Working under Mercury-Vapor Lights

As you know if you read my blog regularly my favorite way to set my white balance is to do a custom white balance setting using the ExpoDisc. Here is a quick reminder–skip down if you want to see another way to set your white balance.

Remember under fluorescent and mercury-vapor to set the white balance at shutter speeds of 1/100 or slower. You can later shoot under faster shutter speed after custom white balancing the camera.

ExposDisc goes in front of the lens and then you use it to get an incident reading rather than a reflective reading of the light.


Notice the direction of the light hitting the subject.  You move to the same position to get the light reading below.


Point the camera toward the direction of the light that is falling on the subject.

The latest upgraded version has introduced the warming filters that you place in front of the ExpoDisc. They are light blue and since the camera tries to neutralize the colors will add yellow to your photos thus warming them up. the actual color is really a blend between cyan and blue adding a little red/yellow to your photos. They come in different densities to allow you to add just a little or more depending on your taste.

Presets in Nikon D4

Check your manual for your camera because this is for the Nikon D4. Somewhere in your menu you can go and adjust using presets for white balance.


On my Nikon D4 in the menu for White Balance you can choose up to seven different presets for fluorescent.  There is a major problem I have found trying this method, it isn’t easy to pick the right color, because the monitor on the back of the camera isn’t that easy to see color in all situations.

Fluorescent lamps are manufactured to a chosen color by altering the mixture of phosphors inside the tube. Warm-white fluorescents have color spectrum of 2700 K and are popular for residential lighting. Neutral-white fluorescents have a color spectrum of 3000 K or 3500 K. Cool-white fluorescents have a color spectrum of 4100 K and are popular for office lighting. Daylight fluorescents have a color spectrum of 5000 K to 6500 K, which is bluish-white.

Note that on the Nikon D4 you also have a pre-set for those awful Mercury-Vapor lights. Sometimes I have found that I prefer one of the fluorescent settings under some of the newer mercury-vapor lights when using this system instead of the custom white balance.