No traffic

No Traffic on the Bridge. How did I get this image? Did I Stop traffic or get up very early? Use Photoshop? That would be too easy. Besides Photoshop did not exist when I took this picture. No. The camera was on a tripod. I used slow film such as TMax 100 and f16. Then I put neutral density (gray) filter or even a polarizer. The filters restricted the light so that the shutter had to be slowed down. I used a shutter speed of 30 seconds with the filters in place. Since the shutter setting was so long, the moving cars didn't register on the film. The same was true of pedestrians. Only in the distance is it possible to pick out a pedestrian. The time was about 10 AM and there was plenty of traffic.