Color Correction Filters for Night Photography

[lilmsmaggie]

Warning! This is another one of those newbie questions.

I've been dabbling in night photography lately and I think I'm beginning to enjoy it. I've been focusing on Architectural exteriors as subjects.
Anyway, I understand that certain color compensating filters can be used during nighttime exposures, or in low-light settings such as building interiors.

I've managed to collect a fair amount of screw-on type filters, but I've considered moving to a filter set system such as Lee Filters - but I digress.

How do you determine the amount of compensation necessary when shooting lighted buiding exteriors, industrial settings, etc. at night?

[Kevin Caulfield]

Most people probably just accept that they may get some weird colour shifts with long night-time exposures, and for many, that is part of the charm of this type of photography. But if you're determined to get certain colours right, or on the other hand, if you want to get some really outlandish effects, then the simple answer is just to get out there and try some different filters. Oh, and have fun.

[jd callow]

get a colour meter (but you will still have issues) or shot neg film and decide if you want the lights to be white or their normal colour. fluorescent interior lights are a light green and unless you use a '4th' layer fuji film you can't filter them without pink natural lit mid's and highlights. Tungsten is orange and can be filtered with the naturally lit areas going blue. The street lights can be anything from cyan, green or orange and are very tough to manage.

[Q.G.]

The amount of compensation, as far as exposure is concerned, is a matter of using the filter factors the manufacturers provide, fine tuned to different light source types by experimentation.

You can correct fluorescent lights using filters to a fair degree of accuracy using he FL-series of filters. Though 'mixed light' (fluorescent with tungsten and/or daylight) will always be a problem. Even with four layer Fuji film.

There is not just one FL filter, but quite a few FL-filters though, each tuned to a different type of FL-light. Lee has a good selection.

High pressure mercury lights (also used in street lights) are difficult too, but the FL-filters may work.

One type of light that is impossible to correct is the one that only puts out a very small part of the spectrum. Sodium street lights, for instance.

[2F/2F]

If you are not the one controlling the light for the shots (i.e. shooting interiors as they actually are with their existing real-world lights; not set up with your own lights), you will probably never be exact, as mixed lighting is an almost ubiquitous fact of life in shooting architecture as it lies. You can get perfect balance if there is only one color of light illuminating the subject, and you know what that color is (know exactly what lamps are being used, or have a color meter).

Mixed lighting is really a big problem more than is getting the perfect balance for any one type of illumination. Ideally, you go in and replace all lamps with your own lamps, and/or filter existing lamps. You usually have to change the practicals to lower wattage lamps so they don't blow out, not to mention filtering them if necessary to match other lamps in the composition. In mixed lighting, you choose one type of lamp to which you will correct your film, and filter any differently-colored lamps to match the color of the main lamps.

For shooting architecture that is mostly illuminated by warm light, you may find tungsten-balanced films useful.

To start, I suggest getting the two main color conversion filters, an 80A and an 85B (for major correction), as well as at least one each in the 81 and 82 series (for minor correction), and a 30 or 40 magenta CC filter (for green fluorescent light). I would go for the 81A and the 82B. 81A warms color temp by 200K. 82B cools it by 300K, for using tungsten films with household lamps. If you want to go on from there, I would go for a whole set of CC gels, like the Sinar set.

[polyglot]

There's also long exposure reciprocity failure, which causes colour shifts in some films. Provia seems pretty immune to it though, so if you want exposures of more than a couple of seconds without having to take another factor into account, try some of that. Velvia goes greenish after about 1s and there's data out there that tells you how much of a magenta filter you need to use to fix that as a function of exposure.

Other than that, I think you just have to accept that things at night have pretty crazy colours and let that work to your benefit rather than fix it. Try with both daylight and tungsten balanced film. This is me coming from a "pretty pictures" background, not trying to work as a professional to generate an image of record of a client's building, for which you may need to replace or filter light sources so you don't have mixed lighting.

[Q.G.]

Mixed lighting is really a big problem more than is getting the perfect balance for any one type of illumination. Ideally, you go in and replace all lamps with your own lamps, and/or filter existing lamps. [...]

Indeed.

But having said that, it also bears considering that changing everything so that it matches (apart from being very difficult, if not impossible) will also change how the scene looks, in a way that makes it appear rather unnatural.

So, luckily, there is no need to make everything the same, and the next bit is the way to go:

In mixed lighting, you choose one type of lamp to which you will correct your film, and filter any differently-colored lamps to match the color of the main lamps.

... yet i would change that to say that you choose the main type of light, which you will correct using a filter on the lens, and just let the rest be.

[lilmsmaggie]

To start, I suggest getting the two main color conversion filters, an 80A and an 85B (for major correction), as well as at least one each in the 81 and 82 series (for minor correction), and a 30 or 40 magenta CC filter (for green fluorescent light). I would go for the 81A and the 82B. 81A warms color temp by 200K. 82B cools it by 300K, for using tungsten films with household lamps. If you want to go on from there, I would go for a whole set of CC gels, like the Sinar set.

After reading my original post, I just realized that I left out a piece of important information. Please accept my apologizes.

For this project, I'm using ISO 400 rated B&W films (HP5, Delta 400). I think I may have a 80A filter, and I have a Tiffen CC30 Magenta on its way. I've never used a CC filter like Magenta before. Not really sure what to expect.
I don't have a color meter. In fact, I don't have a hand-held meter period.

I do have a roll of Fujifilm 160, but at present I've confined myself to shooting B&W.

[2F/2F]

No; there is no need to make everything the same...unless that is what you have decided that you want in the picture. As for changing the "look" of the scene, I trust that someone will only change the look of a scene to a look that they desire for their shot, and not make aesthetic decisions based solely on technical criteria. Taking any of these lighting or filtration steps is not something that you would do unless you were trying to change the look of the scene. I was not trying to tell the OP what aesthetic decisions to make ("Every shot must have color-matching light sources!"); only telling the OP some options for matching the colors light, if that is what he/she wants to do. If you want to shoot something as it lies, then just shoot it as it lies, of course. Choose a color temp to call white (via film selection and filtration), and let everything else fall where it falls.

FWIW, the latter is usually what I do. I usually use tungsten-balanced film with an 81A filter for night cityscapes with various types of lighting, such as streetlamps, porchlights, building lights, etc. This is calling 3400K white. (It would be the same thing as if I manually set my digital camera's white balance to 3400K.) I have done other things, of course. I have used blue-tinted tungsten lamps, filtered various lamps to match others, put huge gel filters over windows, etc. The most common gel/filter I use for shooting interiors is ND. I use it in light fixtures, over windows, etc. Rarely do I have a shot that warrants all of this, but if I do, I try to craft it to be just like I want it using various tricks and such.

Of course, now we know that the OP is using black and white film.....................

[jd callow]

Color correcting B/w will not result in much of a benefit. Thoughtful use of an ND grad or split can help if the sidewalks and streets are receiving significantly more light than the buildings.