Static On Film

Have you ever gotten strange artifacts on your films that look like this:

This is the result of static electricity and if you have acclimatized yourself for long enough in the darkroom; you can even see when the static electricity sparks go off on the film.

These artifacts are a pain because they can ruin a perfectly good experiment. For something like western blotting, getting an artifact like the above that covers up your result is annoying but most of the time, you can make a few repeat exposures before the ECL substrate gives out on your membrane. However, if you are working with something that takes weeks to months to develop on film (e.g. S³⁵ in situ hybridization), getting an artifact that covers up some of your most important image results can be very devastating as the entire experiment will probably need to be repeated.

I have had the unfortunate experience of having these artifacts crop up in my experiments. Over time, I came to realize that the main problem lied with the lab’s air conditioning.

Static electricity is a build up of electrons (negative charge) within or on the surface of an object that is retained until it can be released by an electric current or electrical discharge. Water is a conductor of electricity, so in a humid environment, the moisture in the air absorbs and can evenly distributes excess charges, thereby allowing excess charge to leave objects.

My Experience

During my time working in a lab housed in an old building, I have never once gotten an artifact like the above on any of my films (and I had done a lot of film work). Fast forward to my new lab, which was brand new, the artifacts appeared almost all the time I did any film work. My technique, equipment, and reagents were pretty much the same so the only real difference was the lab itself. I ultimately concluded that the problems came from the level or moisture in the air. In my old lab, there was no air conditioning or windows that actually opened. As such, the lab was always humid. In contrast, my new lab was fully air conditioned and the air was always very dry. I tested my theory by having the air conditioning turned off in the new darkroom; while it did get pretty hot and humid in there, importantly, the artifacts stopped.

Suggestions

If you are having problems with artifact on your films cause by static electricity:

* You can try using films containing an anti-static layer, although I still found the artifacts cropping up on them.

* Try preventing the static build up beforehand. If you are using transparency film to sandwich your western blotting membranes, leave them in a humid area. The same goes for the autoradiography film or hyperfilms.

* If possible, switch off the air conditioning (at least for the darkroom).

* If possible, use a humidifier.