The Pencil of Nature: Origins and Theory

• This essay prefaces the 24 images in W.H.F. Talbot’s photographic book “The Pen of Nature,” printed at the Talbotype Establishment on his estate.
• A.D. Coleman described "The Pencil of Nature" as a technical manual, history, credo, and prophecy all in one.

Origins of the Idea

• In October 1833, Talbot was sketching on the shores of Lake Como using Wollaston’s Camera Lucida without success.
• He concluded that using the Camera Lucida required drawing skills, which he lacked.
• Talbot tried using a Camera Obscura to project images onto tracing paper, which was difficult due to instability and the complexity of tracing details.
• The beauty of the Camera Obscura images led him to wonder if these could be fixed permanently on paper.

The Initial Theory

• Talbot's idea was to make light imprint images durably on paper, using the principle that light can cause changes in materials.
• He theorized that varying light and shadows could leave an image on paper, stronger or weaker depending on the light's intensity.
• Talbot made a written note of the idea and experiments before returning to England.
• He planned to experiment with nitrate of silver due to its known light sensitivity.
• He knew nitrate of silver reacted to light, but he was unsure if it was fast enough for his idea to work.
• Talbot considered the original idea more valuable than later research.

Early Experiments

• In January 1834, Talbot returned to England and started experimenting.
• He applied a solution of nitrate of silver to paper, but the effect was slower than expected.
• He tried chloride of silver but had similar results, with the paper slowly turning dark violet in the sun.
• Talbot then washed paper with salt, followed by nitrate of silver, to form chloride of silver within the paper, but the results were not much better.
• He varied the proportions and order of applying salt and nitrate of silver in repeated experiments.
• Uneven application of the brush led to the discovery that certain portions of the paper blackened more rapidly, particularly near the edges of the washed areas.
• Talbot hypothesized that less salt made the paper more sensitive to light.
• He tested this by moistening paper with a weak salt solution before applying nitrate of silver resulting in rapid and uniform blackening of the surface when exposed to sunlight.
• This established that a deficiency of salt produced a greater effect, leading to the creation of a subchloride of silver.
• Abundant salt weakened the action of light on the paper.
• Saltwater baths were later employed to halt further light action on sensitive paper during the fixing process.

Creating Images

• By the spring of 1834, after discovering the subchloride formation process, he obtained images of leaves and lace using sunlight.
• Objects were placed on the sensitized paper, covered with glass, and exposed to sunlight, leaving images on the paper.
• Using the Camera Obscura to capture images of buildings failed, as the details of architecture were feeble and shaded areas were blank.
• Additional sensitivity was needed for the paper to work effectively with the Camera Obscura.

Experiments in Geneva

• In autumn 1834, Talbot repeated experiments in Geneva and tested iodide of silver, inspired by Sir H. Davy.
• Iodide of silver was found to be insensitive to light, unlike Davy's claim.
• This showed the unreliability of chemical literature and the need for experimentation.
• Davy likely observed a subiodide, where iodine was deficient, which is more light-sensitive
• The insensitivity of iodide of silver was useful: chloride pictures could be fixed by converting them to iodide via immersion in potassium iodide.
• This fixation process was initially successful, but later issues arose; pictures faded over time due to a whitening effect from solar rays.
• Iodine fixing was deemed unreliable without precautions because of the risk of image obliteration.

Further Attempts and Discovery

• During the summer of 1835, Talbot made attempts to capture pictures of buildings using the Camera Obscura.
• By using repeated washes of salt and silver and keeping the paper moist, the image exposure time was reduced to ten minutes on a bright day.
• These pictures were small, and the larger pictures were difficult to produce, due to the challenges of keeping the instrument steady and the paper evenly moist for extended periods.
• From 1835 to 1838, lack of time hindered progress, and Talbot considered publishing his incomplete work.
• In 1838, he discovered that colored rings formed around iodine particles on silver leaf and changed color when exposed to light.

Daguerreotype Announcement

• Talbot's progress was interrupted in January 1839 by M. Daguerre's announcement of the Daguerreotype process.
• Daguerre's discovery was celebrated due to its beauty and Arago's enthusiastic promotion.

Prior Work from Wedgwood and Davy

• Talbot found that Wedgwood and Sir H. Davy's research on light from 1802, which he had not been aware of, predated all previously known photographic work.
• Wedgwood and Davy obtained light impressions of objects but failed to fix the images.
• They failed to capture camera obscura images and abandoned the work, which was then forgotten
• Despite the anticipation by Wedgwood and his own contributions, Talbot considered 1839 the birth of photography due to the significant improvements made.

Execution of Specimens

• The design of the copies is almost identical, but the tint varies.
• The variability in tint is due to fluctuations in sunlight intensity and paper quality.
• Sunlight varies even in clear weather, and clouds extend the time for picture exposure
• Differences in paper fabrication and sizing, influenced the color tone of pictures.
• The variety in shades and colors was deemed pleasing.

This text discusses the origins of W.H.F. Talbot's photographic book, "The Pencil of Nature." It covers Talbot's initial experiences with the Camera Lucida and Camera Obscura, which led him to develop his theory of fixing images permanently on paper using light and shadows.