Variable Contrast Light Head or VC Paper ?

[Richard Rees]

I have a Zone vi variable contrast light head on a Beseler 4x5, I can not get a good print from it, prints seem "muddy" for lack of better terms. I have tried difference negs, diff developers, the results bacisly the same. With same neg I can get a good print on my other enlarger which just has a cold light and using graded paper. Is it the Light head the VC paper or just me. Any help or suggestions, Thanks Richard

[Sevo]

Well, first of all: You do own and use a VC safe darkroom light, right?

Ages ago, there were quite distinct differences in colour response between the Kodak and Ilford VC papers - Ilford filter kits and heads were close to useless on Kodak. I don't know how your head acts on current paper - it might be considerably wrong. Or the mixing box or condenser could be set up the wrong way. Or you need a different developer.

The cheapest way to find out, without spending money on a filter kit, would be to do a few test prints on graded paper - if the enlarger is ok, these will be fine, and you have a head/paper mismatch or a issue with your paper. To exclude the latter, try with sheet filters, on both enlargers.

Sevo

[Keith Pitman]

What settings are you using for each of the different grades?

[Mark Sawyer]

I'd consider changing the VC filters in the enlarger head. Those filters don't last forever...

[Jon Shiu]

I suggest a fitting the condenser head, if you have one for your enlarger. Gives more sparkle to the highlights, at least with the Ilford MGIV or Warmtone papers.

Jon

[Gem Singer]

Richard,

Your darkroom safelight might be causing the problem.

Try turning the safelight off and printing in total darkness.

Set the hard, soft, and brightness controls of your VC cold light to max. Make a test strip. Then a test print.

If the print still shows signs of fogging, your VC paper is fogged or there is a light leak in your darkroom.

[John Bowen]

Next time you are in the darkroom, tear a sheet of VC paper in half. Put 1 half directly in the fix and put the other half (unexposed) into your normal developer, stop and fix. Once finished turn on the lights and compare the two sheets. I'll bet your VC paper is fogged.

Now add some 2% solution of Benzetriozole to your developer (perhaps 30ml/liter) and repeat the test. If the fog vanishes start printing. If the fog persists, add another 30ml of 2% BZ and repeat until the fog clears. Make notes.

[photographs42]

Is this the Head with one Blue and one green light tube? If so, are both tubes working? Also, how are they controlled?
Jerome

[Richard Rees]

I have a Thomas Duplex super safelite, with the doors shut all the way. Don't think the paper is fogged, has done this from several boxes/ sizes of paper. Have tried all diff setting on controller. Thanks, will recheck, paper and safelite. Richard

[David E. Rose]

I have the same head. It has always had the issue that one tube has much more output than the other, making the contrast settings on the controller inaccurate. Try split printing with only one tube turned on at a time, controlling contrast via length of exposure with each tube.

[Keith Pitman]

Generally, identical settings for each light should give you approximately grade 2. Increasing the hard/blue light will increase contrast, and increasing the soft/green light will decrease contrast. You need a consistent procedure to use the Zone VI head, not just random settings. Check this post for my tested settings for Multigrade:

http://www.apug.org/forums/forum41/71414-question-observations-using-zone-vi-vc-head-2.html

Also, try turning off one light and increasing the other to see if the light gets brighter; then test the other light. You might find one of the lights (more likely the hard from your description) is not functioning--could be the rheostat.

I may have a copy of Zone VI's instructions. PM your email address and I'll scan it and send it to you. It will be next weekend as I'm out of town until then.

Good luck.

[ic-racer]

A step wedge will answer the question. Just a guess, you have a $200 exposure meter but no step wedge, right? :) :)

[Brian Ellis]

Considering te fact that you're getting good prints in the same darkroom with another enlarger and with various different papers it's unlikely that you have a safelight or paper problem. And of course there's no point in buying a new filter kit because your head doesn't use filters. So I'd first look at the VC head itself. Put a sheet of plain white paper in your easel and set the head to the lowest contrast - which was .1 or .5 on my Aristo 4500 VCL head. The color of the light should be totally green. Now while looking at the paper turn the controls so that you gradually add more and more blue light. You should see the color of the light on the paper gradually get less green and more bluish, until you end up at the highest contrast (5.1 on my Aristo 4500 VCL), at which point the color of the light should be all blue.

If that isn't what happens then the light isn't working correctly. If it is what happens then the next thing I'd do is turn all the lights out in the darkroom, put a cap on the enlarger lens, wait about ten minutes, then turn the enlarger light on and look carefully all around the enlarger chassis and especially around the lens board. If you see any light leaking anywhere fix it with black electrical tape or whatever else you have that will plug up the leaks. It seems unlikely that your enlarger is leaking light badly enough to fog the paper but you never know and IMHO it's just good darkroom practice anyhow to fix any light leaks from the enlarger.

If those things don't work then do a serious safelight/paper test (not the one described here but the one described on the Kodak web site or in Ansel Adams' book "The Print" if you have that book).

If none of those things show the source of the problem then I don't know what it is.