A little bit about my process for Ochava Solstice

August 8, 2011

On sunny days, I’ve been busy working on my project Ochava Solstice. I thought I’d write a little bit about how I’ve been going about it recently. Here’s a picture of me shortly before taking a picture for the series.

Me about to shoot an Ochava

The building in question is on the north-facing corner of Marcos Paz and Asunción in the Buenos Aires neighborhood of Villa Devoto. Here’s a gratuitous close-up of the image on the ground glass. Since I’m standing in the shade and the building is in the sun, I don’t need to use a darkcloth.

Image on the ground glass of the building with the ochava shadow

For all the camera geeks out there, I’m shooting this series on a Busch Pressman Model D. It’s a press camera from the 1950s similar to a Speed Graphic. The main difference is that the back rotates, letting me shoot vertically, which I do a lot. I’m using a 210mm lens which is slightly telephoto for the 4×5 format.

I had already scouted out this building online. When I first started this project I’d look for these buildings on foot. At first these triangular shadows were just something I noticed in my walks around the city and I’d snap them with my digital camera. Once I got serious about the project, I returned to those same buildings with my 4×5 and a tripod, and waited for the moment when the shadow is exactly in the middle.

The buildings in the series are functional apartment buildings from the 1960s that just happen to cast a triangular shadow. It’s not intentional. It’s the result of a law requiring corner buildings to have a diagonal cut on the ground floor [known as the “ochava”] combined with real estate developers’ desire to maximize square footage [or meterage, I suppose].

Apartment buildings from this era are everywhere in Buenos Aires but ones suitable for my project can be hard to find. They have to face the sun and not be in another building’s shadow. There’s almost always a kiosko on the ground floor or something else “wrong” with the building. In finding the ones I’ve taken so far, I’ve scoured a number of neighborhoods, on foot, in great detail. Recently, in the name of efficiency, I’ve taken to using the Mapa Interactivo run by the city government. It’s less efficient than Google Street View [which doesn’t exist here yet], but still faster than walking around. In the map, you zoom in on a block, click on a plot of land, and it shows you a photo from several years ago. Here’s the photo of this particular building I found on the site.

Marcos Paz & Asuncion

As I’m navigating the site, I confine my search to neighborhoods where I think I’m likely to find buildings like the one above [not too urban, not too suburban]. I only click on the street corners that face north, towards the sun [remember we’re in the southern hemisphere]. To keep track of my progress, I’ve been marking up a map with little dots:

Map I'm using to check off street corners (the black dots)

Of all those little dots on the map above only two were buildings suitable for my project. It’s a bit like panning for gold.

Meanwhile in my apartment I’ve taped up the contact prints of Ochavas I’ve already shot in order to track my progress. Here are the ones I did last year:

2010 Ochavas

And here are the Ochavas I’ve done so far in 2011

2011 Ochavas (so far)

My goal is to reach 50. It’s a bit arbitrary but I want to show a large number of these shadows and 50 seems like a good number. I’ve got around 40 so far. There are a number of good buildings I’ve already scouted out but I need to wait a few months for the sun to get higher in the sky.

Buenos Aires is totally flat and built on a grid, although it’s actually several different grids. The grids don’t all face the same way. The time of a particular corner’s “solstice” is determined by its cardinal orientation. The height of the shadow is determined by the time of year, with summer casting longer shadows. [Curious tidbit: maps in Buenos Aires don’t all face north. There’s at least three different orientations commonly used when depicting the city.]

Most of the street corners in my project so far are north-facing corners taken in winter [June & July]. A few are east or west-facing corners taken in the summer morning or afternoon, respectively. The arc of the sun is much higher in summer so the window of time when the sun is at the right position to cast an appropriately sized shadow is shorter. I drew this diagram below to explain this to a friend, although I’m not sure it makes the concept any clearer.

Porteño Calendar

I’ve previously compared these triangular shadows to the serpent-like shadow that appears on Chichen Itza at the equinox. It seems that I’ve now drawn up a sort of Aztec-like calendar for Buenos Aires. There are no geographical references in Buenos Aires. The river is distant and cut-off from the main part of the city and there are no mountains to provide a reference point. Walking around the grid of the city can sometimes feel like being lost in a kind of labyrinth. If I’m beginning to lose that sense of being lost it’s only because I’ve now memorized good chunks of that grid, recreating it mentally in my head to orient myself. These street corner photographs are like totems of my wonderings around Buenos Aires.

I’m now scouring [online] the very edges of the city, places I’ve yet to reach during my 3+ years of walking around the city. Obviously I only shoot this series on sunny days. If it’s cloudy I work on other stuff. Partially cloudy days are a real source of frustration because I never know if I should risk spending an 90 minutes on a bus to reach the neighborhood only to have a cloud erase the shadow at the critical time. There’s only about a two minute window when the triangle appears visually to be in the middle.

For this building the day was in fact partially cloudy but they were very low and moving fast in the stiff wind. Arriving at the corner early I sat in the sun as the day was very cold. I shot this video below which shows the shadow disappearing as a quick cloud passes by:

I was fortunate that day in that by the time the shadow reached its midpoint the clouds had departed. Here’s a snapshot of the contact sheet I just got back from the lab. One more corner to cross off the list.

Contact sheet of Marcos Paz & Asuncion Ochava

I’ve also written more about this project in these two blog posts; Ochava Solstice and Ochava Solstice – Things that Go Wrong.

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2 Responses to “A little bit about my process for Ochava Solstice”


  1. […] in late May, mostly to finish my Ochava Solstice project. I was a lot more methodical this year (see post), and set myself a goal of 50 street corners for the whole series. Preparing to photograph a corner […]


  2. […] in late May, mostly to finish my Ochava Solstice project. I was a lot more methodical this year (see post), and set myself a goal of 50 street corners for the whole series.Preparing to photograph a corner […]


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