Paper Grade Management System for Enlargers
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The SPLITGRADE system, manufactured by Heiland Electronic GmbH, Wetzlar, Germany is an automated system for fitting the contrast grade of b/w paper to the contrast range of the negative, thereby producing prints with optimum highlight and shadow detail and a full range of tones. Comprising a microprocessor based controller and a motorised filter module, it can fine tune the contrast of variable contrast paper to within 0.1 of a grade. The filter module has two filters, yellow and magenta, and exposures are made through each filter in turn. The ratio of the two exposures controls the resulting contrast of the paper. The system is currently available customised for several popular enlargers, with more to come. For existing users, the latest firmware is available for download here.
Heiland has recently introduced a range of LED cold light sources which interface directly to the Splitgrade system and which can be adapted to many different enlargers from the Leitz V35 through 6x9, 5x4, 7x5 to 10x8.
The "Comfort" control interface adds a new level of convenience to the operation of the system and can be added to existing controllers as an option.
For convenience, we have summarised the differences between this system and our Exposure Meters here.
The Splitgrade Philosophy
Several influences characterise a black and white photograph. Before taking a shot of the subject the photographer recognises the subject contrast and determines the exposure and development of the film in order to reproduce the subject. The resulting negative will have a contrast range ideally in the region of 1.0 to 1.1 logD but in practice this will vary somewhat especially if, for example, a variety of different subjects are shot on one roll of 35mm film. To make a print from each negative the contrast range of the paper should be chosen to match that of the negative, and variable contrast paper offers an ideal solution to this.
If you are working with a conventional grade control system there are a number of factors to consider:
- Sets of contrast filters allow steps of only half a grade, and they are also not optimised for the variety of light sources that are used in enlargers. Also, the actual contrast produced by any given filter will be dependent on the characteristics of the paper in use.
- When using infinite grade systems (colour or VC heads) the major disadvantage is that the range of possible grades is not linear. In other words, a given adjustment may result in a different change in paper contrast depending on the starting point.
- Most systems have no accurate exposure compensation when changing grade. The "consistent exposure across grades 00 to 3.5, and double the exposure at grades 4 and 5" is a myth; it only applies to a particular print density.
- The photographer has to work out for himself the optimum settings for his combination of film, enlarger and paper.
All these problems have led to the development of the Splitgrade system. Read the user manual (306K pdf)
Splitgrade simplifies the steps to make a print
All you have to do is
- Load the negative into the enlarger, select the film and paper type, compose and focus the image.
- After focussing, select the lens aperture you wish to use.
- Using the light-sensing probe, explore the baseboard image ensuring that the lightest and darkest parts are measured. The controller can now calculate the best contrast grade and exposure time for this particular negative.
- Postion the paper in the easel and press the "Print" button.
The result is a fine print retaining all the detail in the negative. At any time, you may change the exposure and grade settings manually to fine tune the result, or to cater for high or low key subjects.
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