(This was a cross-post from Google Plus. You should circle me!.)

As Thomas Kang describes in his post, we launched the Google PhotoSpace project at last night’s opening of the new Los Angeles Google Office. (Tom took some terrific photos of the event as well, you should go check ’em out)

Because I did a lot of lighting in film school (way before I became a software developer), I was largely responsible for the physical setup and lighting of the stage area. This turned out to be an interesting problem. We wanted the “white limbo” look for the photos, and we wanted to photograph as many guests as possible the night of the party (hundreds in just a few hours). Rather than cycling a strobe system all night, and because I’m most familiar with them, we decided to use “hot” movie lights.

We did a number of tests of both green and white screen solutions and ultimately settled on a white screen plus a luma key extraction that Ken Arthur tweaked to perfection minutes before the guests arrived.

To make the luma key work as well as it did, we needed a fairly broad exposure differential between the background and the subject. I broke out the light meter I bought in high school and decided that 2 stops would be a good split, with the subject on the underexposed end of things so that the luma keying wouldn’t eat into the subject highlights too badly. Ken and Tom did a lot of work on this; Tom behind the camera and Ken turning the many dials on his image processing code.

We needed very even light on the background. I used two open-faced 1K tungsten units with half double scrims (scrimmed edge closest to the backing) and a tough frost diffusion tented. These were the main background lights and were up high. Since they fell off towards the bottom of the screen I added two 650w fresnels lower down at about one meter off the ground, no scrim, also diffused.

While there was a lot of lovely white spill curling around the sides of the subjects, I also added a high 350w diffused kicker behind the subject.

A 1K open face with a Chimera softbox and the full silk added a nice fill for the subject’s face.

The last piece I added to the stage was a pair of 18×24″ flags on C-stands, hanging down near the sides of the units illuminating the backing. These cut down on side spill enough that we could correctly underexpose our visitors and pull them away from the backing.

Keith Kiyohara instigated the entire mad project and wrote the kiosk software driving the camera and feeding the image processing pipeline. He also wrote a native application to display the panorama on a triptych of 70″ monitors mounted vertically. (stunning!).

Reuben Sterling wrote the webapp version of the panorama, so you can see it too.

Thanks, everyone, for a fantastic and Googley 20% project! I even got to shake the mayor’s hand!

Gavin Doughtie
Photos Team

P.S. If anybody reading this knows interesting things about LED lighting please say so in the comments. We’d like to make this installation permanent and the movie lights pull close to 50 amps. That’s just not the energy-efficient way we roll at Google.