Digital Negatives for UV Art
macOS 14.0+A professional macOS application designed for cyanotype and alternative process photographers. Create perfect digital negatives with tone curve adjustments, real-time preview, and precision controls optimized for UV exposure printing.
The scientifically correct way to create digital negatives
Most digital negative software uses simple arithmetic inversion (255 minus pixel value) to convert positives to negatives. This approach is fundamentally flawed for UV-contact printing processes because it compresses shadows while stretching highlights — the opposite of what alternative processes need.
CyanHero uses logarithmic inversion, which maps pixel values so that each photographic exposure stop produces equal tonal spacing in the negative. This is critical because photographic processes respond to light intensity on a logarithmic scale — each stop represents a doubling of light.
output = 255 - input
Uneven stop spacing, faint shadows, excessive highlight contrast
output = 255 × (1 − log(input) / log(255))
Equal stop spacing, full tonal range, process-matched curves
Combined with process-specific preset curves that are designed for the logarithmic base, CyanHero delivers negatives with consistent tonal separation across the full dynamic range of each alternative process.
See the app in action
Real-time preview of your digital negative with tone curve adjustments. Toggle between B&W negative view and blue cyanotype preview to see exactly how your final print will look.
Everything you need for professional alternative process printing
Professional tone curve adjustments with support for Photoshop .acv files. Fine-tune your negatives for perfect exposure.
Built-in curves for Cyanotype, Van Dyke Brown, Platinum/Palladium, Gum Bichromate, and more alternative processes.
Toggle between negative (B&W) preview and cyanotype (blue) preview to see how your final print will look.
Instant preview of all adjustments. See contrast, brightness, and curve changes applied immediately as you work.
Rotate, flip, crop, and scale your images. All the tools you need to prepare your negatives for printing.
Print directly to transparency film or export as PNG, JPEG, or TIFF. Multi-page printing for large format work.
From digital image to classic Prussian blue print
Load your photo into CyanHero
Apply tone curve and adjust contrast
Check blue preview mode
Output to transparency film
UV expose onto cyanotype paper
Wash in water to reveal the print
Professional-grade adjustment tools
Range: 0.5 - 2.5
Adjust tonal separation for optimal printing
Range: -0.5 - 0.5
Fine-tune overall density
Range: 10% - 1000%
Resize for any print format
90° increments left or right
Perfect orientation every time
Horizontal and vertical mirroring
Essential for contact printing
Select and crop to specific area
Undo crop to restore original
Optimized presets for popular UV printing techniques
Classic Prussian blue prints. Preset curve optimized for UV-sensitive iron salts.
Rich brown tones. Curve adjusted for silver-based emulsion response.
Archival noble metal prints. Two preset curves for different paper types.
Multi-layer color printing. Optimized for dichromate sensitivity.
Modern polymer gravure. Curve for precise exposure control.
Load and save your own .acv curve files for any process.
Purchase CyanHero from the App Store for a small fee, which would make me very happy and motivate me to continue developing the app.