The question begs to be asked: Why use photographic paper negatives, instead of film or a digital sensor? I am sure that by the end of this article you will have a clear answer, but in the meantime let me anticipate a couple of things:
- They are extremely cheap compared to film
- They render magnificently
- They will force you to learn some fundamentals of photography
But all that glitters is not gold, as we will see shortly. So: what are paper negatives?
THE BLACK AND WHITE PAPER NEGATIVE
Using photo paper directly in a camera and developing it produces a negative. Simple. Photo paper immediately leaps to mind for use in the darkroom when printing, but that is not the only use for it. Use as a sensor within a camera is possible, although it follows rules that are sometimes very different from the traditional use of film, and radically different from digital photography. So the process is simple: the camera is loaded with photosensitive paper, the paper is exposed to light in the process of shooting, and then the classic steps of developing, stopping, and fixing are carried out. Each of these steps has its own peculiarities, and with this guide I will try to convey my experience. It is certainly not all-inclusive, but it may be of help to those who want to get started, or who already use photographic paper to obtain negatives but are interested in reading another photographer's opinion. So, let us proceed in order.
WHICH PHOTOGRAPHIC PAPER TO CHOOSE?
There are several photographic paper manufacturers currently in business, and I mention only a few here: Ilford, Adox, Foma, Bergger.
And there are different types of commercial photographic paperwith resin coating or fiber based. What changes between the two is the material. In the RC paper emulsion is protected by a layer of polyether, which imparts impermeability to the paper, allowing it to dry more quickly and hold its shape more easily. In the FB paper emulsion is contained in the fibrous medium that makes up the sheet. This confers a greater
"depth" to the image and richer tones, but it also requires more delicate processing as the paper absorbs chemical compounds during the developing-stop-fixing stages, and requires significantly longer washing and drying times.
The second subdivision of photographic papers concerns contrast: fixed contrast or variable
contrast. To understand what this means, we need to dig briefly into the chemical composition of emulsions in photographic papers. The papers a fixed contrast - "graded" in different gradations - have an emulsion that consistently responds to blue light by returning contrasts to different
gradations based on emulsion composition, historically in 12 levels from 00 to 5. "Graded" papers are now rare, and have largely been replaced by variable contrast papers. The paper at variable contrast is designed to be used in the darkroom in conjunction with filters with which to
modify the ratio of blue/green light reaching the paper. In fact, these papers have three photosensitive layers. Each of the three layers has the same sensitivity to blue light, but each layer has a different sensitivity to green light, from relatively low to relatively high. When the paper is
exposed to blue light only will then result in a high contrast image (all three layers reacted to the maximum of their ability, all being equally highly sensitive); when the exposure is to green light only will result in a low contrast image (e.g., one layer reacted poorly, one averagely, and one very much). Using filters interposed between the source of
light and the paper (such as Ilford filters) it is possible to change the blue/green light ratio, resulting in different contrast images. A magenta filter would block the green and let the blue through à high contrast; a yellow filter would block the blue and let the green light pass à low contrast
Intermediate filter color gradations give intermediate contrast values.
Take the example of Ilford: the company now produces only variable-contrast papers. Foma still produces fixed-contrast papers. Your choice for the darkroom, but what about the field?
Probably the best choice would be to use fixed-contrast papers, so as to have a
fix and reproducible scenario. Personally, I have never used fixed-contrast papers to produce paper negatives, and I preferred to break my head with variable contrast papers. It was what I had available at home (hundreds of my mom's old Ilford MG with some
decades on their shoulders), and with that I continued. So my next experience is with variable contrast paper photography. What advantages does it have? Certainly that you can source from Ilford and be relatively sure about supplies, at a price that is acceptable to date (2023) (~ €0.40 per sheet 4" x 5"), but also that it will leave you with the thrill of the result and will teach you how to study light, how to evaluate what's in front of you, how to make mistakes, and how to figure out what photo to expect, whether to take that photo, and whether the medium you're using (paper) is the most appropriate. It is a life of hardship, but one that can teach much more
than what it takes.
All right, but what is the use of knowing all this? It is useful, indeed, to avoid profound moments of
discouragement using paper to take photos.
WHICH PHOTO PAPER FORMAT TO CHOOSE
Well, this depends on what camera you have at hand, and by the maximum format it can accept. Photo paper can be safely cut and used in a 35 mm camera, and it commonly goes as far as covering formats such as 8×10. In my experience I have used it on large format cameras (4×5 and 5×7). One is an old 5×7 camera from the early 1900s, passed down in the family. It was meant to be used with glass plates, so I had to slightly adapt the original plate holders to accommodate the paper sheets (in my case Ilford MG Deluxe, 10.5 x 14.8 cm). The other camera is an Intrepid 4×5 MK5, with Toyo film holders. Here the paper requires a bit of scissor work to fit the slightly smaller 4×5. But it is such a flexible and inexpensive tool that you can do a little of whatever you like with it.
THE EXPOSURE
And this is where the pains begin. Let's start with a fundamental concept: photographic paper does not have a defined ISO sensitivity as in the case of film. The ISO sensitivity of photographic paper is variable. In the beginning, this concept confused me not a little. How is this possible? Reading on the forums--a place of perdition and a den of discordant information--I was bounced by people who rated paper from ISO 2 to ISO 12, going to extremes at ISO 0.5 and ISO 25. Everything and its opposite. The more
read the further I got from understanding. Why does the emulsion change sensitivity? Why do different people around the world indicate different sensitivities? The answer came to me brutally during my stay in Spain in 2023, when much of the photography I did turned out terribly
overexposed. The answer to those questions was, of course, right under my nose, but it had eluded me since I had never really encountered it. Below is the light sensitivity graph of the Ilford papers.
As you can see there is a pronounced sensitivity to light down to 350 nm, that is, ultraviolet (UV) light. This is the factor that makes the ISO sensitivity of photo paper variable. Visible light radiation is not a constant, either spatially or temporally (think of the color variation of light over the course of a day), and UV radiation is even less constant. Below is an example of how UV radiation varies over the year and day, for example in New York City.
At this link you can see the forecast for the change in UV radiation over Europe over the next three days, while here you can run a simulation of the UV flux for your area. As is evident, not only does UV radiation change throughout the day, but also with the time of year and the latitude you are at. Clouds also block UV rays, but it depends on the thickness of the clouds: it can be as high as 70-80% as low as a few percentage points in the case of lightly dense clouds.
In all these cases the light meter does not help much. Common light meters ignore UV radiation, and thus will not give you any indication of what the correct exposure is.
Summing up: the paper is sensitive to UV radiation, UV radiation changes with latitude, time of day, time of year and sky coverage; therefore, the paper varies its sensitivity according to all these factors.
From what I have observed in my experience, I follow this modus operandi.
1) At my latitude (~12° North), I rate the paper at ISO 3 in winter and on cloudy days. Under these conditions, with no or very low amounts of UV, I rely on the camera's exposure meter with fairly reliable results.
2) On summer days, with photos in full sunlight, I rate the paper at ISO 6-12. The decision is not easy, and depends on how much light there is and on the day itself. A good indication can be to check the UV index forecast to get an idea (see link above).
3) On summer days, and with large amounts of UV rays, the shadows will be brighter, and the scene may have less contrast. This seems counterintuitive, since with bright sunshine summer shadows are sharp and dark. But our eyes do not see the UV rays, which bounce off surfaces and reach the lens even from shadow areas, 'illuminating' them (lo scattering is proportional to approximately the inverse of the fourth power of the wavelength, so it increases inversely to the wavelength: UV will bounce considerably more than red light having less than half the wavelength).
4) In any case, it is essential to gather experience and evaluate the light, and to begin to familiarise yourself with the area in which you are shooting most, and with the environment. For example, a forest in spring will have a predominance of green light, possibly leading to slightly reduced the contrast.
5) Use filters. UV rays can be blocked by using UV filters to be placed in front of the lens or (in large format) even between the lens and paper/film, why not? In any case, using filters can reduce image quality compared to the original lens, and it is not always practical to use them, especially in large format where sometimes the lenses used do not support filters. Filters can also help control contrast. For example, a yellow filter will block blue light, allowing only the green-sensitive elements to react.
THE CONTRAST
We talked a lot about contrast, and for good reason. The dynamic range of photographic paper is definitely limited when compared to film, and even more so when compared to a modern digital sensor. This is mainly due to its low sensitivity to light. Indeed, a minimum number of photons (energy) is required to displace an electron and start the process of forming reaction nuclei on the emulsion crystals. In low-sensitivity emulsions, a greater amount of energy is needed to trigger the reaction, and this energy threshold may not necessarily be reached by the little light radiation reflected from the darker areas. This means that the darker areas of the image will be at risk of being completely black, or at least very dark, contributing to a high degree of contrast. Highlights are also at high risk, as they contain more reflected light, and particularly blue light, which can easily lead to over-reaction that will "burn out" the bright areas during development. A typical photographic paper negative, on a very bright day with a high light difference between shaded and lit areas, will have a dramatic loss of detail. There are, however, several ways of containing contrast and obtaining more detail; I have described them in this page.
If it is still not clear, ideal conditions for using paper negatives are fall, winter or early spring days, or summer days with cloud cover. Shooting indoors presents no particular UV-related problems, but may require very long exposures due to the low sensitivity of the paper.
THE DEVELOPMENT
Once your paper has been exposed, it is time to develop it. All processes can be safely done under red light, since the emulsion of photographic paper is generally orthochromatic (very insensitive to red light). However, the paper should not be kept too close to the red light source, since in the long run even red light is capable of causing a reaction. The development process is the classic process for photographic paper (and film): developing, stopping, fixing, washing, drying. A thorny question now arises: What development time to use? Wherever you read, you will find it written that photographic paper, unlike film, should be developed to completion. That is, until the silver is completely reduced on the emulsion crystals. This is possible because of the physical characteristics of the emulsion in photographic paper, and its relatively low silver content. This principle is sacrosanct, and it applies magnificently to printing. But to paper negatives? The subject is more thorny. We have seen how difficult it can be to calculate the correct exposure, and how easy it is to overexpose. Some of the factors involved are almost impossible to take into exact account in field practice (unless you are so rich and strong that you can carry a spectrophotometer on your shoulders). In my experience, I therefore adopt a number of expedients that help me to obtain a workable negative anyway. They are essentially dilution of the developing fluid and developing by sight. For example, Ilford recommends a dilution of Universal QP of 1+9 (60"), while I adopt 1+19 (80"). This allows me to slow down the developing process, buying me time to make assessments, and on when to possibly remove the negative ahead of time to save what can be saved, or leave it a little longer. The other two undeniable advantages of using a lower concentration are the reduced contrast level and lower aggressiveness of the solution. The negative will begin development more slowly, giving you some relief at the time of immersion and reducing the risk of uneven development.
EN 
IT