I see color filter kits being sold.

  • Red, orange, yellow, green, blue: Descriptions on many websites for black and white photography.

  • Gray: Used like an ND filter?

  • Brown, pink, purple: What are these used for?

color filters


3 Answers 3


Modern digital (electronic) cameras are able to self-adjust “color balance”, (optimize) the overall color of the resulting picture. In other words, pictures taken in daylight with a vast amount of blue sky, tend to come out blueish. Pictures taken indoors under artificial light tend to be off-color based on the type of lighting (fluorescent too greenish) (tungsten too salmon) etc. Again, digital handle these hue errors quite well whereas film cameras require careful selection of film type and the mounting of color modifying optical filters.

Film photography can be greatly enhanced using optical filters. Different films respond to light in different ways. In the early days of black & white photography, films only recorded ultraviolet, violet, and blue light. The resulting images sometime came out quire weird. Cheeks and lips reflecting ruddy light and void of blue, reproduced too dark, even black void of detail. Blue sky recorded too light likely white. Other hue errors were numerous. By the 1940’s black & white film has gained green sensitivity and things improved. By the 1950’s, black and white film gained red sensitivity and things truly got better (not perfect).

Earth’s atmosphere often contains an excess of moisture droplets. Because of their size, they tend to scatter mainly ultraviolet and blue light. In photography, distinct vistas likely mountains and views from high-altitude airplanes reproduce as haze. A UV filter reduces the level of ultraviolet light that reaches the film. The result is a haze cutting effect when a UV is mounted.

We carried a gadget bag filled with filters that corrected for the inaccuracies of film. The yellow filter was most common. It delivered correct monochromatic rendering of colored subjected when using black & white film. In other words, the intensities of how black or gray objects should reproduce was greatly improved by carful selection of colored filters . A red filter was used to artificially enhance the contrast of clouds against a blue sky. The yellow filter did this but with more finesse. A green filter lightens foliage. A deep red gives night for day, movies with nigh scenes was shot with red filter and under-exposed to give an illusion of nighttime. There are many more filter applications with black and white film.

With the introduction of the first practical color film, Kodachrome 1935, filters found other applications. Color films can’t auto white balance. Color films are fabricated for specific types of lighting. In the heyday of color film, it was manufactured for a variety of applications. “D” type for Daylight use. “T” type for applications shooting under tungsten lamps. Since there are several types of tungsten lamps, there was a type “A”. type “B” color films.

Often the camera was loaded with the wrong color film. We would have type “A” tungsten loaded and we worked a daylight scene. The results would be too blue, so we mounted a salmon correction filter. If “D” Daylight film was loaded and the scene was tungsten lit, the results were too ruddy, we mounted a bluish correction filter.
Google photographic filters to learn about their use.

The "pink" actually salmon converts tungsten balanced film allowing it to operate under daylight conditions. The "purple" actually blueish corrects daylight balanced film so that it can operate under tungsten illumination

  • \$\begingroup\$ This otherwise excellent answer would be improved if you explicitly answered the question about pink and purple filters. \$\endgroup\$
    – Eric S
    Feb 6, 2022 at 18:42
  • \$\begingroup\$ The "pink" actually salmon converts tungsten balanced film allowing it to operate under daylight conditions. The "purple" actually blueish corrects daylight balanced film so that it can operate under tungsten illumination. \$\endgroup\$ Feb 6, 2022 at 23:59
  • \$\begingroup\$ Add that to your answer and you’ll get the +1 from me! \$\endgroup\$
    – Eric S
    Feb 7, 2022 at 0:06

What are these used for?

For B&W film photography:

To change the relative brightness of objects that are various colors in the scene.

Color filters allow you to control what shades of grey different colors look like in B&W.

Color filters allow more of the light falling on them that is the same or similar colors as the filter to pass through, while reducing the amount of light that is opposite the color of the filter on the color wheel to pass through. The further away on the color wheel from the color of a filter an object is, the darker it will look than it would otherwise look in an image taken without that filter.

Color filters have been used when making monochrome images for almost as long as photography has existed. The earliest "film" wasn't even film - it was glass or even metal plates coated with a photosensitive emulsion. The earliest chemical formulations discovered to be photosensitive were not very sensitive compared to later emulsions, and what little sensitivity they did have was mainly towards the blue end of the visible spectrum. Only with the advent of panchromatic film could B&W film capture the red end of the visible spectrum as well as the blue end.

Photographers quickly discovered that the use of certain colored filters would make certain things look more "natural" in B&W.

For example, many humans, particularly in the parts of the world where photography began and developed, have red lips. Women in these parts of the world often apply cosmetics to make them even redder. But film that is mostly sensitive on the blue end of the spectrum make red objects look very dark or even black. No one, particularly Western European women in the latter half of the 19th century, wanted their lips to be solid black in photos. By adding a red filter, the photographer allowed more of the red light in the scene to get through to the film, while blocking some of the blue light. Improvements in film sensitivity, both in terms of brightness and spectral distribution, allowed even more use of color filters to change the tonal relationship between various differently colored objects in a scene.

Note that a red photographic filter won't block all non-red light from passing through. It only reduces the amount of other colors that can pass through it. A higher percentage of the red light falling upon it will be allowed to pass through a red filter than any other color of light. A lot of yellow light will also pass through a red filter. A good bit of green light can pass. A lot less blue can pass through a red filter.

Thus, red filters can be used to reduce the brightness of a blue sky while leaving the white clouds almost as bright as they would be without a filter. When we increase exposure slightly to account for the light lost due to the filter, we can make the blue sky darker and the white clouds show more contrast using a red filter.

Green filter No filter Red filter
Top left - Green filter, top right - no filter. Bottom - red filter. All filters applied in post with identical otherwise fairly pedestrian post processing settings, similar to what an out of camera JPEG might look like when using an actual filter in front of the lens.

The difference can be even more striking when reducing exposure for a more low key image, and subsequent processing, such as tone mapping and enhanced local contrast is applied.

Green filter tone mappedRed filter tone mapped
Green filter on the top, red filter on the bottom. Other than the choice of color filters, all post processing instructions were identical.

The above photo was taken in daylight, which is full spectrum that contains some of all of the colors of the visible spectrum.

We can also use colored filters to help deal with different types of lighting conditions, especially with less than full spectrum light sources. This image was shot on an outdoor stage at a concert festival at night with the fog machines going wide open and mostly red and much less green LED lighting active at the time of the image capture.

enter image description here
EOS 7D Mark II + EF 70-200mm f/2.8 L IS II, ISO 3200, f/2.8, 1/500 second. In camera-settings applied in raw conversion.

Converting to B&W with a green filter applied reduces the influence of the fog and shows clearer detail, though it does come at a signal-to-noise ratio penalty due to needing to increase exposure because there wasn't much green light in the scene.

Green filter with contrast and exposure adjustments

A red filter, on the other hand, increases the influence of the fog. This is with the same exposure setting as used with the green filter.

Red filter with same adjustments as green filter

Pulling exposure back to compensate for the red filter still leaves a fuzzier image.

Red filter with reduced exposure

For Astrophotography

Another way we can use colored filters is when doing astrophotography. Green filters can help with increasing contrast of the moon. Clearsky filters reduce the influence of light pollution diffused by the dust and moisture in the Earth's atmosphere (much like the green filter in the example above with the red light and fog).

For Color film photography:

Even when using B&W film, or when using a digital camera to produce B&W photos, the world we are imaging is not B&W. It is in color. Sometimes those colors are highly saturated and intense. Sometimes those colors are muted and look almost monochrome, depending on the nature of light shining on the scene. But our human visual system sees the world in color.

Our human eye/brain visual system is also remarkable for adapting to differing lighting conditions when deciding what colors to assign to different things. Film is helpless in this respect. We need to put daylight balanced film in our camera when shooting in daylight. We need to use tungsten balanced film when shooting with electric tungsten lights. When shooting under flickering fluorescent lighting, we don't even have color films available that are balanced for the many different varieties of fluorescing lights that all have slightly different color output. But then, even daylight has different spectral content depending on things like the angle of the sun above the horizon, how many clouds are in the sky, or how much moisture, dust, and other pollutants are in the air. Shaded areas outdoors during mid-day have different color casts than the same areas when the sun is at a different angle and shining directly on them.

Filters to the rescue.

The filter you call "pink" is actually a light magenta filter. Back in the days of film, a Skylight filter was a slightly magenta filter that also blocked UV rays. UV shows up on many films as a blue to violet color cast. The skylight filter can be used to block the UV and enough of the blue color cast, especially on overcast days, to make the colors of things in the distance, such as mountains or a city across a bay, to look more like their colors under brighter sunshine. A skylight filter also makes it look like less of the non-blue light the distant subjects are reflecting is being scattered by the air between subject and the camera. Whether this inexpensive filter also blocks UV like a skylight filter does is unknown if it's not marked with a standardized filter number.

The "pink" filter might also be a correcting filter for use with old-style fluorescent light, which output a very greenish color cast on color film. Again, whether it is effective for use as an FL-A, FL-W, or FL-D filter is unknown unless it is marked as such. Your "purple" filter appears to be a stronger version of the same thing.

Blue filters are used to shoot under tungsten light with daylight balanced color film. Orange filters are used to shoot in daylight with tungsten balanced color film.

What about using colored filters with digital?

Usually one is better off shooting without any color filters with a digital camera and saving the raw data so that color filters, or the same effects as color filters, can be applied in the raw conversion process. You can even try applying different color filters to the same raw image file when using raw conversion apps that offer filter simulation options or allow third party plug-ins that offer such filter options.

Since most digital cameras sold to consumers in retail stores, whether brick & mortar or online, include a UV filter in the stack of glass directly in front of the sensor, you don't need a UV filter at all when using digital cameras.

Keep in mind that the effect of applying virtual color filters in digital postprocessing will be more specific about what colors they do and do not affect than adjusting color temperature and white balance. Changing color temperature and white balance shifts all of the colors in an image in one direction or the other. Color filters are more selective, affecting "opposite" colors to a greater degree while not affecting "like" colors very much at all.

There are a few specific exceptions when it might make sense to use physical color filters when capturing digital images, particularly if the final image is intended to be B&W. If one part of the visible spectrum is much brighter or more intense than the rest of the spectrum in the light illuminating the scene, by adding an "opposite" color filter the inordinately out-of-balance light can be attenuated and overall exposure increased to capture more of the other colors in the visible spectrum without blowing out the highlights in the offending color. This helps prevent noise that would be caused by raising the dimmer color out of the shadows of a dimmer exposure in postprocessing. That's how the "anti-pollution" filters used for astrophotography do their thing.

The closer one can get the light to like what one wishes it to appear in the final image to look like before it strikes the sensor, the better the image quality of the final image will be in terms of things such as noise, color banding, etc. But usually that advantage of using physical filters is outweighed by the advantage of not using a physical filter that leaves more varied options open in post-processing.

  • \$\begingroup\$ "No one... wanted their lips to be solid black in photos. By adding a red filter..." - or green lipstick :) (true!) \$\endgroup\$
    – Zeus
    Feb 8, 2022 at 1:09
  • \$\begingroup\$ I should caution on the use of general "light pollution" filters for astrophotography. The filters traditionally blocked the wavelengths associated with the (then) most common street lights such as Mercury or Sodium. But modern street lights use LED lighting with completely different wavelengths -- often rendering these filters ineffective. There are new generations of filters such as Optolong's L-Pro, L-eNhance, and L-eXtreme filters. These block the full spectrum except for the wavelengths associated with most deep-sky nebulae. \$\endgroup\$ Feb 10, 2022 at 15:30
  • \$\begingroup\$ @TimCampbell I doubt most beginning astrophotographers who don't already know this are shooting deep-sky nebulae. Most start out with much wider angle views and want to capture the Milky Way. And while it is true that many cities are transitioning to LED lighting, It seems to me that most rural areas, which are normally closer to the best dark sky locations, seem to still be using the older types of lights. \$\endgroup\$
    – Michael C
    Feb 11, 2022 at 9:51
  • \$\begingroup\$ @TimCampbell In the context of the original question above, which of the nine filters pictured do you think might be one of the newer astro filters? Pretty much all of the info in my answer is an attempt to answer, or at least make an educated guess, as to what the intended usages of the filters pictured in the example are. The magenta-purple one in the center might be an attempt to pass it off as a Clearsky type of filter, just as the one directly above it could be intended as either a type of FL filter or a Skylight filter. \$\endgroup\$
    – Michael C
    Feb 11, 2022 at 10:13

First, let me do an introduction.

As a broad explanation, a filter makes one thing. Eliminates part of the opposite part of a color wheel, the complementary color.

enter image description here

For example, a blue one will eliminate orange.

The question now is: In what situation do I have an orange color soo dominant I need to get rid of it? The answer could be when you use a tungsten illuminant.

So in order to use a filter, you need to know the color cast of the illumination.

One thing to consider is that a color wheel is not a 2D wheel, but a 3D solid, but we could live with only a 2D wheel, but taking into account the "density" of the filter, how low is the tint or how saturated it is.

enter image description here

In the case of the pink filter, it is normally not a pink filter. It is magenta. Pink is an unsaturated red. Magenta is a different hue, and it normally was used to eliminate a green color cast on some fluorescent lamps.

enter image description here

But also, color is to accentuate a dominant color of the filter. The purple one could be used on a garden full of lilies or something.

Brown could be also an unsaturated darker orange. So it will eliminate some blue. But also, as it is on the skin color line it could be used to "tan" a pale skin subject.

But if you are using a digital camera, do not use them. You will only reduce the amount of light entering the camera augmenting the noise and reducing the shutter speed, you will decrease the range of colors the sensor is capturing altering the colors, etc.

Those were used either on specific cases of color film photography or to augment contrast on black and white film. But they are not needed on a digital sensor. The only case would be if your digital camera is so limited it does not even have auto white balance. But that can always be fixed in post.

P.D. A gray filter could be or not ND. But IMHO use a specific ND filter, not just a generic gray one. A true ND has two characteristics. It states how many stops are reduced, and is as neutral in color as possible.


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