Early Photographic Processes
The decades following photography’s experimental beginnings in the 1820s and the public availability of a practical photographic process from 1839 were characterised by the introduction of a wide range of photographic processes. The following are a few of the most significant.
Announced in Paris in 1839, the daguerreotype was the first publicly available photographic process. The daguerreotype image was created on a silvered metal plate exposed to iodine fumes, forming a light-sensitive surface of silver iodide. Development was achieved by exposing the plate to fumes of heated mercury and then fixing the image in a salt solution. The daguerreotype produced remarkably sharp pictures, but unlike competing processes, each daguerreotype was unique. This proved to be its major drawback, compared with other processes from which unlimited copies could be made.
One of the oldest and longest-surviving photographic processes, the cyanotype, or blueprint, was invented by Sir John Herschel in 1840, using a mixture of ferric ammonium citrate and potassium ferricyanide to produce light-sensitive paper. As a relatively simple process to prepare and manipulate—it required no development or fixing other than washing—it was popular among amateurs throughout the nineteenth century and has also been widely used by engineers and architects for reproducing technical drawings (blueprints).
William Henry Fox Talbot’s calotype process, the first practical negative–positive photographic process, was patented by him in 1841. A sheet of good-quality paper was first treated with light-sensitive silver compounds before exposure in the camera. This produced an image in reverse, known as a negative, which was then developed in gallo-nitrate of silver and fixed. This concept of photography, allowing the production of an unlimited number of prints from a single image, formed the basis of photographic practice until recently, when it began to be challenged by digital imagery. The calotype negative was the subject of many refinements in the 1840s and 1850s, and it was common practice for photographers to apply heated wax in order to increase printing transparency and lessen the visibility of the paper fibres.
Frederick Scott Archer’s wet collodion process, announced in 1851, became the standard photographic process for both amateurs and professionals from the mid-1850s until the early 1880s. The process proved immediately popular, and within a decade had superseded both the daguerreotype and the calotype processes. To prepare the negative for exposure, a sheet of glass was coated with a solution of iodised collodion (a syrupy liquid composed of soluble gun-cotton, ether and alcohol) and then made light-sensitive by immersion in a bath of silver nitrate. Known as a wet process because the glass negative required sensitising, exposing and processing while the chemicals were still damp, it required significant skill to manipulate, but produced a negative of unsurpassed sharpness and a broad tonal range.
The albumen print, announced by the French photographer and publisher Louis-Désiré Blanquart-Évrard in 1850, was the most widespread print medium in use between the mid-1850s and the 1890s. While the printing process was chemically similar to an earlier process called the ‘salted paper process’, the albumen print was generally distinguishable by the glossy sheen imparted by a preliminary sizing of the paper with albumen (egg white) and salt. After the albumen coating had been applied, the paper was made light-sensitive by the addition of silver nitrate and printed in contact with the negative. The fixed print could then be toned to create a wide variety of colours, ranging from purple-black to a rich chocolate brown. Although it continued to be used well into the twentieth century, its popularity declined after the mid-1890s in favour of a variety of manufactured papers.
The fact that all silver-based photographic images tended to fade was a source of concern from the earliest days of photography, and considerable research was carried out in attempts to produce permanent images. Perhaps the most successful of these was the carbon process. First patented by A. L. Poitevin in 1855, the process utilised the fact that gelatin mixed with an alkaline bichromate becomes insoluble when exposed to light. When printing from a negative, those parts of the image representing shadow tones were hardened by exposure to light, while light areas, protected from exposure, remained unhardened and could subsequently be washed away. Carbon and other pigments could be used as colouring agents to obtain an almost unlimited range of tones in the final image. Because the process does not employ compounds derived from silver, the resulting image is less likely to fade and was widely used in book illustration in the 1870s and 1880s.
What’s Happening to Our Food?
Is the way we produce and process food making it less nourishing than in our grandparents’ day?
A We now know a lot about what food does to the body and the importance of a healthy diet. But what if modern intensive farming methods have affected the mineral and vitamin content of what we eat? Donald Davis, at the University of Texas, has found notable declines in nutrients in crops including tomatoes, eggplants and squash. Davis blames agricultural practices that emphasise quantity over quality. High-yielding crops produce more food, more rapidly, but they cannot make or absorb nutrients at the same pace, so the nutrition is diluted. ‘It’s like taking a glass of orange juice and adding water to it. If you do that, the concentration of nutrients that was in the original juice drops,’ he says. But the idea that modern farming produces less nourishing crops remains controversial, since nutrient levels can vary widely according to the variety of plant, the year of harvest and the time of harvest.
B But intensive farming has also led to a huge increase in food supply, which has undoubtedly had a positive effect on our diet and health. ‘Evidence suggests that some nutrients have fallen, particularly trace elements such as copper in vegetables,’ says Paul Finglas, at the Institute of Food Research in Norwich. ‘Foods are now bred for yield, and not necessarily nutritional composition. But I don’t think that is a problem, because we eat a wider range of foods today than we did 10 years ago, let alone 40 years ago.’ Eric Decker, professor of food science at the University of Massachusetts in Amherst, agrees. If nutrients are declining, the losses are insignificant, he says. ‘Over the last century, lifespans have got longer, people are bigger and stronger, and a lot of that has to do with the food supply being better.’ Even Davis agrees that any differences in nutrient levels are relatively small. ‘Despite their declines, fruit and vegetables are still our richest source of many nutrients, and you can make up for it by eating more,’ he says. ‘But we know that many people don’t get the recommended amounts of nutrients such as iron, magnesium and calcium. They aren’t overt deficiencies in the usual sense, but they increase susceptibility to lots of different problems.’
C In addition to changes in its production, food is being transported over ever-increasing distances. Fruit and vegetables in supermarkets might look shiny and fresh, but often they were picked several days earlier. Some nutrients, particularly vitamin C and folic acid, begin to deteriorate as soon as picking happens, but manufacturers can take action to minimise this. ‘Lots of these reactions are driven by enzymes,’ says Carol Wagstaff, from the University of Reading, UK, who points out that chilling is the best way of slowing down such reactions. That said, if you are choosing between organic fruit or vegetables from a distant country and locally grown, non-organic ones, always opt for home-grown, she says. ‘From a nutritional standpoint, go for the shortest possible supply chain rather than the production method.’
Many kinds of mass-produced fruit and vegetables—most famously tomatoes—are harvested unripe before being transported to supermarkets. Wagstaff agrees that this may cause some loss of flavour, compared with a tomato that you have grown at home and left on the plant until it is absolutely ready to eat. ‘But there’s no way you could do that at a commercial level, because of the bruising and other types of damage that would occur if ripe fruits were transported through a typical supply chain,’ she says. In addition, each method of shipping and storing foods has different effects on the compounds they contain. Vitamin C, for example, breaks down in the dark, whereas glucosinolates—found in vegetables like cabbage—are depleted in the light.
D Surprisingly, frozen fruit and vegetables are often nutritionally better than fresh. ‘Frozen peas are much more nutritious than those you buy ready to shell,’ says Catherine Collins, principal dietician at St George’s Hospital in London. What’s more, frozen foods often have fewer additives. ‘Freezing is a preservative,’ she says. Similarly, processing has become a maligned word in the context of food, but there are some cases where it enhances a food’s health benefits. For example, lycopene—a compound tomatoes are rich in, and which has been shown to protect against certain diseases—is much more readily absorbed by humans from tomato paste than from fresh tomatoes. A recent trend is the sale of ‘fresh-cut’ fruit and vegetables—peeled potatoes, ready-chopped carrots and bagged salads. One in five adults in the UK regularly buys fruit and vegetables in this form every week, according to market research firm Mintel. Surely this cutting and peeling speeds up the degradation of nutrients? ‘There is a chance that ready-prepared vegetables may have a lower content of some vitamins,’ says Judy Buttriss, of the British Nutrition Foundation in London. ‘But if their availability means that such vegetables are consumed in greater quantities, then the net effect is beneficial.’
E The bottom line is that although aspects of today’s food production, processing and storage might make what we eat a bit less nutritious, they are also making foods more available—and this is far more important. ‘The most important thing you can do is eat more fruits, vegetables and wholegrains, and cut down on highly refined, processed foods, vegetable oils and added sugars,’ says Davis. He believes this will make a far greater difference to us than worrying about growing methods and transportation.
Rewilding
Ecologist Derek Gow looks at the challenges of ‘rewilding’—restoring areas of land to the wild and reintroducing their original animal species.
In the Netherlands they have developed a creative landscape philosophy called ‘New Nature’, and the most iconic illustration of this is the site called the Oostvaardersplassen, near Amsterdam. Here, throughout 6,000 enclosed hectares, feral Heck bulls excavate amphibian ponds with their hooves and horns, while stags and stallions battle fiercely for possession of herds of females. These creatures present a living vision that many ‘rewilders’ adore. Although this project may present a primeval impression, in reality it is a completely artificial, though courageous, creation, limited by fences, budgets, an adjacent main railway line, surrounding land users and fickle political support. Less than a lifetime ago, the landscape these ‘wild’ herbivores now occupy was the bed of the North Sea.
Despite the contention that surrounds such projects, the Oostvaardersplassen has produced some inspirational results. Spoonbills have returned to breed in ever-increasing numbers, creating a surplus population which has spread back into Britain. Sea eagles have raised their first nestlings in centuries, nourished by the ample supply of deer that the site affords. Projects of this type, which restore key species or re-engineer landscapes to allow natural processes such as seasonal flooding or forest fires to reoccur, have demonstrated that when nature is given free rein, the results which arise can be truly spectacular. Are we, however, prepared to live in landscapes where these processes, even if appropriately modified, become part of our own experience?
While space is without a doubt one of the biggest obstacles facing rewilders, a range of structural, social and cultural issues can also conspire to hinder change. As an example, I have been involved with the restoration of the Eurasian beaver—a large rodent that builds complex structures from wood, stones and mud across rivers—in Britain since the early 1990s. Although they once had a world range which extended from Britain to China and numbered tens of millions, beavers were hunted virtually to extinction by humans as a result of an insatiable demand for their fur, scent glands and meat. They have been widely reintroduced throughout much of their former European range as an awareness of their critical function in the creation of wetland habitats has developed. Beaver-generated landscapes also play a significant part in the retention and purification of water.
There is an abundance of entirely suitable beaver habitat available in Britain, and despite the fact that occasional conflicts will arise between beavers’ engineering activities and human land use, European experience again demonstrates quite ably that these conflicts are manageable. Despite this well-established knowledge, the restoration of beavers in Britain has proven to be a pitifully slow process. Political apathy and indifference have coupled with the total lack of knowledge of opponents who simply want no change to the status quo. The official trials in Scotland and England have focused on the creation of tiny populations which remain extremely fragile.
If a species as benevolent as the beaver presents a significant challenge, then how much more difficult will it be to restore predators? While science and experience may dictate that wolves pose no significant threat to humans, their tentative recolonisation of many western European countries over the course of the last few decades has often evoked a primal response. Farmers’ groups have trapped them in pits in France and burnt them to death; hunters have poisoned them for killing ‘their’ deer; kindergarten teachers have implored forest authorities to remove them from the landscape to ensure that this medieval menace does not lurk in the dark when their tiny children go to school on a winter’s morning. Attitude change, it would seem, is a slow and painful process, one not easily turned round by knowledge.
Any start to rewilding is therefore likely to be humble. Despite a measured approach, it is probable that fishermen and their strident support groups may not welcome the addition of the pelican, a 15 kg water bird, to the large number of predators which they already detest. The scientific community may dislike the pragmatism required on a semi-industrial scale to restore small species to remake the base of essential food chains if newly available habitats emerge. Many farmers, despite the sums they would be paid, will not wish to see their once-drained bogs rehydrated, their dead animals consumed by sea eagles or their pastures revert to scrub.
In the end, it comes down to changing patterns. We have moulded the landscapes of the world as a species to suit our own passing needs, predilections and pleasures. While change is commonly opposed on whatever basis arises, change is nevertheless a constant in life. It is likely that ‘rewilding’ or ‘New Nature’—call it what you will—could become a base movement which affords a fresh opportunity to approach nature conservation in a fashion which will, over time, be all the more rewarding for the surprises it presents.