1830s - early experiments
Having had some success with his photogenic
drawing, sometimes placing an
image directly on his paper and sometimes photographing it with one of
his small wooden cameras in the mid-1830s, Talbot turned his
attention to his other interests.
was not until Daguerre's
photographic process was announced in 1839 that Talbot seriously turned
his efforts again to finding an improved process.
1840s - the Calotype process
discovered his Calotype process in September 1840. He announced
his discovery on 8 February
1841, though at that stage he gave no details of the process. He
patented the process later in 1841.
attraction of the calotype process was that it enabled a latent image on
the paper to be transformed into an actual image after the paper
had been removed from the camera.
calotype process allowed much shorter exposures than for photogenic
drawing, and so made portraits possible. Exposures of around 1 to
3 minutes might be required for a calotype. Talbot's earlier
photogenic drawing process might have required an exposure of an hour.
calotype portraits became possible, as demonstrated by Talbot in October
1840 and by Hill
& Adamson in Edinburgh from 1843 to 1847.
Throughout the 1840s, the
two photographic processes used were daguerreotype and calotype.
the 1850s, most photographers were using the newly-introduced and
patent-free wet collodion process.
John Dillwyn Llewelyn, married to a cousin of Talbot,
continued to use the calotype process for landscape photography,
believing it to produce results that were more sympathetic to the
NOTE ON EARLY PROCESSES
The calotype process, and other early photographic processes involve the
use of acids. and other chemicals. These require a good
understanding and extreme care . I am not in a position to give
advice or guidance.
This site merely gives an overview of the process, without full details,
so that we can get a general understanding of the process, and
appreciate the amount of work that must have been involved for the early
Please note that this web site should NOT be used as a source for
anybody wishing to experiment with or use old photographic processes.
Below are the steps that were taken to create a calotype negative:
Iodise the Paper
a suitable paper.
Many of today's papers
contain hypo or other chemicals that make them unsuitable for the
calotype process. A white paper, with a good wet strength, not
made from wood pulp, and free from watermarks is required.
[Talbot favoured a rag/gelatin paper from Whatman]
2. Brush onto
the paper an 8% solution of silver
nitrate in distilled water. Allow the paper to become matt dry.
3. Immerse the paper in a solution
of potassium iodide 2 to 3 minutes.
[Should this be done under a red
Take care to avoid bubbles.
Then wash the paper for several
hours under running water.
4. Dry the paper, then hang it for
up to two hours in sunlight.
This will help the paper to produce a more contrasty image.
At this stage, the paper
has a coating of silver iodide, which is insoluble and insensitive to
light. This paper should be stored in an acid-free box until ready to
use in the camera.
Sensitise the Paper
When ready to take the
photo, the paper needs to be sensitised as follows, under a red light,
using a Buckle Brush (named after Samuel Buckle) or cotton wool held in
a glass tube, in order to get a good even coating on the paper.
5. Under a red light, coat the
iodised paper with an silver nitrate in distilled water. Other
chemicals are also required at this stage. I believe that these
include glacial acetic acid and gallic acid
Blot the paper to remove
excess liquid, then cut to size for the camera.
Expose the Paper
6. While the sensitised paper is
still wet, expose it in the camera. A two minute exposure at f8
may be required on a sunny day.
7. Brush a solution of silver nitrate (similar to the sensitising solution but stronger)
over the paper, followed by gallic acid.
[Possibly also use acetic acid.]
The image should appear, perhaps in half an hour, or 3 to 4 hours on a
The image is ready when
it shows a good contrast, viewed in red light.
8. Wash the paper, then fix in potassium bromide or hypo to create the calotype negative.
Initially, iodides were used
for fixing. Talbot initially fixed his image using a solution of
Herschell recommended the use of hypo (sodium
hyposulphite - now known as sodium thiosulphate) as a fixing agent but
Talbot was not keen to use this because it tended to bleach his
[Hypo, is still used today for fixing.]
action of hypo was known before the calotype process was discovered. But
hypo was expensive and difficult to use successfully, so it was not
universally used in the 1840s. In fact, in the early days, it may have destroyed more photos than it helped.
Wash the paper, then dry.
The Calotype Paper
The result of the process above is a negative image. This is the calotype.
Talbot, the negative image was an end in itself.
He never retouched his negatives, and it was only with encouragement
from others that he went on to make prints from them
Hill & Adamson and others, it was the final print that was
important. They frequently touched up their negatives by hand,
strengthening lines and adding sky detail.
of the early photographers had no difficulty in making the calotype
negative, but had trouble converting it into a good salt print.
The Paper Print
The calotype created above can then be used to make any number of
prints, using the
Salted Paper print
Alternatively, an Albumen print, or a Cyanotype print could be made from
the calotype negative.
Waxing the Print
the 1850s, it became common practice to wax the calotype negative
on the back, using beeswax, to make it translucent,
before making the salted paper print. This preserved more detail
in the print, and prevented the fibres of the paper from being seen in
If calotype prints are being made today, a sheet of
acetate is recommended between the negative and the paper for the
print, to avoid contamination of the print.
Chemicals for the Calotype Process
is a list of chemicals for the Calotype process, taken from the
Bland & Long published in 1856. Please
click on the list below for further details.
The calotype negative, like
any other negative, had the light and dark tones reversed. It was
not normally considered as an end in itself (except by Talbot).
The calotype negative was
brown when first produced, but began to turn a purplish tone after about 4
Hill & Adamson and others
used the calotype negative to make
These were small brown
images, often unsharp, and now often faded around the edge.
image could be very subtle and had its own
charm - especially when practiced by
The calotype negative was often waxed until it was translucent, in order
to prevent the fibres from the calotype negative being seen in the final
It was possible to make changes to the calotype negative using a pencil,
or to cut up negatives to make a colage, before producing the final
publishing The Pencil of Nature,
the first book in the world to be illustrated with photographs,
came to Scotland with his camera.
took several photographs of Edinburgh, including the Scott Monument, and
Heriot's Hospital. These were used as illustrations in his book,
Sun Pictures of Scotland.
Calotype process was patented in England and Wales, but not in Scotland.
& Adamson, in Edinburgh, achieved
some remarkable results, producing
several thousand calotype images between 1843 and 1847. Adamson
died at the age of 26 in early 1848.
exhibitions of calotypes of Hill & Adamson are planned for 2002,
the bi-centenary of the birth of DO Hill.
photographers who set up calotype businesses in Princes Street, Edinburgh,
in the 1840s included:
who also manufactured lenses
James Ross, who formed several
James Good Tunny, who taught photography to
many of Edinburgh's early photographers.
The book, The Origins of Photography, by Helmut Gernsheim
Richard Morris, who gave a demonstration
of the calotype process in Edinburgh on 11 May 02, as part of the DO
Hill Bi-Centenary celebrations, and who subsequently provided
detailed notes for others wishing to make their own calotype negatives.
Extracts from these notes have been used in describing the calotype