One of the difficulties for many photographers who use film is exposing it correctly at night. Shutters are different in every camera, so you have to do your own testing to get good results. You have to expose the film correctly and make sure that you expose for the shadows and develop for the highlights. This has been the motto of many great photographers for many years. Film can capture great detail in the shadows and highlights, but if you do not control the developing process, the highlights will end up as white patches with no detail. By controlling the developing process you control the highlights. This will give you images with great tonality.
Can you imagine an exposure of 256 seconds? And this is without compensating for reciprocity failure.
Since film cameras will not record everything you do in the field, bring a notebook to document everything you do in the camera. Also, bring a tripod, cable release, flashlight and lots and lots of patience. Patience is probably the most important part in the process of using film. Also, don’t just shoot willy nilly; be selective of what you photograph. Remember that a roll of film is only 24 or 36 exposures; make everyone count as if it was the last photo you were ever going to create. This will make you a very good, or better yet, a great photographer.
Film photography is a lot more than just a push a button and hope for the best. Can you get beautiful images with digital? Of course! Can you use your digital camera and do the same extra-long exposures? Absolutely! But compare digital to film; nothing will beat the thrill of seeing your first print that you carefully composed, developed, tested, and exposed as it slowly appears in a developer tray.
So, with the film that you have in the camera your exposure is 16 seconds but, this is before compensating for reciprocity failure or a different aperture of the lens. I know that using the lens fully open is a good idea but maybe you want to use a smaller aperture, let’s say f/8. The chart is correct for the film with the ASA you have in the camera, but not for an aperture of f/8. For that aperture, keep adjusting. Please notice that now that we found the correct exposure for 200 ASA film, we keep that ASA and change the aperture of the lens only! Since we are cutting the amount of light in half every time we close the aperture of the lens, we double the exposure time to compensate. ALL these combinations will give us exactly the same amount of light in the film; this is called reciprocal exposures.
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Firstly, if you want to try film for night shooting then careful thought has to be put into film choice, most Black and White films suffer what is termed reciprocity failure, this is caused by exposures usually longer than one second, at speeds below this film loses its sensitivity in how it reacts to light, it slows down and compensation needs to be given to the exposure time.
As an example, if I needed to set an exposure of say 40secs at a given aperture, a film such as Kodak Trix 400iso would need the 40secs extended to around 300 secs, now on a cold winters night standing around for that time is not always a practical thing to do.
The other disadvantage is aperture setting, for the majority of my night work I use medium format cameras, 6×6 and 6×9 formats, because of the negative size and its ratio to focal length you will have a narrower depth of field, (areas in and out of focus), wide apertures are not always good to encompass a scene from foreground to infinity, or for zone focusing so it is beneficial to use smaller apertures like f11,16, or even f22 to get that all important depth and clarity into our images.
Using films that have reciprocity failure characteristics forces into into wider apertures to keep the exposure times practical, as another example if the metered exposure was 1.5 mins at f16 with Trix then I would need to expose for 17mins, that’s a long time to be stood about in a dark alleyway at night, (unless you have Rottweiler with you, however, there is a solution, read on.
The solution is called Fuji Acros 100iso, a film that does not suffer from reciprocity failure, at least not up to two minutes, after that you just add plus 0.5 to your exposure, so in the above example of Trix at a metered exposure of 1.
5 mins with Acros would be 90sec, a massive difference.Film has the ability to capture a wider range of tones than a single Digital exposure, you will rarely blow highlights, even in street lamps and the shadows will be open enough to show detail, it has a built-in safe guard called latitude, under or overexpose and you will always be able to bring it back, (that’s providing your not 10 stops over or under) 3 stops, either way, will still yield an editable and printable image.
Another control after exposure is in development, let’s say a normal development time for Fuji Acros in daylight is 10 mins at 20c, to bring down highlight density always under develop by at least 10%, this will have little effect to shadow or mid-tone qualities only the higher regions are slowed down in the development process and keep the densities at usable levels.
Most users of Digital cameras these days use zooms, even fixed lens that does not have a depth-of-field scale on the lens and normally auto focus on something, that’s not a good way of calculating distances, the best way is to use the lens scale that will give the maximum DOF possible for a given lens, in other words, you don’t even have to focus on your subject, set the scale and forget about it, most film cameras prior to auto focus have these scales.
Metering night shots is NOT a nightmare, its relatively simple, you might waste a roll or two on your first outings but believe me after that you will recognize the intensity of light and be able to give a qualified guess erring on more exposure is better than less, by that if you’re unsure and you think it needs 40sec give it another 20sec on top, it will not ruin your shot, (remember the word latitude) always give more exposure than not enough.
Always remember that if the scene has a lot of dark areas in the composition then you’re likely to overexpose and if there is a lot of light areas it will underexpose, you’re in charge and with a little knowledge you can take control of the metering.
So to summaries: 1/Use a film like Fuji Acros 100iso for shorter exposure times with smaller apertures 2/ Remember that film has a wide exposure latitude to under and over exposure, always err on the overexposure.
3/ Use a camera that has a DOF scale on the body.4/Always use a tripod and cable release.5 Use any form of light metering as a guide only, the best meter is your brain and knowledge of bright areas and dark areas within a composition and alter accordingly.
6/ Keep things simple and use only one standard lens, wide lens get to much in and can clutter night compositions.7/Always carry a torch and a small piece of black card, the card is used to cover the lens to stop anything such as car lights ruining a scene, if one is coming into the scene, cover the lens, pause your time when its past remove the card and carry on counting the exposure time.
Most of all be careful at night, Saturdays are the worst in cities, too much booze around, go to areas that you know are safe (ish) never visit alone renowned dodgy areas, always take your mobile, let relatives know where your going, keep warm and enjoy a whole new world of photography.
Get out and have a go Martin
This breakdown in the usual tradeoff between aperture and shutter speed is known as reciprocity failure. Each different film type has a different response at low light levels. Some films are very susceptible to reciprocity failure, and others much less so. Some films that are very light sensitive at normal illumination levels and normal exposure times lose much of their sensitivity at low light levels, becoming effectively “slow” films for long exposures. Conversely some films that are “slow” under normal exposure duration retain their light sensitivity better at low light levels.
A digital camera helps you to create an image with an extended range by creating multiple images using HDR photography, and then stitching them together in Photoshop. This means that you have to take many steps to obtain the same range of tones than you can obtain in one well exposed negative. With the number of apps and editing programs out there, your options are unlimited! I appreciate that. But, even with all these advantages, many people with very expensive cameras are unfamiliar with the fundamentals of photography and will have just “nice” images on their Facebook wall. Film gives you a deeper understanding of the multiple processes that go into making a solid print suitable for framing. These instructions are designed to help you render consistent high quality negatives.
About the Author: Ignacio Alvarez is a photography instructor at City Colleges of Chicago.
The information included here is what I normally do when I expose film at night or indoors with very little light. I do this to capture enough light and end up with very good negatives. Nowadays not many people know that film has a greater capability to capture light than digital sensors. What I mean by that is that the range of tones is greater in film when exposed properly. So, to capture enough light on film and have the range you are looking for, you have to do it well.
Another example: For a given film, if a light meter indicates a required EV of 5 and the photographer sets the aperture to f/11, then ordinarily a 4-second exposure would be required; a reciprocity correction factor of 1.5 would require the exposure to be extended to 6 seconds for the same result. Reciprocity failure generally becomes significant at exposures of longer than about 1 second for film, and above 30 seconds for paper.
Hilton Towers lobby Hotel on Michigan Ave. Kodak Film 25 ASA shot at 12 ASA
At very low light levels, film is less responsive. Light can be considered to be a stream of discrete photons, and a light-sensitive emulsion is composed of discrete light-sensitive grains, usually silver halide crystals. Each grain must absorb a certain number of photons in order for the light-driven reaction to occur and the latent image to form. In particular, if the surface of the silver halide crystal has a cluster of approximately four or more reduced silver atoms, resulting from absorption of a sufficient number of photons (usually a few dozen photons are required), it is rendered developable. At low light levels, i.e. few photons per unit time, photons impinge upon each grain relatively infrequently; if the four photons required arrive over a long enough interval, the partial change due to the first one or two is not stable enough to survive before enough photons arrive to make a permanent latent image center.
Go to a dark (and safe) area of your street, it doesn’t matter what you photograph; your concern right now is on learning before creating. Set your camera in the tripod, screw in the cable release, and set the ASA in the dial as high as it will go. Older cameras can go to 1600 or 3200 ASA; set it there. Now set your lens to the biggest aperture—let’s say f/2.8. Look at your light meter and read the shutter speed. What is it? If you are in a very dark place, your light meter will probably give you a long exposure even with the ASA at 1600. Let’s assume that the correct time that you read in the light meter is 2 seconds. If you had 1600 ASA film in the camera this will be half okay, but you don’t have that. Remember, we are shooting with Ilford HP5 400 at 200 ASA. Copy this sample chart in your notebook so you remember it for next time:
So the camera is set, the film is in, everything is working correctly. You are ready to go and expose film. But, when shooting film at night it actually loses speed and the actual film speed or ASA is not valid. So, you must take that into account and compensate for Reciprocity Failure or ‘reciprocity law’ (what happens to film at night, or indoors with artificial light and very long exposure).
Since they did not want people in the picture (below) and this lobby is busy 24 hours a day, I ended up using a small aperture on a Linhoff medium format camera and shot the picture exposing it for 32 minutes after reciprocity correction.
I strongly recommend Ilford films. I use Ilford HP5 most of the time as it has very little grain (if you expose it correctly). The second film that I recommend is Kodak Tri-X; this is a legendary film. A little too grainy for my taste, but a great film nevertheless.
Reciprocity also breaks down at extremely high levels of illumination with very short exposures. This is a concern for scientific and technical photography, but rarely to general photographers, as exposures significantly shorter than a millisecond are only required for subjects such as explosions and particle physics experiments, or when taking high-speed motion pictures with very high shutter speeds (1/10,000 of a second or faster).
Before you have the film in the camera, make sure everything is in working order: Apertures, shutter speeds and light meter. Since we are trying to expose film correctly, do not set the ASA in the camera to 400, which is what the film is rated. This number will give you okay negatives but not very good negatives. So, set your ASA to 200 and follow the light meter! What I mean by this, is to make sure that you do not over or under expose each shot. Of course, you do not have to do this all the time, only when you want very good negatives! Some students overexposed their negatives on top of the ASA sensitivity compensation and then want to under develop the roll based on something they read on the internet! Wrong! Develop the film normally, at the correct time. You want one stop of over exposure in your negatives, otherwise, if you under-develop, you undo this compensation and will screw up the rest of the images in the roll which were properly exposed.
Finally, here is an additional chart where I use 100 ASA film at a very small aperture of the lens and compensate for reciprocity accordingly. Remember, the longer you expose film the more it loses speed, this is why I compensate to such percentages.
First of all, film does not respond to artificial light the same way as digital camera sensors. I suggest that if you want a type of film that responds to all types of light, you use panchromatic film. What is panchromatic you ask? Panchromatic film is a normal black-and-white film sensitive to light of all visible colors (electromagnetic wavelengths between 400 nm and 700 nm). There are other types of film, for example, orthochromatic film, which is not sensitive to all waves (colors) of light.
For most photographic materials, reciprocity is valid with good accuracy over a range of values of exposure duration, but becomes increasingly inaccurate as we depart from this range. As the light level decreases out of range, the increase in duration, and hence of total exposure, required to produce an equivalent response becomes higher than the formula states. For example, at half the light required for a normal exposure, the duration must be more than doubled for the same result. Multipliers used to correct for this effect are called reciprocity factors.
I wrote this article for my darkroom photography students and for others who want to shoot photos at night using film but have no idea how to do it. I know that few people these days are creating images with film and the ones that are, are either very savvy or are totally lost. Taking pictures with film is very different than using a digital camera. With film, you want to expose properly so you end up with very good negatives to print.
If you’re interested in knowing more about panchromatic film, here is a link with more information: https://en.wikipedia.org/wiki/Panchromatic_film
By Brian: Nice writeup! I’ve just got my hands on a rolleichord 6×6 and I’ve been shooting at night using a reciprocity chart and tri-x (o ordered some t-max 100 though because it has less failure). I’ve been using a gossen Luna pro and metering for iso 200 and sticking around f11 .
.. seems my average exposure is something around 95 seconds to 3:30 seconds under average city lights. I haven’t developed any rolls yet and I started second guessing my methods but from reading your post it seems I should just relax and keep on bracketing and experimenting.
Of course you are not going to have the same aperture and shutter speeds as in this sample, this chart is simply a calculation reference. Start cutting the ASA in half, each time you cut the ASA in half that corresponds to one full stop of exposure, so just double the shutter speed and the exposure time will be correct.
So, what is reciprocity? Why is it necessary to compensate the exposure on film? Before we continue with the chart, let me tell you about the Reciprocity Law or the Schwarzschild Effect.