CFPR featured in channel 4’s Food Unwrapped

Research Fellow, Frank Menger, from the Centre for Print Research explains how he was able to recreate the historical process of autochrome photography for Channel 4’s Food Unwrapped. Here, Frank describes how he was able to bring this process, first invented by the Lumiere brothers in 1890, to life and share it with a national television audience.

The challenge: recreating a historical process

In Spring 2021, I was contacted by a TV production company who were looking to record a photography sequence for the popular channel 4 food-science programme, Food Unwrapped. This particular episode was focused on the production of grated cheese and how potato starch is used as a method for de-clumping the shreds.

Following on from this line of enquiry, the programme delved into the past of the autochrome process – the first commercially viable colour positive photographic process, invented by the Lumiere brothers in 1890- which uses coloured grains of potato starch as colour filters to produce a colour positive image on a glass plate known as a lantern slide. The big question from the producers: could this historical process be recreated and would I be able to carry out the experiment? It was a significant challenge bearing in mind that neither myself nor anyone I know in Europe had managed to successfully carry out the process in the last 50 years or so.

Preparing for the experiment

I had already researched autochromes as part of my role as Research Fellow in the CFPR and knew the pitfalls where the chemical processing is concerned. In the original development of the plates, sulphuric acid and potassium dichromate are used. These two substances, in particular potassium dichromate, are difficult to get hold of and would need to be prepared and used under strict laboratory Health and Safety conditions, as they are extremely dangerous and carcinogenic. However, I suggested using an alternative method to achieve the colour image, which does not use either of the two toxic chemicals, and is available ‘off the peg’ from a specialist photographic supplier.

With autochrome plates no longer commercially produced, we had to order six freshly made plates from a contact of mine in the USA.  Luckily, the courier companies did not decide to take an Easter holiday and all materials arrived; it was time to do some testing. I loaded one glass plate into a darkslide holder in complete darkness and exposed for a nail biting 3 minutes. While I could see an image appear on the plate, it didn’t stay long and peeled off the glass after it had dried. But a failed experiment is a good experiment, as at least one knows what not to do and remedial action can be taken. So back to the textbooks it was for me, and after two more tests, I was still very unsure if we would have an image on the glass to show on the day of filming.

The day of filming: would it work?

An early start to the day involved meeting and greeting the film crew and the programme’s presenter Andi Oliver who would also be the subject of our photography experiment. The sun was shining on us and we decided to take the photo of Andi in front of some very colourful graffiti in our courtyard on Bower Ashton Campus. We got some curious looks from the odd passing student when I disappeared under my dark cloth to focus the wooden 10×8 inch camera. Luckily the exposure took only 1 minute and 45 seconds, just long enough for Andi to hold her pose and not move too much to blur the image.

Back in the darkroom, the processing begun, and as there was not much to see in the dark, the crew had a break while I was sweating, not because of the strenuous work, but with excitement and trepidation, eager to see the outcome of the process.

After an excruciating wait of 20 minutes, I was able to turn the lights on and to my amazement, there was an image of Andi on the plate; it had not slipped of the glass and it was in colour.

But contrary to the original autochrome, this image was in negative form, possibly due to the fact that the required second exposure in the process had not been strong enough. But a picture it was, and on showing this to the producer, we both did a little excited dance before revealing the outcome to Andi in front of a rolling camera.

The final result

The final image on the plate wasn’t perfect but it was a colour image, achieved with a process invented over 100 years ago. Everyone was happy to have been able to recreate this historical process with modern processing materials, but nobody was as elated as me. And I still have one precious unexposed plate left to photograph something with. Now what will that be……

The Food Unwrapped episode featuring Frank and his experiment aired on 3 October 2022. You can watch the episode here on All 4.

Featured image top of page: presenter Andi Oliver at UWE’s Bower Ashton Campus.