Photo Tip ~ Red, White Lighthouse Conundrum

In the last couple years I’ve taken a great interest in lighthouses. There are many factors that make them interesting to me; the history and stories, their relationship with the sea, the symbolism of safety and guidance, and their unique characteristics. I often imagine what it would be like if the lighthouses could talk. Every lighthouse is different in one way or another specifically so sailors can identify each light, while traveling at sea.

We recently traveled to the Upper Peninsula of Michigan (A.K.A. the U.P.). The people there call themselves “YooPers”. Ya gotta love that. The forecast called for a front with rain the following day, so we burnt the candle at both ends.

My youngest son, and fellow photographer, woke with me at 4 (yes, a.m.) and we drove an hour east to visit and shoot the Bete Grise Lighthouse (not shown here) for the a.m. “Blue Hour”. To me, blue hour is one of the most rewarding times of the day to shoot, it’s well worth the discomfort of getting up extremely early.

During the day we toured a variety of areas and had dinner at a little greasy spoon diner en route to the Eagle Harbor Lighthouse – yes, you guessed it, for the p.m. blue hour. And it was really P.M., being as far north as we were the blue hour didn’t start until after 10:00p.m. Needless to say we slept in, until 8:00a.m., the next morning.

The Problem

The Eagle Harbor light caught me off guard and presented me with a problem that was a bit of a puzzle at first. In 1962 the original fourth order Fresnel lens (a large solid white light) was replaced with two DCB-224 aero beacons. This was part of the cross country lighthouse automation that eliminated the need for lighthouse keepers. Sadly most lighthouses today are unmanned and use electric automated lighting, but I digress.

Here’s the problem, there are two rotating lights, one red and the other white, and each is visible for about 10 seconds. At sunset it was no problem with a fast shutter speed. When the white light would come by I’d shoot it and then I’d get a shot of the red light. Well, when blue hour came, my exposure time slowed dramatically to thirty seconds. See the problem? With a thirty-second exposure and each light continuously rotating in ten-second intervals, the top of the lighthouse turned into a strange huge illuminated pink blob.

I wanted to get a shot of just the red light and a seperate shot with just the white light and I really didn’t want to have to mess with it in Photoshop. The sky went flat, like it often does at dusk. Some nice clouds earlier had disappeared and the sky was a pretty even blue. I had been using my neutral density (ND) split gradient filter to darken the top portion of the sky. I was looking at the filter and it’s protective case sleeve when it hit me. I could kill two birds with one stone.

The Solution

The solution was to take the ND filter off the lens, it wouldn’t be needed any more. Instead I used the ND filter case, which is black and larger than the lens, to “dodge” the image during the long exposure. Dodging and burning are darkroom terms for removing or adding, respectfully, extra light from or to an exposure.

Here’s how it worked ~ during the thirty-second exposure, when the red light rotated into sight I removed the case from in front of the lens. When the red light disappeared and just before the white light became visible again, I lowered the filter case down in front of the lens just far enough to cover the white light coming from the beacon. Thus, no white light was exposed to the camera. I gently moved the filter case up and down slightly during this time to soften the edge and make the gradation in the sky appear more natural, instead of hard edged.

The result was a single, in-camera image (posted at top), with just the red light visible and a nicely graduated deep blue sky. Two birds, one filter case. So, with a little luck and some improvisation I was able to get the shot at Eagle Harbor I wanted, one red beacon shining into the night.