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Category: In the Lab

Here I test out new chemistry recipes, methods or try to verify facts.

Understanding the effect of temperature in film development

Temperature is one of many parameters that influence the rate of film development. Manufacturers standardize their adviced development times under the assumption you are developing at 20 C / 68 F, and they supply handy tables and graphs such as this one by Ilford (thanks for the link, Erik Gould!) to correct the development time if your temperatures are off. On Twitter, Dev Samaddar posted the following the other day: Why is development times always listed for 68ºF? Is the temp-time relationship linear? — Dev Samaddar (@dsamaddar) October 24, 2018 In this post, we will explore this topic further and try…

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The (al)chemist: formulary and chemistry books

For those that keep track of this blog somewhat regularly will not be surprised when I tell you that I am technically inclined. I have an interest in the chemistry of analog photography and recently purchased a few books on the topic. While I am reading them one by one, I am also writing reviews so you know which ones to get yourself. In this post, I will maintain a list of resources for you to consult and I provide mini-reviews of each. You will find links to the full reviews in the descriptions. This post will be a rolling release,…

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Determining the effective speed and development time

When you shoot film you have to be an artist and a technician at the same time. Before you open the shutter there are composition, creative use of contrasts and colours, and trickery with lights to be concerned with. After that come the concerns about aperture, shutter speed and film reciprocity behaviour. And then, in the end, there is film development. What developer do you use? At what dilution? And then, for how long do I leave it in? Should I agitate or not? If so, how often? In this article, I will be taking you away from the manuals…

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Processing 4×5 one sheet at a time

As soon as you start testing film, you quickly find out that using conventional small tank development is very wasteful. I currently use a Patterson tank with a MOD54 insert that allows me to process up to six sheets at a time. Unfortunately, this requires 1 L of chemistry for each of the three baths for the films to be completely covered. If I am to use this, I will end using an entire bottles of developer and fixer on just one film test. With this in mind I started looking for alternative methods for processing single sheets at lower…

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The developer decomposed – Part 1: Developing agents

You only need to open up a search engine and look for any film-developer combination, to find that there are as many preferences for specific combinations as there are people using them. Some prefer a pronounced grain and harsh contrast, while others want smooth gradation and tonality combined with minimal grain. Some may get away with a ‘thin’ negative, while others need considerable density for their further processing. But what is it that makes all these developers give different results, while the basic principles are the same? In this three part series on developers, I will cover the principles of…

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Travelling with film: the field test

Dressed in uniform, wearing latex gloves and with a never smiling face, the security officer at the airport tells you to take off your shoes, empty your pockets and put everything containing metal or electronics into a tray and put it on the conveyor belt to be x-rayed while you step through the bloody body scanner. If you are like me, this means that you have to open up that camera bag and put it in a tray. And this is where the worries that keep you up at night start. Should you ask for a hand check? The security officer…

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Reciprocity failure: the science

Lately I have been playing with the idea of trying some long exposures on film or direct-positive paper, but reciprocity law failure complicates shots that need much longer than a second of exposure. To explain why, answer the following question. When you close down the aperture by one stop, you can compensate for this by lengthening the exposure time by how much? … It probably didn’t take long to realize that you simply double the exposure time. However, chemical processes ongoing in the emulsion during exposure, makes the response deviate from the reciprocity law for very short or long(ish) exposures. In this article, I will introduce these processes…

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Method: storage of photographic film

Say, you just bought 10 rolls of film and plan to shoot them in the coming year. Or you have multiple printing papers that you use, some of which you use seldom. How do you store these properly and how do you keep them from developing undesired artifacts, such as a change in sensitivity (speed), contrast, color balance and fog level? Browsing the online photography fora will bring you a plethora of opinions and experiences with regard to the proper storage of unexposed photographic material. Some people claim that film that had been stored in a freezer for 28 years…

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Watching paint dry: the dry-down effect visualized

On page 44 of “The Photographer’s Master Printing Course” (ISBN 1-85732-407-2, 1995), Tim Rudman gives his readers some important advice that experienced printers often give to novices; to quote him: “Whether exposing for test strips or work prints, always base exposure calculations on dry prints. This is because prints, especially on fibre-based paper, darken as they dry – the so-called ‘dry down’ effect.” This is a piece of advice many inexperienced printers, including myself, more often than not choose to casually ignore. As Tim explains, the effect is considered to be most pronounced in fibre-based papers, which I currently do not use…

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