No. 194

Dr. Love's Diagnosis - Vertical Stripes

Patrick Tobin, | Nov 8, 06:54 PM

Occasionally, your Impossible film shots may exhibit a dark vertical stripe, or band covering 1/3 or more of the image. Impossible USA’s Camera Resources Manager Frank Love explains what causes this phenomenon…

There are several causes for these kinds of effects but they all relate to the chemical pod. First let me explain that the chemical developer which performs the amazing feat of producing a positive print from a film negative in a few minutes is locked away in what we call pods. The chemical pod is the entire reason behind the larger white border at the bottom of integral instant frames. Along that border there are 3 separate ‘pods’ which hold the developer. It is the process of being ejected and running through the camera’s rollers that spreads this paste over the film sheets to initiate the image processing.

The fact that there are 3 separate pods is also the reason why sometimes a full third of your image looks different than the rest. The names for this effect is referred to as ‘striping’, ‘bands’, ‘crazy pods’, and ‘poor pods’ depending on who you are or perhaps the severity of the stripe. The base reason for one of these stripes is typically due to the chemical in that one, or sometimes two pods, to have effectively aged and/or processed differently than the other(s) in the frame. It results in a different degree of processing which visually results in different density levels within the same sheet of film.

Sometimes, the developer in one or more pod has been exposed to what little bit of air there is for too long, or just too much air, and this causes the paste to dry out prematurely resulting in a very different development than is intended.

In the end the best thing anyone can do to try and prevent this effect is simply ensure the best storage for your materials and to use fresh materials as well, and specifically with Impossible film, keeping film shielded well can help to keep subtle differences in these stripes from becoming more apparent.

Keep your rollers clean,


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