Silver halide printing is the process used to produce the traditional black and white and colour photographs we’ve known for more than a hundred years.
Constantly refined over the years, silver halide printing is reliable, dependable, affordable and delivers beautiful, long lasting prints. It’s ideal for loose prints, boxes and albums, where the prints are subject to more handling.
This article is about the silver halide printing process itself. You can read more about the many benefits of silver halide here.
Introduction
The silver halide process produces physical photographs by exposing paper coated with light-sensitive silver halide crystals to a projected image. The image typically comes from a film negative, or more often these days from a digital file.
The traditional film-based process
This takes place in a dark room to protect the latent image.
1. Exposure: Light passes through the negative onto light-sensitive paper. In black and white images, areas of the paper that receive more light become darker in the final print, while areas that receive less light appear lighter. It’s more complicated in colour prints but the same principle.
2. Development: The exposed paper is then processed in a series of chemical baths. The first Developer solution reduces the exposed silver halide crystals to metallic silver, forming a latent image on the paper.
3. Stop Bath: After development, the print is rinsed in a Stop bath to halt the development process and prevent overdevelopment.
4. Fixing: The print is then immersed in a Fixer solution that removes the remaining light-sensitive silver halide crystals from the paper, leaving behind only the metallic silver image.
5. Washing and Drying: Finally, the print is thoroughly washed to remove any residual chemicals and then dried.
Digital silver halide printing
In digital silver halide printers (as at Queensberry) the underlying principles of silver halide printing remain the same, but the prints are created from digital image files. As well as digital cameras, these files can come from scanners or computer files — making it easy to add text, for example, as in school and team photos.
Digital input: Instead of projecting light through a negative, digital silver halide printers use laser technology to transfer the image from the digital file to the light-sensitive paper.
Exposure: The digital image is projected onto light-sensitive paper coated with silver halide crystals from a digital laser (LED) light source. Exposure is controlled digitally based on the information in the image file.
Processing: After exposure, the paper goes through chemical processing, just as in traditional silver halide printing. After development to form the latent image the print is fixed to remove unexposed silver halide.
Digital control: One advantage of the digital process is the level of control over exposure. Digital printers can adjust exposure levels dynamically based on the characteristics of the image, leading to precise control over colour balance, contrast, and density.
Output: Once processing is complete, the print is washed and dried to create the final photograph, which will retain the characteristics of traditional silver halide prints, such as rich colours and archival quality.
Recycling: Residual silver is recovered for recycling, and output water filtered.
Alexandria
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