Black and White Photography Practice and Theory
Paper Processing Equipment
Introduction
The explanation of paper printing equipment will be on the same lines as the film process, ie by example. The first piece of equipment required is an enlarger. In its most basic form, an enlarger is a machine which shines a bright light through a negative and into a lens which focuses the image at the plane in which the paper is positioned. This is a diagram of a condenser enlarger:
Condenser Enlarger (BW)
The condenser
enlarger differs from the colour enlarger in the way that the light is delivered
to the negative. In short the colour head uses a box which scatters the light
which prior to entering the box is passed through filters. The light is then
passed to the negative and onto the lens for focusing. The condenser enlarger
is more complex and looks like the diagram below:
Condenser Enlarger Diagram
The condenser enlarger is traditionally used for black and white printing, but
can be used for colour with a set of slide in filters.
Controls on the Enlarger
I have a colour enlarger so will concentrate on the controls of my enlarger which is the Opemus 6.
Head Elevation is operated by a crank handle on the stem. The elevation is used for setting the magnification of the print. The biggest size of the print is dictated by the size of the stem and the focal length of the lens. As the largest sizes are approached, the design of the stem and the amount of overhang over the base board is important as part of the image will be projected onto the base of the stem. For very large prints, the head can be rotated for horizontal enlargement on a wall.
The negative carrier is where the negative is placed for enlargement. My carrier is a glass carrier, this has advantages and disadvantages, but if the carrier can be kept clean and free of dust, the glass gives support and helps the geometric integrity if the negative. The carrier can be adjusted for any size of film upto 6x6. Some manufacturers supply a negative carrier for each format of film.
The scatter box is polystyrene and is specific to the format, in my case either 35mm or 6x6. As nearly all of my film is 6x4.5 I am limited to the 6x6 box.
The focusing knob adjusts the distance between the lens and the negative. Depending on the type of lens used, the lens mount may have to be changed. With my setup, a 70mm lens is used on the 6x6 carrier and a 50mm lens is used for 35mm work. This enables the 35mm work to be enlarged to the full 12" x 16" of the base board.
The base board supports the machine and also forms a flat surface on which to mount the easel. In addition there are various adjustments which allow correction of parallels etc.
Timers are used to turn the enlarger on and off at set periods. This makes the production of test strips easy. This timer also has an exposure meter, which indicates paper grade and times. However I have found this unsatisfactory and have not used it for many months. The alternative to a timer is a metronome, which was how my initial prints were made.
Making an Enlargement
Firstly, the daylights must be turned off and the safelights turned on. Place the negative in the carrier after ensuring that it is clean and free from dust. Switch on the enlarger lamp and size the image on the easel by moving the head up and down the column. When the image is around the correct size, use the focus control to render the image sharp. There are devices called focus finders (pictured), which allow users to focus on the grain of the negative. These are very useful when the negative contains a lot of out of focus detail, prominent in macro photography.
At this point the grade and type of paper can be selected. Normal photographic paper is classified as grade 2, the grading system which currently runs from 00 to 5 is a method of controlling the contrast of the print. The lowest contrast or softest prints are made at grade 00 and the highest contrast prints or hardest prints are made at grade 5. The grade is selected for one of two reasons, either the contrast of the negative or artistic interpretation. If the negative is very high contrast, then a soft paper is needed to allow the tonal range to be rendered, if the negative is very low contrast then a hard paper is required to stretch the tonal range across the range of the paper.
Most photographic paper is now classed as multi-grade or variable contrast. This allows the photographer to change paper grade by use of filters which are either dialled into a colour head or used in a filter drawer on the enlarger. Pictured is a set of Ilford multi-grade filters. These can be used above the lens in drawer or below the lens on a holder. Above the lens is preferable as the problems of dust and dirt are eliminated.
Once the choice of paper grade has been made, the type of paper must be selected. The two choices are Resin Coated and Fibre Based. Resin coated papers are much easier to handle as the paper is essentially encapsulated in a plastic envelope and the emulsion stuck on the outside of the resin. This construction drastically reduces processing time, especially in the wash stage. A resin coated print takes about 4 minutes to wash in an archival washer, a fibre based print takes at least 30 minutes. Drying resin coated papers can be completed in a simple rack and does not require glazing. Resin coated papers are available in a variety of finishes including Gloss, Lustre, matt, stipple and so on. The paper can also be purchased in a range of sizes ranging from 4" x 5" up to 20" x 24"
Fibre based papers are the traditional style of paper, processing takes longer, more chemistry is wasted and the equipment to handle it is more costly. However it gives a far better result than the resin coated. Speciality papers are generally fibre based and fibre based papers react much better to toning and other special effects.
Once the image has been set up and the lens has been stopped down to about half of its maximum aperture, the test strip can be made.