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Method: Testing old paper

Two weeks ago I was given an old box of Agfa Brovira-Speed BN312PE, grade 3 paper. It has been sitting in a cupboard on an attic for at least 15 years under less than ideal conditions. To determine if the paper is still of any use, I tested it for fogging and checked how it responded to anti-fogging measures. In this Method Section, I will briefly explain how I went about testing this paper and my conclusions. If you have any tips or tricks, drop me a line! I’d be happy to hear!

How to test for fogging?

A fog test is very simple to conduct and the procedure is explained by Tom Johnston on youtube. To test a sheet for fogging one takes an unexposed sheet of paper and lets it pass through the three baths of developer, stop and fixer as one normally would. Another sheet of paper only goes in the fixer bath for the regular time to get rid of all the unexposed silver salts that are in the paper. This last sheet provides a sheet of pure paper base white. If the fully developed sheet is darker than the undeveloped sheet, the paper is fogged. To exclude any other effects such as safelight fogging, this test has to be conducted in total darkness, so if you are not used to working under those conditions first familiarize yourself with your trays and their locations, before you start.

Potassium bromide (KBr) to the rescue: anti-fogging

As Tom already suggests in his video, the use of potassium bromide (KBr) can be used to reduce or inhibit fogging. In addition Steve Anchell explains on page 74 in his book “The Darkroom Cookbook” (ISBN 978-0240810553, 2008) that a 10% KBr-solution will give clearer highlights and can produce warmer tones on the print.

To make 500 ml of 10% KBr-solution add 50.0 g of KBr powder to 400 ml of purified water to make 400.0 ml of solution. Use a (glass) stirring stick to mix until all powder is dissolved. Continue by topping it up to 500.0 ml and store it in an appropriate container, such as a pharmacy bottle. The equipment you need is shown in Figure 1. You may need a scale to make sure you have the right amount of KBr powder. Once filled label the bottle with “10% KBr” and the date of production.

Equipment needed to make a 10% solution of potassium bromide (KBr): high purity KBr, deminiralized water, measuring cup, funnel, stirring stick, pharmacy bottle and gloves.
Figure 1: Equipment needed to make a 10% solution of potassium bromide (KBr): high purity KBr, deminiralized water, measuring cup, funnel, stirring stick, pharmacy bottle and gloves.

In the Netherlands KBr can be sourced from several suppliers that also sell to individuals. For small quantities up to 500 g you can order from Bik-Bik pharmacy in Leiden. For larger quantities of 500 g to 5 kg you can consider Hinmeijer B.V. for your supplies. Purified water can be obtained from most home depots and pharmacies for less than a euro per liter.

My results

The plain test shows some rather severe fogging as can be seen in Figure 2. Starting in the top right we see the paper base white. This is obtained after just fixing the paper. Following the sheets clockwise, the next sheet shows the fogged paper. It has a clear grey cast after regular development in Ilford Multigrade developer at 1:9 dilution. To reduce the fogging I added first 20 ml of 10% KBr solution per liter of working solution of developer and later increased this to 40 ml/l. The fog is reduced, but not to the extent that paper base white is obtained. I did not push this further and consider the paper to be too fogged for normal use.

Figure 2: Clockwise, starting in the top right: paper base white, obtained after fixing; fogged paper, obtained after regular development in Ilford Multigrade 1:9; slight reduce in fogging after adding 20 ml of 10 KBr to 1 l of developer; and slightly more reduction in fog after adding 40 ml of 10% KBr to 1 l of developer.
Figure 2: Clockwise, starting in the top right: paper base white, obtained after fixing; fogged paper, obtained after regular development in Ilford Multigrade 1:9; slight reduction of fogging after adding 20 ml of 10 KBr to 1 l of developer; and slightly more reduction in fog after adding 40 ml of 10% KBr to 1 l of developer.

Some light fogging has the same effect as pre-flashing and could serve to rescue some very hard contrast images from the dump by lowering contrast. Every emulsion has some inertia and requires a certain minimal amount of light to obtain a perceivable change from paper base white to very light grey. Pre-flashing or fogging can be used to overcome this initial inertia.

Is fogged old paper good for anything?

You don’t have to throw it out. Even if it is considerably fogged and not useful for making prints in the darkroom, there are other applications for which the paper can be used. The more artsy people might for example consider making lumen prints (thank Bethe Fisher for the suggestion), photograms or use the sheets as paper negatives for a pinhole camera. Save it for one of those days when you cannot suppress the urge to just mess around and don’t have any expectations of the outcome. The results might very well be interesting!

Published in Methods Section