exposure, old or incorrectly stored solution, or paper that does not absorb the emulsion well. Extend the exposure step by step and check whether the coated parts become noticeably darker during the exposure. Use freshly mixed working solution and let the paper dry completely in the dark.
Do you work with sunlight? Then the same time may be far too short on a cloudy winter day, while it is more than sufficient in the summer. Also read our guide to exposure time for cyanotype .
2. The print is too dark or details disappear
With overexposure, light details become obscured and the image becomes flat. Shorten the time or use a negative with more density. When working with objects, check that thin and semi-transparent materials do not transmit too much UV. Create an exposure series, for example with five increasing times, so you don't have to guess.
3. The coating is spotty or streaked
Streaks are often caused by too much solution, a hard brush, repeated brushing over semi-dry emulsion or unevenly absorbent paper. Using a soft foam brush or coating rod, spread a small amount evenly and stop once the surface is covered. Work on clean, flat material and allow to dry horizontally.
4. The image is partially washed away
If the image almost disappears during rinsing, the exposure was usually too short or the coating did not adhere sufficiently. Some types of paper contain a lot of internal or surface sizing and absorb the solution poorly. Test a suitable, uncoated and acid-free paper for cyanotype . Rinse with gently running water instead of with a hard jet.
5. Yellow or greenish spots remain visible
Yellow residue usually means that not all of the unused chemicals have been rinsed out. Rinse longer with multiple water changes until the water remains clear. Then let the print dry flat. Use clean containers and avoid contamination by residues of detergent, bleach or other photographic chemicals.
6. The blue becomes weaker after drying
Cyanotype reacts sensitively to alkaline conditions. Strongly alkaline paper, certain detergents and a high pH of the rinse water can damage the blue. Do not use bleach and avoid cleaning products. A freshly rinsed print may appear even lighter; the color generally deepens during natural oxidation in air.
7. Contours are blurry
Blurry edges occur when there is space between the negative or object and the coated surface. Use a glass or plexiglass plate and clamp the whole evenly. With a digital negative print, the printed side must be as close as possible to the cyanotype paper. Also pay attention to movement due to wind during outdoor lighting.
8. Drops, fingerprints or strange spots
Wear clean gloves, do not touch the coated surface and check that brushes, measuring cups and work surface are completely clean and dry. Water droplets before exposure locally dilute the emulsion; Grease from fingers actually prevents even absorption.
9. Results vary from sheet to sheet
Accurately measure both stock solutions and mix equal amounts just before use. Always use the same paper, the same amount of emulsion and the same drying time for a test. Store solutions tightly closed, clearly labeled and protected from heat and direct light. Our cyanotype kits and loose chemistry make it easier to work with fixed ratios.
10. Cyanotype on textiles remains light or uneven
Pre-wash cotton, linen or silk without fabric softener. Many new fabrics contain finishes that reduce absorption. Allow the fabric to dry completely, testing a small area first and taking into account the greater fluid consumption of textiles. For a complete procedure, read our guide to cyanotype on textile .
Practical problem solving in three steps
- Check the materials: fresh solution, suitable paper or pre-washed textiles and clean tools.
- Make an exposure test: keep all variables the same and only change the time.
- After complete rinsing and drying, assess: compare contrast, detail and evenness and note the best combination.
Frequently asked questions
Why doesn't my cyanotype turn blue?
First check whether both solutions have been mixed in the correct ratio, whether the coating has received UV light and whether the solution is still fresh. Without sufficient UV exposure, a stable blue image will not be created.
How do I know if a cyanotype has been exposed long enough?
The exposed coating usually turns dark bronze or gray-green during exposure. The precise time depends on UV intensity, paper and negative; a test strip is more reliable than one fixed time.
Can I re-expose a failed cyanotype?
After rinsing, the used coating has been removed or converted and you cannot easily re-expose the same print. Use the result as a test and make a new coating with the adjusted time.
With a fixed method and short test series, cyanotype becomes much more predictable. View all cyanotype supplies or start with a complete package if you want to coordinate all parts.