Pakolor Semi-Automatic RollHead Printer

Extracted from the 1959 BJPA, pages 251-252)

PAKOLOR ROLLHEAD PRINTER (Pakolor Ltd., Church Road, Epsom, Surrey)
The Pakolor printer is a colour printer of the semi-automatic type to be used in conjunction with the Pakolor Grading machine (as opposed to the fully automatic machine which grades and prints). It is designed for the production of colour enprints on rolls of 3½in. paper, or 1 : 1 " contact " prints on 2½in. rolls, from standard roll-film size negatives. The printer contains four basic parts: the enlarger unit, the lamphouse and filter unit, the rollhead and transport unit, and the control unit.

The enlarger unit is of normal design with condenser, negative carrier and projection lens, and is mounted over the desk containing the paper and controls. The negative holder is of the glassless variety and is designed so that the exposure cycle automatically proceeds on pushing the holder into position after loading.

The filter and lamphouse unit is mounted over the enlarger and contains three additive filters in light alloy mounts, each filter being brought into position successively during the exposure cycle by means of solenoids.

The rollhead unit accommodates a roll of paper up to 165 feet in length together with a take-up spool and a paper advancing mechanism whose pull-down depends on the proportions of the negative for which it is set.

The control unit links the other units in addition to carrying the controls for altering the three exposures to control the density and colour balance of the final print. Its operation cycle is started when the negative carrier is pushed in. The pre-set exposures through each filter are given in turn, the changeover of the filter being interlocked with the appropriate control circuit. The three main colour controls operate electronic devices which adjust the duration of the particular exposure in accordance with readings obtained from the grading unit. A further set of controls which are less accessible is used to adjust the intensity of the light during each exposure. This second set of controls is used to correct variations in the printing paper characteristics. The separate corrections for negative and paper characteristics is an extremely valuable feature.

After the exposure cycle has been completed the control unit operates the film transport mechanism, moving the paper into position for the next exposure cycle.

Apart from loading and unloading the roll all printing operations are carried out in white light thereby overcoming one of the principal causes of discomfort in colour printing.

The operation of the machine is very rapid enabling about twelve prints per minute to be made. As soon as each filter exposure is complete-indicated by an appropriate coloured pilot lamp-the particular control can be moved to the setting for the next negative so that by the time the exposure cycle is complete the controls are all set to the positions for the next negative. The negative carrier is withdrawn, the negative changed, and on pushing home the drawer, the next cycle commences.

The printer is 40 in. long, 27½ in. wide and 50 in. high and weighs 175 lb.

This page last modified: 31st January 2008