BANISH THOSE TEST-STRIP BLUES
Notes by Roger Bamett (Former member of Bon-Accord Camera Club)

(From the Scottish Photographic Federation magazine. December 1999)

Wouldn't it be great to be able to cut down on those tiresome and time-consuming killjoys of the Darkroom enthusiast, the dreaded Test Strips? Well, follow the tips in this article and these little beggars could become just a fading memory! This method assumes that every film processed brings forth
a contact sheet.

If not, why not? Contacts are very useful, not only for presenting the images in a positive form for better visual evaluation, but also as an exposure guide when doing enlargements and determining the exposures of enlargements at various sizes.

Ok, so firstly a contact sheet is printed. When doing this, the head of the enlarger should be set to approximately 50 cms up the column scale. I say "approximately" because various makes of enlarger differ in how the head is aligned with the calibrations on the column.

The light thrown by the negative carrier should just cover the contact printer. This rectangle of light must be focussed, i.e. the edges of the carrier should look 'sharp' on the baseboard. When ascertaining the correct exposure for the contact sheet, use a standard time of 12 seconds and alter the lens aperture for the 'fine tuning' of the final exposure. This 12-sec standard is important, because all subsequent blow-ups are based on this exposure as their starting-point. It's a sound idea to write on every contact sheet the exposure it received, so at a later date this can be quickly
referred to.

Right, so now we have a contact sheet with a known exposure. To print enlargements with a minimum of fuss, simply consult the table below.

These calculations are based upon the size of the area of the projected image, rather than the height of the enlarger head, for the same reason as mentioned earlier For exposures to be accurate, all procedures must be consistent, e.g. processing temperatures must be kept accurate and stable. An exposure timer is highly recommended.

So if the contact sheet -------------------------------------- = 12 seconds on F5.6, then
10" x 8" ---------------------------------------------------------- = 9 seconds on f5.6
10" x 6" (full frame) ------------------------------------------- = 6 seconds on f5.6
8" x 5" = 9 seconds on f8 5" x 4" -------------------------- = 9 seconds on f11
5" x 2 1/2 -------------------------------------------------------- = 6 seconds on f11