As a rank and somewhat elderly beginner in b&w printing, I can't quiote get the hang of using variable filters with my ilford multigrade paper. Is there some rule (or rules) of thumb I can follow. When I experiment with changing filters, either I get no discernible difference or too much difference in contrast, for instance. I'm sure it's a matter of experience, and getting the `feel' of the capacities of different filters. But maybe I'm just being too timid in increasing the increments. Thanks for any helpful thoughts on this.

-- David Gelman (GelmanEd@aol.com), March 07, 1998

Answers

Generally you should see a gradual difference as you increase by 1/2 steps with these filters but sooner or later you hit a point where it seems to change rapidly. One of the first things I did when starting to use these filters was to pick one negative which had a wide tonal range and good exposure and then to print it with every filter on 1/4 sheets of paper. It gave me a good sense of the range available. Also these filters slowly lose their contrast on exposure to light so if you are using old filters the most used ones may be lower contrast. That is why it is best to compose and focus without the filters in place. Apparently the newest ones are a little more permanent.

-- Andy Laycock (agl@intergate.bc.ca), March 07, 1998.

Variable contrast filters

I generally proof print all my images on 10 X 8 at a standard grade. Although lenses also affect contrast (I use Minolta which are contrasty, where as Nikon lenses will be less contrasty) as a general rule start at 2. From there it is a matter of experience, because contrast varies between chemicals and there temperature, film, exposure, lenses, type of enlarger, paper etc. so no rules can be applied.

-- Neal Garman (neal@ngarman.demon.co.uk), March 08, 1998.

One other area to be concerned with is your consistancy, particularly you developmnet times. Establish a standard print development time. For RC I would recommend that you make 4 identical prints using a 2 filter, making sure to have a good area of deep black in the image. Process the prints individually, 1 for 15 seconds, 1 for 30 seconds, 1 for 45 seconds and 1 for 60 seconds. Now look at the blacks and see which one takes the least development time to give you the maximum black. This is the minimum time that you should develop your prints for.

Under development will affect the contrast of a print, but I think you will see that over development only makes the print look darker.

For fiber based papers I would recommend 1 minute, 1 1/2 minutes, 2 minutes, 2 1/2 minutes and 3 minutes, but feel free to extend the times to get a feel for the changes that take place with extended development times.

Whatever you chose as a standard time, don't vary from it, always develope for that amount of time. By doing so you remove a variable, and establish a reference point. You can change any other factor, printing time or contrast grade, but your development time stays the same.

This, in combination with the other suggestions, should help get you on the right track.

-- Marv Thompson (mthompson@clinton.net), March 08, 1998.