Color Conversion Filters



Although the 80A filter is mainly used to correct for the excessive redness of tungsten lighting, it can also be used to oversaturate scenes that already have blue. The photo on the left was shot with a polarizer, while the one on the right was shot with a polarizer and an 80A filter.

Color correction

A major use is to compensate the effects of lighting not balanced for the film stock's rated color temperature (usually 3200 K for professional tungsten lights and 5500 K for daylight): e.g., the 80A blue filter used with daylight film corrects the orange/reddish cast of household tungsten lighting, while the 85B used with tungsten film will correct the bluish cast of daylight. Color correction filters are identified by numbers which sometimes vary from manufacturer to manufacturer. The use of these filters has been greatly reduced by the widespread adoption of digital photography, since color balance problems are now often addressed with software after the image is captured, or with camera settings as the image is captured.

Color temperature and Mired
A “Color temperature” of 5600 K (Kelvin) is assigned to the “white” light of the sun, because the temperature of the surface of the sun is approximately 5600 Kelvin. The Kelvin scale corresponds to the Celsius scale (°C or degree centigrade), except that it does not begin with zero as the freezing temperature of water, but with the absolute zero (-273.¡6 ºC). Because the incandescent filament of a halogen bulb must not reach the melting temperature of tungsten (the most heat-resistant metal) which melts at 3653 K and which becomes soft before reaching that temperature, halogen bulbs can only be used up to 3400 K. At this temperature the blue component is much smaller than that of sunlight, so that this light appears in the complementary color orange. The incandescent filament of a conventional light bulb only reaches about 2700 K, its light appears even redder, in other words, more orange-red. Daylight color reversal films are balanced for 5600 K and they record every color cast that our eyes perceive as much weaker, because our brain performs a corrective “white balance”. Mired values make it much easier to calculate needed filter densities, because the same differences in Mired values, e.g. between the mired value of the light source and that of the film, correspond to the needed filter value. The number in the designation of the filter is the value of the filter measured in Dekamired (¡ Dekamired = ¡0 Mired). In blue filters, this value is negative, i.e. in calculations it has to be used with a minus sign.

Color Conversion Filters
Color Conversion Filters These filters are used to balance the color temperatures when you are using certain films under different light sources. An example of this would be using daylight film under tungsten lighting or vice versa. Color conversion filters are designed to convert the temperature of the film to light or of the light to film. This will allow all the colors to fall in proper perspective and look natural. These filters are generally available in two series:
Cooling Filters

80A Conversion Filter (KB 15)  - The conversion filter with the most delicate shade of blue attenuates the slightly higher red, orange and yellow components in order to produce a neutral color rendition. it also can be used for subjects that are to be shown with a cooler coloring. In addition, they adapt the color temperature of the very bright photoflood lamps to color films balanced for halogen light of 3200 K. Its filter factor represents 1.1.

80B Conversion Filter (KB 12) The deep blue filter blocks so much red, orange and yellow that increases the color temperature of very bright halogen and special photoflood lamps (of around 2400 K) to that of daylight. With that kind of illumination, and with daylight color reversal film, the subjects will be reproduced in their original colors. With weaker halogen bulbs or stronger incandescent bulbs in conjunction with this filter and with daylight reversal film. a residue of "warmth" will be retained for an optimal mood in interior photographs. Its filter factor is approximately 2.

80D Conversion Filter (KB 6). This nearly medium conversion filter neutralizes the strong red tendency of light at sunrise or sunset out in the open when the original colors of the subject are wanted instead of a warm morning or evening mood. In addition, the KB 6 filter is ideal for under-corrected filtering of artificial light photographs on color negative films. When filtration is performed only later during printing, there is a visable color shift, and full correction leads to a higher loss of light. its filter factor is approximately 1.5.

82A - Color Conversion Glass Filter is a light balancing filter used to increase the color temperature slightly for a cooler tone. This blue filter absorbs the excessive yellow-red light from daylight in the morning.

There is much flattering light to be found in the early morning and afternoon hours. With sunlight low on the horizon, the red-orange end of the spectrum becomes enhanced. With daylight balanced film, images shot in this light may prove to be a bit on the warm side. The photographer may desire this effect or choose to "cool" things down.

An 82A has a greater "cooling" effect than an 82 but less than an 82B. The 82 series of blue filters allows the photographer to keep skin tones somewhat normal by increasing the color temperature to a more daylight balanced level. In addition, an 82A provides a cooler effect with tungsten film under 3200K lamps.

82B Cooling Filter These are light balancing filters used to increase the color temperature slightly for a cooler (bluer) tone. Corrects the tendency toward reddish tones. These series filters are also used to prevent the reddish tones in early morning or late evening light for natural skin tones. - 2900 K to 3200 K - • 82B Increases temperature from 2,900 to 3,060 Kelvin (2/3 stop).

82C Conversion Filter (KB 3) - With about twice the correcting effect of the previous filter, this conversion filter removes the orange-red color cast that appears on photographs made on tungsten reversal film with artificial light using 100 to 2oo W light bulbs, or from aged photoflud lamps. Therefore this filter is ideal for neutral color reproduction with approximate illumination. Its filter fiactor is approximately 1.2 • 82C Increases temperature from 2800-3200 Kelvin (2/3 stop).

Conversion Filter KB 20 This is the correct filter when the illumination is provided by 40 to 150 Watt household incandescent bulbs, and the transparencies are to show the subject in its original colors (e.g., technical interior, architectural photographs, or reproductions). It should not, however, be used for moody interior pictures because unlike the KB ¡5 and KB ¡2 filters, the KB 20 filter corrects the light to a neutral balance, elimi-nating the warmth that we might intuitively expect from bulbs. Its filter factor is approximately 2.7.  

Warming Filters

81A warming filter. Increase the color temperature slightly; this can also be used when shooting tungsten type B film (3200 K) with 3400 K photoflood lights. Pale orange color. The opposite of 82A.. This filter balances color temperature from artificial light sources to the color tungsten film standard of 3200 degrees and balances the difference up to 3400 degrees. Due to this characteristic, a noticeable warmer color reproduction is produced. This fine balancing is important for special work such as art reproductions where true color reproduction is required. Filter factor is approximately 1.2.

81B warming filter. It's Autumn. The clouds are low hanging and the sky is "patchy blue". You've gone for a ride upstate to the mountains and the light in open shade is bluish. A photo taken of your girlfriend with daylight balanced film leaning against the side of a barn will yield bluish tones that she might not find particularly flattering.

An 81B filter will replace even more yellow than an 81A and bring her skin tones back to a more appealing level. An 81B can also be used with electronic flash to reduce the amount of "blue" generated by the flash. The 81 series (81A, B, C, D and EF) allows you to choose how much warmth you wish to replace in the image.

81C Warming filter, slightly stronger than 81B, opposite of 82C.This filter is strongly recommended for daylight photographs, especially in spring and summer with cloudless skies and clear air. It helps eliminate the strong blue tone and haziness that is produced by this level of ultraviolet light. Furthermore, it will reduce the unwanted blue tone in shadow areas with an overcast sky. Filter factor is approximately 1.2.

81D Color Conversion Filter This filter controls the bluish coloration that affects daylight film. An 81D is used as a warming filter to eliminate the bluishness of open shade on very clear days. The 81D is stronger than an 81C and is also used for general landscape photography on cloudy days as well as to add more of a "suntanned look" in portrait photography.

An 81D filter will more than replace the yellow missing from the image and place all skin tones on a "warmish" level. The 81 series (81A, B, C, D and EF) allows you to choose how much warmth you wish to replace in the image.

81EF Warming Filter The 81 Series of Filters control the bluish coloration that affects daylight film. They can also remove excessive blue from the effects of electronic flash. Sometimes a Director of Photography may prefer to use an 81EF rather than an 85. When used alone in daylight, this filter under-corrects tungsten balanced film and provides a cool or bluish look. However, if an 81EF is used with tungsten balanced film in tungsten light, it results in a warm look.

An 81EF filter (the strongest in the 81 series) will more than replace the yellow missing from the image and place all skin tones on a distinctly "warmish" level. You might even consider using an 81EF at the beach to make a hot scene even "hotter". The 81 series allows you to choose how much warmth you wish to replace in the image.

Combination 85C/Neutral Density .3 glass filter A very unique filter that offers possibilities that other filters don't.

Neutral Density filters have several uses and offer the possibility to achieve otherwise unachievable results. ND filters appear grey and reduce the amount of light reaching the film. They have no effect on color balance. 85C Color Conversion Filter What do you do when you must take some photos outdoors and all you have left is tungsten film? Using tungsten film in daylight will produce a bluish cast in the photograph.

The 85 series of filters will "bring back", i.e. color balance the tones in your images. These yellow filters are used to correct differences in color temperature between the recording medium (film/video) and the light source. An 85C produces the coolest results of the 85 series - more than either the 85 or 85B. However, it is interesting to remember that an 85C is also useful as a creative warming filter with daylight film in daylight.

85B Color Conversion Filters Sunlight, daylight, incandescent, fluorescent, and other artificial light sources all have color characteristics that vary significantly. Filters give you better images by adjusting for these light variations. Film and video are rated for a particular color temperature such as that of daylight or tungsten light. Filters are used to correct differences in color temperature between the recording medium and the light source. An 85B filter converts tungsten film to daylight. An 85C produces the coolest results - more than either the 85 or 85B. However, it is interesting to remember that an 85C is also useful as a creative warming filter with daylight film in daylight. 

B+W 81C Warming Color Conversion Filter (KR3) , slightly stronger than 81B, opposite of 82C.This filter is strongly recommended for daylight photographs, especially in spring and summer with cloudless skies and clear air. It helps eliminate the strong blue tone and haziness that is produced by this level of ultraviolet light. Furthermore, it will reduce the unwanted blue tone in shadow areas with an overcast sky. Filter factor is approximately 1.2.

B+W 81D Color Conversion Filter This filter controls the bluish coloration that affects daylight film. An 81D is used as a warming filter to eliminate the bluishness of open shade on very clear days. The 81D is stronger than an 81C and is also used for general landscape photography on cloudy days as well as to add more of a "suntanned look" in portrait photography.

An 81D filter will more than replace the yellow missing from the image and place all skin tones on a "warmish" level. The 81 series (81A, B, C, D and EF) allows you to choose how much warmth you wish to replace in the image.

Fluorescent Filters Fluorescent filters are used to correct the greenish tone that can show up when you are shooting daylight film under fluorescent lighting. There are various types of fluorescent filters. They can balance daylight film under warm white or white type fluorescent lights and correct the color balance when using tungsten film under fluorescent lighting. Fluorescent filters are basically general purpose filters that are designed for moderate correction. They may not always provide perfect color rendition by themselves. Because fluorescent lights shine at various temperatures they often need more filtration for proper results.

Hitech FL-B Fluorescent Resin Filter for Tungsten Film .

FL-D MC Filter - Fluorescent Light Filter 499 F-Day This Filter eliminates the green cast that occurs when daylight-type color film is in fluorescent lighting. Examples are interior photographs made in offices, reception areas, factory halls, subway stations and swimming pool halls, as well as night-time photographs of office buildings whose windows would appear green because their interiors are usually illuminated with fluorescent tubes. The abbreviation F-Day stands for “Fluorescent Light - Daylight”, which reflects the fact that these filters are designed for the most commonly used type of fluorescent tube, which emit light of a color that, as mentioned above, resembles daylight. Because fluorescent tubes are not “thermal radiators”, they do not produce a continuous spectrum like those of the sun and incandescent bulbs. Instead, they emit a sharply defined line spectrum that has high intensity spikes in the green region. Our eyes barely perceive this special green, so the fluorescent light appears to us as nearly neutral in color. However, most color films are especially sensitive to those wavelengths and they react with a strong pronounced cast. Photographers using color temperature meters for three color metering (simple meters that measure only two colors are not suitable for this purpose) can also undertake the correct filtering with of a combination of LB- and CC filters (see pages ¡7 - 23). With this method, they can also correct the light emitted by other types of fluorescent tubes, such as Warm Tone, Standard Light, White Light, etc. But for hobby photographers who do not wish to make a large investment in such an instrument and who do not care to carry along a selection of LB- and CC filters, the B+W F-Day Filter is far less expensive and much more practical. Its filter factor is approximately 2.

FL- Warm MC Filter - color correction

 

 

Shop for Color Correction Filters at these stores
Link to Adorama Link to Amazon Link to B&H Photo Link to ebay