The seaweed seems to float in blue. Pale branches spread across the page, with a handwritten name beneath them. It looks delicate enough to have been drawn, but the shape came from the specimen itself blocking light.
This is Anna Atkins’s Dictyota atomaria, a cyanotype that The Metropolitan Museum of Art dates to about 1853. It belongs to a remarkable approach to making a book: use the plants to help form their own pictures.
Atkins had begun issuing Photographs of British Algae: Cyanotype Impressions in 1843. The V&A describes it as the first photographically illustrated book. Its pictures did not require a camera to look at the seaweed. Light, a prepared surface and the specimen’s position did the work.
The picture begins with a shadow
For a camera photograph, light from a scene passes through a lens to form an image. A photogram takes a shorter route. Put an object against a light-sensitive surface and the object controls where light can reach it.
In a cyanotype, the paper carries a coating made with light-sensitive iron salts. Exposed areas develop the characteristic blue. Material that receives less light stays paler after processing, giving the plant its light shape against a darker field. The V&A’s account of the process describes coated paper, sunlight and washing in water.
That makes the pale specimen more than an outline somebody has chosen to draw. Its shape has helped produce the image directly. A branch interrupts the light; a gap lets the background appear between branches. Thin areas can show differences in tone rather than a perfectly solid white silhouette.
The method also changes the relationship between subject and picture. The specimen has to be arranged at the surface. A lens is not selecting a distant view of it. The result is a record of a particular arrangement, made at close contact.
Why everything becomes blue
The colour belongs to the photographic process. It does not tell us that the seaweed was blue, or preserve the colours somebody would have seen when collecting it.
The New York Public Library’s account of Atkins’s book connects the image to Prussian blue and to John Herschel’s experiments with iron compounds in 1842. The blue is the visible result of the prepared surface responding to light.
That is why a cyanotype can be informative without being a colour photograph. The branches, spaces and edges can remain strikingly clear while natural colour has been replaced by the process’s own palette.
Look again at the pictured Dictyota. The small gaps inside its branching form are as important as the pale areas. They help separate one part from another. The blue is doing two jobs: making the process visible and giving the specimen a field against which its structure can be read.
A direct impression still involved decisions
Atkins wanted a way past the difficulty of drawing small botanical forms accurately. In the introduction transcribed by the Smithsonian’s account of her work, she described obtaining “impressions of the plants themselves”.
Directness did not remove her judgement. Someone still had to choose a specimen, spread its parts and decide how it should sit on a page. The label supplied information that the pale shape could not provide by itself.
Nor does a flattened impression answer every question about a living thing. It cannot show the specimen turning in water or reveal its original three-dimensional form from every side. This is a useful way to read the image’s limits, rather than a reason to dismiss it as a scientific record. It makes some features available with unusual clarity and leaves others outside the frame.
That combination is part of the pleasure of looking at the pages now. They record plants, but they also reveal choices about space, separation and arrangement. The object helped make the image; the page did not organise itself.
A photographic book was still made copy by copy
The word “photographs” can suggest easy duplication. Atkins’s book reveals a more physical kind of publishing.
The NYPL collection history describes specimens arranged on glass to make repeat exposures. Atkins also used the photographic method for title pages and contents lists. She distributed the work privately in parts between 1843 and 1853, sometimes supplying replacement or additional plates. Recipients assembled the parts differently, so surviving copies vary in completeness.
A photographic method had made the specimen into a source for more than one image. It had not made the labour of preparing pages disappear. Each exposure still involved a prepared surface, an arrangement and processing.
That distinction gives the book a different character from a stack of identical reproductions. Its history includes the making and circulation of individual plates, as well as the moment when the complete work is bound and called a book.
The same blue reached the drawing office
The connection with an architectural blueprint is more than a resemblance in colour. The US National Park Service’s conservation guide explains that blueprints and cyanotypes both use light-sensitive iron salts. The process could record botanical specimens and reproduce drawings.
The material also brings a surprise. A brilliant blue image is not automatically an unchanging one. The guide describes fading associated with light and alkaline conditions. Some loss caused by light can recover during dark storage in suitable conditions; that is not a promise that every damaged print can be restored.
The surviving page therefore has two histories. One concerns the specimen Atkins arranged. The other concerns the photographic material that carried its impression through time.
The camera-free method did not capture everything about the seaweed. It did something more specific: it let light turn a carefully placed specimen into a readable, repeatable image. Nearly two centuries later, the pale branches still make that idea easy to see.
Sources
The Met: Dictyota atomaria, about 1853; V&A: photographic processes, cyanotype section; NYPL: Photographs of British Algae collection history; Smithsonian: Anna Atkins and her algae; NPS: caring for blueprints and cyanotypes.