I just borrow a Paterson Cds enlarging computer, but don't know how it works! I have to start printing tomorrow. On the meter there is dial in Seconds(2.5 to 110), and dial of Paper speed(From A to M). There is a small indicating lamp on the meter. I noticed the lamp will be on where there is light, and turns dim when the combined dial is turn clockwise in some degree. The question is: how come the paper speed is in Alpabethical and not numeric? What is the basic idea of this?

-- Kevin On Man Lee (kevin.o.m.lee@bc.sympatico.ca), January 02, 1998

Answers

As no-one else has answered, I'll give it a whirl, although I've never used one of these.

The paper speed -- "A" to "M" -- needs setting for your particular paper. Once you've set it for your favourite paper, it shouldn't need changing, except possibly for a small adjustment from one paper batch to the next.

Once the paper speed is set for your paper, put the meter's window under the enlarger, with a mid-gray part of the negative shining on the window. Stop down to the desired aperture. Twiddle the meter until the light just goes off (or on). Read off the exposure in seconds. And there you go.

To calibrate the meter for your paper, first make a test strip to determine the "best" exposure. Now follow the above procedure, but twiddle the paper speed dial until the light just goes off (or on) at the desired exposure.

You can vary this procedure to do "proper" metering, looking at the negative shadows (ie the darkest portion), or even measure the contrast of the negative to give you an idea of what paper grade you need. However, I always do test strips, so I don't feel qualified to advise you on this.

-- Alan Gibson (gibson.al@mail.dec.com), January 04, 1998.