Testing an old large-format camera shutter

You don't need an specialist equipment for this! Just a digital camera.

Before being able to use any of my old shutters reliably I have to check the speed accuracy of the indicated shutter speeds. I do this using my digital camera. I take a shot of a scene with my Fuji XT20 set with a shutter speed that I want check on the old shutter. (1/50s)

I place the (removed) old camera shutter (without lenses) in front of the digital's lens.

The setup - lens removed from shutter which is then placed in front of the digital camera’s lens

With the digital camera on a long exposure of 5 seconds operate the old shutter.

I then compare the histogram of this image with that of the digital image shot at the "same" speed and note any difference.

In this case the shutter is firing at somewhere between 1/30 and 1/25s not 1/50s.