are Illford VC filters OK for Kodak VC paper?

[FrankToronto]

I normally use Illford VC paper and Illford VC filters. My darkroom work is done in a camera club darkroom (sadly few people use it).

There is some "hand me down" paper in the darkroom. Don't know the actual Kodak variety it is, simply know it is Kodak because you can read the Kodak name on the back of the paper.

When tying to use Illford VC filters with this unknown kodak paper, which seems relatively fresh because it is not fogged like a lot of the left behind papers, I get totally different contrast results from what I would expect (i.e. normally low number filter for less contrast, high number filter for more contrast).

This suggest to me that Kodak has a different filter scheme and that you can't use Illford filters in the same way. It appears that I am getting more contrast with the lower numbers and lighter contrast with the higher numbers.

So my two questions are:

1. can you still use the Illford filters and what conversion factors should I use.
2. how are Kodak filters different?

thanks for your help

Frank

[Steve Smith]

Should be similar but won't be the same.

Just work on the principle of needing more or less contrast rather than thinking in actual grades.


Steve.

[Mike O'Pray]

Originally Posted by FrankToronto

I get totally different contrast results from what I would expect (i.e. normally low number filter for less contrast, high number filter for more contrast).

This suggest to me that Kodak has a different filter scheme and that you can't use Illford filters in the same way. It appears that I am getting more contrast with the lower numbers and lighter contrast with the higher numbers.

Frank

Frank, as Steve has said just use the Ilford filter that seems to give you what you deem the print needs in terms of contrast. Do you have an enlarger analyser? Some of these give suggested grades by using a probe and measuring the highest zone where there is some texture and the lowest zone where there is some texture. This is done on a built in algorithm which calculates the difference in densities and then arrives at an appropriate grade. I mention this because the machine's suggested grade is usually close to what you'd choose yourself and it would be interesting to see by how much the suggested grade and your chosen grade differ using the "correct" Ilford filter.

I cannot explain why a lower number ilford filter appears to give a greater contrast than a higher number unless the higher Ilford filters are worn to such an extent that in effect they are useless and thus the lower grade filter which are OK are therefore delivering some contrast as opposed to the higher ones giving almost no contrast at all?

Are these enlargers with dichroic heads and filter drawers? If so try using the dichroic head for filtration instead, using the Ilford single or dual filtration method and see if the higher units on the head( i.e. more Y = higher grades) actually give higher grades, They should and if they do then I'd suspect that the Ilford filters are "shot"

Interesting academic puzzle is emerging here which we might be able to solve with your help

Mike

[Mike O'Pray]

P.S. I don't suppose that this hand-me-down paper is not VC paper i.e. single graded? Mind you if that were the case then the filters should make no difference either way except to increase exposure

It's puzzling

Mike

[FrankToronto]

thanks for the responses
back to the darkroom to try some more experimenting….