At the most fundamental level, creating a photograph requires light, a light-sensitive material to capture the image, and a surface (such as paper, glass, or metal) to develop it on.
- Light: This is undoubtedly the most fundamental component of photography. Light is the element that brings life to an image.
- Light-sensitive material: Let's call this the soul of the photograph. It's the medium that traps the light. This material could be the emulsion used to coat camera film or the digital sensors of today.
- Surface: Whether paper or materials such as glass or metal, this serves as the physical form on which the image takes shape. It’s where the captured light becomes an image, creating a lasting impression.
From these core ingredients, the art of photography has developed a rich mixture of techniques and styles. In the early days, photographic pioneers crafted mesmerising images using methods like the Daguerreotype, a silvered copper plate process that fascinated the world in 1839, and into the 20th century colour processes like Vivex—a technique that used multiple colour separation negatives—became hugely popular.
This captivating black and white stereoscopic daguerreotype from our collection transports us to a time when photography was as much about chemistry as it was about art. The stereoscopic image gives an illusion of depth by presenting two flat images taken at slightly different angles, mirroring the way our brain typically fuses these separate perspectives from each eye into a cohesive three-dimensional image.
These are not merely props; they are essential to the Daguerreotype process. A copper plate, coated with silver, undergoes exposure to iodine vapor, creating a light-sensitive surface. The captured image is then developed using mercury vapor and fixed with salt water or a solution of sodium thiosulfate.
This image is not just a snapshot of a moment; it captures a time when science met art, when photographers were chemists, carefully concocting visual masterpieces.
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Vivex was a modification of the Trichrome Carbro process in which sheets of cellophane were used as temporary supports for the pigment images. Any minor problems with the image could be corrected manually by stretching or squeezing the cellophane to ensure perfect superimposition.
Chemical romance
Before pixels, there was chemistry. Early photography was like a magician's potion, mixing silver salts, mysterious emulsions and light in a darkroom dance. For a vintage selfie, you'd need patience and precision to make a photo that wasn’t just snapped but crafted.
The wet-plate potion
Within a leather case dating back to 1854, lie the essential materials of wet plate photography.
Science Museum Group Collection
Ingredients:
1. citric acid
2. carbonate of soda
3. iron III solution
4. crystal varnish
5. unidentified chemical
6. hypo bottle (empty)
7. acetic acid
8. iodised collodion solution
9. collodion solution (residue)
10. pyrogallic solution
11. nitrate of silver solution
12. chloride of gold
Science Museum Group Collection
These are not mere chemicals; they're the vital ingredients of a form that once bridged science and art, a tangible testament to photography's chemical origins.
Daily Herald Archive/Science Museum Group © Mirrorpix
By the 20th century, darkrooms like the Daily Herald's wouldn't have used wet plate processes, but the fast turnaround this mobile darkroom allowed echoes those earlier setups—wet plate photographs had to be processed very quickly, on the move, giving rise to the portable dark room.
Experiments and discoveries
The evolution of photography has been marked by audacious experimentation and awe-inspiring breakthroughs. Innovators like William Henry Fox Talbot and George Eastman took daring steps to introduce new techniques like the calotype and roll film respectively. Today's photographers benefit from a lineage of experimentation that turned a novel science into a global passion.
Recipe lab: Cooking up a calotype with Talbot's special sauce
In Talbot's calotype kitchen, we begin by selecting the finest smooth writing paper, akin to choosing flour for baking, without the distraction of watermarks.
This 'culinary canvas' is then sliced and brushed with a solution of nitrate of silver, before being dried like slow-roasting meat by the distant warmth of a fire.
What follows is a seasoned bath of iodide of potassium, a quick rinse, and another careful drying by the fire. As the sun sets, a twilight infusion takes place, with the paper coated in a pale yellow layer of iodide of silver, then stored away like a preserved sauce.
When the time for capturing an image draws near, a special mixture of two unique sauces, A (nitrate of silver, acetic acid) and B (gallic acid), is applied with a soft brush on the marked side of the paper, akin to garnishing a dish.
This coated sheet is then dipped in water and dried by a fire, much like searing a steak. Now fit for use, the highly sensitive calotype paper captures images and reveals them through another wash and gentle warming, letting the imagery emerge as flavours in a well-seasoned dish.
Finally, the 'flavour' is fixed by washing and drying in a solution of bromide of potassium, preserving the image's unique characteristics, much like sealing in the taste of a culinary masterpiece.
Science Museum Group Collection
Ingredient in focus: Potassium Bromide
Science Museum Group Collection
Potassium Bromide, abbreviated to "POT. BROMIDE" on this nearly faded bottle from the 19th century, was a component in the calotype photographic process. Acting as a bit of photographic seasoning, this compound played an essential role in the chemistry of image-making.
If this old bottle could talk, what could it tell us about images taken over a hundred years ago?
Among the milestones in photography's evolution are both innovations and significant refinements that have shaped our visual culture. For example, the development of tintypes, a process that has made photography widely accessible, helped to democratise visual expression. The creation of Polaroid instant film introduced the joy of immediate image viewing, revolutionising personal photography.
Science Museum Group Collection
And the emergence of digital sensors has reshaped photography once again. For example, in 1968 Peter Noble built a sensor that could convert light into digital information—making it possible to create digital images from life. It's safe to say that digital sensor technology bridged the gap between traditional photographic methods and the unbridled possibilities of digital creativity, marking a significant moment in photography's continual evolution.
Read on to discover more about what's happening in photography today, and how our snaps impact the world around us.
