I just set up my old darkroom (15 years old). I have a old beseler 23c (series II) enlarger. I want to purchase a filter kit. I appears to have a slot for a 5-1/2 X 5-1/2 filter above the lens. Should I purchase a filter kit for this slot or is it better to have a filter kit which is mounted below the lens? Is one brand better than others (e.g., Kodak, Ilford...)?

Thank you in advance for your response.

-- daniel zorilla (dvzorilla@juno.com), June 04, 2000

Answers

Above the lens filters are better. Less dust problems and the image is not degraded as it would be with an under lens filter. As far as which brand is best? I have a set of Kodak filters for Kodak paper and a set of Ilford filters for Ilford.

-- Robert Orofino (rorofino@iopener.net), June 04, 2000.

The statement that above-the-lens filter are better is often repeated, although it was never fully substantiated. If I recall this correctly, Ctein has tested below-the-lens filters, and wrote that he was surprised NOT to have found any adverse effect. Dust on below-the-lens filters is not as much of a problem as it would be on the negative itself as the filters are well out of the plane of focus.

-- Thomas Wollstein (thomas_wollstein@web.de), June 05, 2000.

Below the lens filters are OK if they are kept in imaculate condition. I myself prefer to have as little as possible between the negative and paper, so I use a dichroic enlarger. People fret about putting a UV filter on a camera lens and it should be the same with an enlarger lens. You'll have to be really anal with plastic below the lens filters. They're easily scratched.

-- Tim Brown (brownt@ase.com), June 05, 2000.

strictly and anally speaking Tim.... Ilford makes a lovely set of "below" filters in black plastic frames(with teeny handles and a lens mounted holder) that by their nature of design and the design of the storage box last a very long time.... longer than any other polyfilters I've ever owned...

I think if I buy another set I'll get those thick, dishwasher-safe unbreakable ones that look like cokin system jobs... anyone know the mfg?

ya see, I'm a bit clumsy....

-- Trib (linhof6@hotmail.com), June 05, 2000.

The below the lens filters is the easiest option, and if you use the Kodak and Ilford gelatin filters designed for this approach, you will have no degradation to the image. I checked the resolution with no filter and with a Kodak gelatin filter, and could see no degradation whatsoever of the finest resolution lines of my Four Seasons test positive. A swing out holder allows one to add a filter without vibrating the enlarger, and heat affects (fading)on above-the- negative filters is not a problem with below-the-lens filters. Above the lens filters are delicate, and must be handled with the fingers. Below the lens filters are in a mount with a nice little handle.

I would not use thicker plastic filters because I believe they would have a negative effect on optical transmission.

-- Eilert Anders (Eilert@dav.com), June 05, 2000.

I prefer the above the lens type primarily because there is less dust. Ideally I would prefer a dichroic head or dedicated vc head but there isn't one available for my Omega B-8.Is there?

-- Robert Orofino (rorofino@iopener.net), June 05, 2000.

I had the same question about filter brands a while back and decided to test it.

My unscientific approach:

I bought a Ilford filter set to add to my Kodak filter set, and paper from each brand. I printed the same neg to each paper unfiltered, Polymax Fine-art fiber and Mulitgrade IV fiber, adjusting exposure to achieve the same densities in key areas of the print. (Critical note: I didn't use a densotomiter, just my eye for the evaluation). Then I printed on Kodak paper using the #2, #2.5, #3 filters from each set. Then I did the same with the Ilford paper. Processed all the same way.

My conclusions:

The filters definitiely differ in the way they affect the image. The characteristics of the filters, however, seemed consistent on both brands of papers. In other words, the Ilford filters seemed to have the same degree of alteration on each base image, as did the Kodak. In a nut shell, my tests didn't lead me to think that there's a better filter set. I think it's more important to find a paper you like most, which my testing did, and use that filter set.

Caveats:

I think it's good to match brands between filters and paper, but I keep my tests pinned to the wall to remind me of the possiblities of mixing a matching. Who cares how you got there all that matters is the image.

Also, I used my eye to match densities, and comparing an Ilford #2 to a Kodak #2 is not a apples to apples comparison, so the techno junkies out there will shoot all kinds of holes in this test.

For what it's worth, in reading the spec sheet of papers other than Kodak and Ilford, those that mention filtering seem to recommend Kodak filters.

I use a Omega B-8 with an above lens filter drawer and like it. I can maul the filters and not have to worry about finger prints or scratches. After a couple uses I ended up mounting the filters to homemade, posterboard "holders" to make them easier to handle--definitely worth the time. I learned on a 23c and below lens filters, and can't say I've noticed a difference in image quality when the filters were clean.

good luck

-- rick simpson (rsimpson@adobe.com), June 21, 2000.

The other idea is to NOT buy multigrade filters, but buy a set of color filters. That way you can mix and match to get the exact contrast range that you need, rather than being stuff with "grades".

The only downside is if you just use yellow and magenta alone, you will have to adjust the exposure time as you change filters, but you can do that through some minor calculation.

-- Terry Carraway (TCarraway@compuserve.com), June 22, 2000.