Identifying filmholder light leaks

[Ed Richards]

What does a light leak from the sun shining into the end of the holder look like, i.e., when you pull the slide, do not cover the camera, and wait a bit to shoot?

[Glenn Thoreson]

On the negative, it would look like a dark flare. It rather depends on how bad the leak is. If you have suspect holders, put paper in them (cheaper than film) and put them out in the sun for a while. If you mark your paper negs beforehand with the holder number and orientation, it will be easy to tell exactly where any leaks are when you develop them. All this can be done under a safelight, making it easy.

[Ed Richards]

> All this can be done under a safelight, making it easy.

Assuming you have a dark room - I use a changing tent and daylight tank.

What I am seeing is a band of slightely increased contrast just inside the edge of the negative that faces the darkslide slot. Pretty even all the way down, and quite narrow. I have used binary notches in my holders so I suppose I can track the holder and test it.

[Jim Noel]

Developing the practice of ALWAYS leaving the dark cloth over the camera will take care of essentially all holder light leaks.

[C. D. Keth]

There is a solid method to identifying leaky holders here: http://www.largeformatphotography.info/leaks.html