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Photography Question 

Robert Bussino
 

When to Apply Blue Filter to Cool Photo


When shooting with daylight film in tungsten light, when is a blue filter(80A) required to cool down the tone?

While shooting reptiles in a zoo, I've noticed that sometimes my shots are too warm. But sometimes they aren't. The lighting the zoo is using is usually floodlight but not always and I believe that the wattage of the bulbs varies according to the requirements of the species being lit.

Does the wattage of the bulb dictate how warm the picture will be? Does a 75 watt floodlight differ from a 100 watt "normal" lightbulb? Will a 150 watt floodlight produce a warmer tone than a 100 watt? Do you see where I'm going with this? What is the threshold for attaching the (80A) blue filter?


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April 11, 2002

 

Jon Close
  The bulb wattage is unrelated to the light's color temperature. The color balance is based on the filament or gas used in the light. Generally you'd use 80-series filters to correct for tungsten lamps and FL-D to correct for flourescent lights, but I don't think there are standard filters for halogen, mercury vapor, and other light sources. Mixed lighting (ex. flourescent + flash, or tungsten + sunlight from a window) is a compounding problem.

If you use print film you can skip the filters as much of the color correction can be done by a custom lab when printing. Fuji's Superia line of print film boasts a "4th color layer" (compared to the 3 used in most brands) that helps in reducing the odd color casts from different lighting sources.


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April 11, 2002

 

Colin
  In a recent test of colour negative films, the UK-published "Amateur Photographer" magazine gave best marks to Kodak Portra 160NC for minimizing the colour casts associated with difficult lighting (i.e. tungsten or fluorescent sources).


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April 18, 2002

 
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