When I first walked into my first studio in downtown Charlottesville, Virginia back in 2009, it was love at first sight. The place was a total dump: it had been used as a mechanic's garage, a tractor rental company, and for other industrial purposes over the years. But I knew that could be fixed. It was the light I was after. So, I strapped on my work gloves and went to town.
The studio had two giant windows that faced north, and was elevated on a hill. The light that entered those windows was all reflected off the surrounding sky, and was so strong that you often turned your eyes away from the windows because of the intensity. And it never changed, no matter the weather or time of day: the light was always the same.
Further, anything you put in front of those windows to photograph in the midst of that north light looked dreamy and filled with aura. It was like visiting the well-kept house of an elderly woman who has had her place decorated the same way for 50 years: all of the furniture, decorations, picture frames, and people, feel like they're supposed to be there, or had been there for decades, and you just happened upon it one day. No matter how imperfect the position of the things, or the imperfections of the things themselves, the sheer length of their stay in that same place for so long renders them the "right" things in the "right" place for them to be. It is a sort of validation of the authenticity of the thing placed.
That's what it was like to have a subject in that studio.
After they tore the place down in 2013 to make room for a Marriott Hotel, I've been on the hunt for the same kind of light. At one point, I had access to a luxurious place with giant, south-facing windows. I placed a few white curtains over the brightly-lit industrial windows to diffuse the strong sun, but something about the light just wasn't right.
What was the difference? Why was it that I couldn't recreate that north-light-glow using south light? I loved using the faster shutter speeds that the super-bright south light allowed. But the behavior of the light was so much different from my original space.
So, I decided to try to answer this question by studying the difference between north and south light, starting with trying to understand the behavior of north light.
Below is a meter reading diagram taken by a north-light window in our house.
A few observations on the diagram above, looking at the left or right side of the room where we would have a subject stand (ignore the readings in the middle of the room):
1) There is a 3-stop difference between the brightest highlights and the deepest shadows.
2) The highlights dominate the light falling on the subject, therefore, most of the subject will be lit by highlights.
3) Once the light begins to fade, it seems to step down those 3 stops gradually, not abruptly.
After recording this, I walked over to a south-lit room of the same house, at the same time of day, and made this recording:
If we look at the measurements if the subject is standing on the left (ignore the middle and right for now), we see:
1) There is still a 3-stop difference between the brightest highlights and the deepest shadows.
2) The highlights still dominate the light falling on the subject.
So far, it's all the same. Until we get to the third observation:
3) Once the light begins to fade, it steps down abruptly: starting at 1/500 of a second for highlights, to 1/250 for midtones, then suddenly, there is a two-stop difference at the next 45 degree angle of the subject.
Put another way: north light fades more gradually around the subject than the shadows of south light. The north light shadows present more slowly than the shadows of south light, creeping in with more nuance and character. In contrast, south light has a "steep roll-off."
This is why I've been preferring north light for my primarily black-and-white photography: black and white film will reflect these subtle, gradual changes in exposure zones as variations in whites, greys, and blacks. That's why we see a difference to the naked eye, and the final product, when shooting black and white.
Now, these were rather crude, low-sample-size measurements, but I'll be getting into more detail about the behavior of north light and how it interacts with each film's unique characteristic curve at our upcoming LB workshops this summer and fall.
We'll also be talking about why my friend Sandra Coan here at Little Bellows much prefers south light to north light for her beautiful color photography! The reason will blow your mind!