How does static electricity appear on a developed film?

Our minds are so rarely silent. For those of us with anxiety disorders, the noise is constant. From what we&#;ll cook for dinner to the specifics of how our lives will end, there&#;s no shortage of things to worry about. But how does the creative mind function amid all this static?

With competitive price and timely delivery, Yuanlong Packaging sincerely hope to be your supplier and partner.

In my self-portrait series, Static, I explored this question by intentionally shocking 4×5 film with static electricity, creating double exposures with random patterns and shapes of light. 

The static can&#;t be controlled or shaped. Shocking the film means giving up creative control over the final image, knowing many sheets will be lost in the process. Yet the static is also magic, allowing us a glimpse at invisible emotions and abstract concepts. I&#;m particularly interested in how the sparks show the intersection of creativity and anxiety.

The process requires a fair amount of risk, from wrecking expensive film to getting a few shocks. To make one of these self-portraits, I start with a general idea and also the knowledge that the end result will probably look very little like what I&#;m envisioning. Self-portraits are like that anyway: you need to be ready to be vulnerable and give up some control.

First, I set up a background next to a big window. I take a meter reading and make the photo &#; usually four sheets of 4×5 film at each session. This gives me four chances to make it work. I shoot a Zone VI 4×5 Classic Field Camera with a Schneider Xenar 150mm f/3.5 lens from . All images are natural light, all shot on Ilford Ortho Plus 4×5 sheet film.

After I make the self-portrait, it&#;s time to wreck some perfectly good film! As most film photographers know, static during development is something film manufacturers and developers try to avoid. A spark can really mess up an otherwise great photo. But in this case, I need strong sparks to create the effect I want.

I use a Wimshurst machine, a static generator designed in the s that is now a fixture in many science classrooms. It has a big crank you turn with one hand. As it builds up a charge, sparks leap between two metal spheres. If you put your hand in there, you&#;ll get a zap, but it&#;s not going to kill you.

In the darkroom, under red safelight, I use a rubber glove to hold each sheet of orthochromatic 4×5 film between the two metal spheres. Instead of jumping directly from one sphere to the other, the sparks need to go through the film. When they do, they expose a pattern on it.

I have very little control over the sparks. A sudden crack makes a lightning shape, but it doesn&#;t always happen where you want. If you get the film wet first, the sparks are tiny stars and the emulsion gets a little streaky. If you shock for a long time in one spot, you might get a fireball.

However, even when you try to control it, you don&#;t get to pick what the static will do. It might create a cool flare or an amazing effect, but it can just as easily completely obliterate the image or overexpose the whole thing. There&#;s a lot of luck involved, and making photos like this requires openness to failure. It&#;s all about experimentation.

Finally, it&#;s time to develop. I use Ilford Ilfotec DD-X for this. When the film comes out of the final rinse, I get to find out if I wasted a few hours and a few dollars or if I managed to make something cool. It&#;s always a surprise!

What I love about this process is the way the sparks can show emotion and unseen thoughts. It&#;s a way to make invisible things visible. That usually invisible spark is what makes a portrait or self-portrait powerful, and seeing it manifested this way is nothing short of exhilarating.

The surface of films used in food packaging, industrial materials, and medical applications feature various properties, such as transparency, gloss, waterproofness, antifouling, and non-adhesiveness. Surface treatment and processing are applied to add various surface functions.

To evaluate the quality of the surface treatment and processing on film, it is important to measure surface roughness. This inspection measures the roughness of fine irregularities on the film surface and quantifies it numerically. One way to measure surface roughness is with a 3D laser confocal microscope.

In an experiment, I looked to verify if there&#;s a relationship between static electricity and surface roughness in films using polyethylene film (food wrap) and antistatic film. To perform the roughness measurements, I used the LEXT&#; OLS 3D laser confocal microscope. Read on to find out the results!

If you are looking for more details, kindly visit electro static discharge film.

Food wrap and antistatic film

Visually Comparing the Surface Condition of Antistatic Film and Polyethylene Film

First, I visually confirmed the surface condition of the two films using the OLS 3D laser confocal microscope.

The OLS microscope scans the sample surface with a 405 nm purple laser beam to acquire 3D data. Paired with a dedicated LEXT objective lens that adapts to a wavelength of 405 nm and suppresses aberrations, the system can clearly capture fine patterns and defects that are difficult to capture with conventional optical microscopes and general laser microscopes. The optical system is also non-contact, so there&#;s no need to worry about damaging the surface even with a soft sample such as a film.

Here you can clearly see that the surface of the polyethylene film doesn&#;t have a peculiar shape and has gentle irregularities. In contrast, the antistatic film has jagged irregularities of sub µm to several tens of nm periodically.

Quantifying the Surface Condition of the Antistatic Film and Polyethylene Film

Next, I quantified the difference in the visual unevenness of these two film surfaces by measuring the surface roughness using the same 3D laser confocal microscope. In this step, it is important to select a lens suitable for the sample under observation to obtain highly reliable measurement results.

The OLS microscope can easily determine* whether the selected lens is suitable for the sample thanks to the Smart Lens Advisor. In this example, the system determined the dedicated LEXT 50X objective lens was suitable for the roughness measurement of the film.

*Measured values are not guaranteed.

Using the 50X objective lens, the microscope obtained the following results for the two films:

The notable roughness parameters in the measurement are Sq, Sz, Sa, Sdr, and Sal. Here&#;s an overview of these parameters:

Sq (root mean square root height), Sz (maximum height), and Sa (arithmetic mean height)

These parameters indicate the size of the unevenness from the average surface. In this example, the antistatic film with a larger value indicates that the unevenness is larger.

Sdr (expanded interface area ratio)

Sdr shows the rate of increase in the surface area. In this example, the polyethylene film with a small Sdr value has a small surface area. In contrast, the antistatic film has a larger surface area due to the large unevenness on the surface.

Sal (autocorrelation length)

While most parameters evaluate roughness in the height direction, Sal is one of the few parameters that focuses on the lateral direction, such as the density of streaks and particles. A smaller Sal value indicates a steeper shape and finer grain. In contrast, a larger Sal value indicates that the surface has a more gradual uneven shape. As a result, we can conclude that the antistatic film with a smaller Sal value has more fine-grained shapes on the uneven surface.

Determining the Static Electricity of Film with Surface Roughness Data

The three major factors that determine the amount of static electricity are contact area, friction force, and humidity. Here, we focused on the contact area, which is closely related to surface roughness. In general, a larger contact area between objects generates more static charge.

In this experiment, we can see the antistatic film with a small contact area between objects generates less static electricity compared to the polyethylene film with a large contact area. The large unevenness of the antistatic film lowers the contact area compared to the smoother surface of the polyethylene film. Below you can see the relationship of the charge amount with the surface roughness data:

If you want to learn more, please visit our website esd aluminum foil zip-lock bag.