­The Gallery commissioned artist Katayoun Dowlatshahi to make 25 colour carbon prints for the exhibition Yevonde: Life and Colour (2023). Here she tells us about her journey in making them and the historical developments that are part of the story.

Colour photo of a woman working at a table in front of prints taped up on a wall

Katayoun Dowlatshahi by Clare Freestone, 2022

Travelling by train through East Anglia, during February 2023 on my way to the National Portrait Gallery, I observed a landscape gripped by a deep frost and enveloped by an even deeper fog. I was struck by the translucent veil of white obscuring the bold colours of the landscape, alluding to a beauty below, taunting my senses and hinting at a complexity of colours, textures, and contours. It was in that moment a liminal experience.

I am intrinsically fascinated by the hidden forces in nature that break through into our visible world in curious ways, such as the miraculous display of colours of light in a rainbow. Light is this most dynamic of mysteries; it is a life force and may appear to be colourless, but on the contrary, is full of colour and endowed with extraordinary properties beyond the visible rays. It is the ‘magic’ that engendered fear and wonder in equal measure through the early 19th century when images were captured through the action of light. It is the magic we speak of when working with analogue photography in the darkroom: the invisible made visible. The etymology of the word ‘photography’ is based on the Greek (phōtos), meaning light, and (graphê), meaning drawing, writing, drawing of light, and attributed to Sir John Herschel in 1839.

Black and white print of an older man's head and shoulders; he has white hair

Sir John Herschel by Julia Margaret Cameron, albumen print, 1867, P201
© National Portrait Gallery, London

In the ensuing decades, silver, gold, platinum, iron and chromium chemistries became a family tree of photographic processes, yielding a world of tone, rich in form, texture and curioscuro. Qualities that are as relevant today as they were then and so desirable in creative hands. By the late 19th century though, the race for colour photography was already underway and by the early millennium, a plethora of experimental colour processes, in-camera and in-print had been invented.

Because of my specialism in the historic Carbon printing process, I was commissioned to research historic pigments used in the Vivex process leading to the production of 25 tri-colour carbon prints for the National Portrait Gallery in London, from their newly acquired collection of separation glass plate negatives by Yevonde. My research for this work took me on a journey of discovery.

A label with an image of camera parts and a Madame Yevonde stamp

Yevonde’s label and stamp showing ‘Natural Colour Photograph-Vivex Print’, 1936 reverse of x26404

To appreciate the significance of Yevonde’s early colour Vivex prints, produced by Colour Photographs (British and Foreign) Ltd., in London, in the 1930s and my Carbon prints of her work today, it is useful to understand the lineage and development of the Carbon print process, its evolution to Carbro and adaptation as Vivex colour printing. These are all chromium based processes, wherein the image is rendered in pigment. In Carbon the active salts of potassium, sodium and ammonium Dichromate (bichromate salts) are used to produce light sensitivity, rather than silver salts.

Mungo Ponton discovered the light sensitivity of paper soaked in a solution of potassium bichromate in 1839, but was unable to explain its chemical properties. This discovery was followed by William Henry Fox Talbot’s discovery that gelatine, when coated with potassium bichromate hardened when exposed to light. This crucial discovery by Talbot was the bases for his new patent Photoglyphic Engraving, the predecessor of all photo-mechanical processes. Talbot’s discovery consequently led to the invention of pigment printing by French chemist, Alphonse Poitevin. His gum bichromate printing was popularised by Pictorialist photographers.

The process was improved on, as a transfer system, but it took until 1864 for it to become a practicable printing process with significant improvements made by Sir Joseph Wilson Swan who sold his patent to John Robert Johnson and Ernest Edwards, who, together, formed the Autotype Printing and Publishing Company in London. They dominated the market for over half a century, for the production of monochrome carbon prints and the sale of pigmented colour tissues.

Black and white photo of a man with white hair and a long white beard

Sir Joseph Wilson Swan by Lafayette, 1900s, x13214 © National Portrait Gallery, London

Black and white photo of a man smiling and holding a cigarette in one hand

Douglas Arthur Spencer by Yousuf Karsh, gelatin silver print, 1950, x201316 © Karsh / Camera Press

Tri-colour carbon evolved as a chromatic subtractive printing process as early as 1868 patented by Frenchman Louis Ducos du Huron. He is referred to as the inventor of colour photography. With the introduction of panchromatic gelatine dry plates in 1905, by the Rotary Company and the production of tri-colour pigment tissue papers by the Autotype Company in England, tri-colour printing became more popular and accessible. One of the earliest champions of emerging colour processes was Agnes Warburg, who was an early pioneer of colour photography and a founding member of the Pictorial and Colour Groups of the Royal Photographic Society (V&A Collection).

But it was The Car-bro (Carbon and Bromide) process that revolutionised subtractive colour printing for photographers worldwide. Images on panchromatic glass plate negatives placed in an enlarger were made larger by projection onto light sensitive silver bromide prints. These were subsequently bonded to the Autotype pigment tissues using a plethora of chemistry, not light, to achieve a chemical reaction between the silver and the chromium chemistry, thus hardening the image onto each of the three respective pigment tissues, Cyan, Yellow and Magenta.

Vivex printing was itself an adaptation of the Car-bro technique. The first time that full colour prints became available on a commercial bases due to the standardisation of each stage of the printing process by Colour Photographs (British and Foreign) Ltd. It is in this colour technique that Yevonde found her medium of choice.

Autotype was commissioned by Colour Photographs (British and Foreign) Ltd to create bespoke pigment tissues, to their colour saturation and specifications, for use in the production of Vivex prints. A unique feature of the Vivex process, was the hand manipulation of the wet colour layers using a cellophane film during registration, so that any movement captured from one negative to another could be corrected.

I think Yevonde would have approved of innovation in the procedure; for this retrospective exhibition, her quarter plate glass negatives were digitised. Working with the Adobe Photoshop tool called ‘puppet warp’ I was able to stack all the transparent negatives, to identify mis-registered areas and to correct these.

Screenshot of a black and white image in Photoshop with a pattern of triangles and dots across the image

Screenshot by Katayoun Dowlatshahi, showing use of the Puppet Warp tool in use in Adobe Photoshop on Yevonde’s Orchids, 1939 x220749

Using laser technology, these digital files were exposed onto larger silver halide image setter films using an FM stochastic screen. In one fell swoop, this minimised the plethora of chemicals and simplified the procedure back to the origins of Carbon printing with ultra violet light.

Innovations in the printing process have since led to a safer alternative to the sensitising compound, Dichromate (a known carcinogen) has been replaced with DAS. In Carbon printing, no other chemistry is used during development, only hot water to dissolve the proportion of the image that had not been exposed and hardened by light.

Colour photo of a lens on a white surface against a blue background with coloured dots over the image; a card on the bottom right of the image shows blue, red and yellow

Lens, 1932, tri-colour separation negative x221922

Though the technical process of Vivex production was of great interest to Yevonde as the primary channel through which she expressed her ideas in colour, Yevonde was far more interested in colour as a creative expression and as a means to experiment. She was passionate about the potential for colour in photography and was a leading advocate for its use.

Two prints side by side of a woman in a grey dress with her hands out in front of her resting on a dark surface; the prints have blue, red and yellow lines down the side

Sample tri-colour carbon print of Edith Hart-Davis (Wallace) as Andromeda 1935 (x220010) by Katayoun Dowlatshahi, 2022

So here began my journey learning about colour, within the context of Yevonde’s photographic work. My first test print highlighted the need to be historically accurate in my choice of pigments, especially as black had to be achieved by mixing the other three colours. I had initially used the industry standard yellow, cyan and magenta (generic names given to these colours) calibrated for carbon printing. Simultaneously the digital team at the Gallery were creating digital colour composites of Yevonde’s glass plate negatives and used the same colours but problems of accuracy with digital files emerged in both camps. To be more accurate I had to identify pigments used during the 1930s for the production of the Vivex prints and to share the data with the team.

From initial research I came to understand that pigments used in the printing and photographic industry had changed, due to instability in the pigments, the fugitive nature of the colour or lacking the light properties needed to create an ideal hue. I found a number of references, in the Royal Photographic Society Journals of the 1920 and 1930s to the use of an ‘imperfect blue’. Douglas Arthur Spencer, the Director of Colour Photographs (British and Foreign) Ltd, described the fact that ‘the perfect blue green remains confined to peacocks’ feathers and sunlit icebergs’ and that it did not exist as a pigment.

Cover of The Photographic Journal July to August 1948

The Photographic Journal, July–August 1948, Royal Photographic Society, Bristol, UK

Journal page with a black and white photo of the sensitizing room showing a man working withy various trays and other equipment

In 1929 in a paper presented by L. W. Oliver to the Royal Photographic Society (RPS). Vivex pigments were described as Prussian Blue, the yellow a form of Colloidal Silver, and the red was some form of Murexide. He could not give more specific descriptions. However, by 1931 D. A. Spencer revealed these pigments had been replaced through a desire for greater permanency. Any new pigments used for Vivex printing after 1931, were kept under the radar as commercially sensitive by the company. Prussian blue (ferric ferrocyanide) was in fact used as early as 1868 by Louis Ducos du Huron in his tri-colour carbon process and commonly used in the print industry.

In an interesting RPS article by H. Mills Cartwright published in 1936, 'Photo Engraving in 1935', reference is made to a new class of Iron Blues that had been discovered in 1928 and were being tested - the most significant advance in artist pigments since the discovery of synthetic Ultramarine Blue in 1826. The ‘true pigment’ discovered in 1928 was called Phthalocyanine Blue and was made available in 1935 under the trade name ‘Monastral Blue’. D. A. Spencer demonstrated its use in Vivex prints at another RPS meeting that year.

In the company archives of the Autotype Company at the National Science and Media Museum in Bradford, I was able to evidence the use of Chrome Yellow up to the early 1905 for the preparation of tri-colour pigment tissues. As Chrome Yellow was unstable it was replaced by Cadmium Yellow. However Cadmium Yellow was also toxic and was eventually replaced by Arylide yellow, also known as Hansa yellow, which became commercially available from 1925, though there is no evidence that this pigment was used for Vivex prints.

Traditional Alizarin, Madder Rose and Carmine reds are all classed as Madder Lakes and used extensively in the printing industry in the 18th and 19th century but were fugitive to light. Synthetic Alizarin was the first natural dye to be synthetically produced in 1868, with good light fastness but was slow to be adopted commercially.

At a pivotal moment during my research at the archives of the National Science and Media Museum in Bradford I discovered a set of prints by Colour Photographs Ltd demonstrating the individual colours used in a Vivex print, and as they would appear when superimposed to make up a full colour image, using the Crown Jewels as the subject matter.

Assessing each colour against hand produced pigment samples by Colourmen Kremer in Germany, I was able to make visual comparisons with the Vivex print to find the closest equivalent colour match, with the best light fastness.

Four open jars of paint seen from above, one yellow, two red and one blue; in front of them is a piece of paint with samples of the paint

A range of water dispersed pigments that were tested for the production of tri-colour carbon prints by Katayoun Dowlatshahi, 2022

Alizarin Crimson Dark (PR83) was the closest match for the Vivex red. Imitation Indian Yellow (PY150) was selected for the yellow and for the elusive blue/green colour a mixture of Phthalocyanine Blue (PB15 +) Phthalocyanine Green (PG7). Colour Photographs Ltd were one of the first commercial enterprises to use this newly discovered blue/green pigment for their Vivex prints.

Prints hanging up to dry, slighlty curled at the bottom

The second transfer of the tri-colour carbon prints hanging to dry by Katayoun Dowlatshahi, 2023

All three colours were calibrated to achieve the best outcome from maximum density to the highlights. A colour correction curve was applied to each digital file, from which I was able to output all necessary black & white silver halide negatives to print from. At last I had lift off, and my initial tests proved beyond any doubt that I was on the right path to achieve the warmth and creative distinctiveness of Yevonde’s vision.

By Dr Katayoun Dowlatshahi

A visitor looking at framed colour prints hanging on a yellow wall below the quote: If we are going to have colour photography for heaven's sake let's have a riot of colour

Yevonde: Life and Colour (2023) installation view showing several colour carbon prints made by Katayoun Dowlatshahi.

Watch the film below, in which Dr Katayoun Dowlatshahi makes a colour carbon print of photographer Yevonde's 1937 self-portrait. This film shows Katayoun talking us through the techniques and processes used, and also includes interviews with Curator Clare Freestone and Digitisation Officer Ines Alves.



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27 January 2024, 20:10

Fantastic! Thank you so much for sharing this information with us.

Martin Castle

26 January 2024, 22:58

Fascinating how much research was necessary to achieve what was a set of beautiful images in the exhibition.

Shahpary Pulido

26 January 2024, 20:19

What beautiful work! Extremely impressive bringing the past back to life in colour.