I've been working witn graded papers for years, but lately I've been printing more and more with variable contrast papers. I have an older Zone VI cold light head, with voltage stabilizer, and I know that the contrast grades don't correspond to the VC printing filters without additional filtering of the light. I've read that a cc40 yellow will solve the problem. I've also considered purchasing the newer Aristo cold light head, which I believe is the Model 5400. Would I gain anything with the newer Aristo compared to the older Zone VI with cc40 filtration?

Thanks in advance for your feedback,

Frank Burtnett

-- Frank C. Burtnett (confra@earthlink.net), January 25, 2002

Answers

Dear Frank, The Aristo VC4500 will revolutionize your printing on VC papers. Look at Ted Kaufman's thread entiltled " split Printing" on this forum. However look quickly because it is about to become out dated.

-- John Elder (celder2162@aol.com), January 26, 2002.

The yellow filter will accomplish nothing and will lengthen exposures. Simply replace the tube in your Zone VI head with an Aristo V54 tube. It'll provide very even contrast spacing.

-- Sal Santamaura (santamaura@earthlink.net), January 26, 2002.

What I like most about the VCL 4500 is the ability to simply dial in the contrast setting I want. This makes split printing and dodging and or burning at different grades a breeze. My only regret is that I did not get this system much sooner.

-- Jim Billups (jim@jimbillups.com), January 26, 2002.

No Sal, the yellow filter does lower the amount of blue light that gets to the paper. For the longest time I had a lot of trouble lowering the contrast with my Zone VI VC head until I got me a B+W 40 cc filter. Since then I have been able to get very nice contrast variation. Besides is cheaper to buy the filter than to change the entire blue tube.

-- Jorge Gasteazoro (jorgegm58@prodigy.net.mx), January 26, 2002.

A yellow filter will do nothing to address the shortcoming described in Frank's question, namely print contrast bearing no relationship to filter numbers. Yellow does lower contrast and, if 40cc is more yellow than the softest numbered filter in one's Polycontrast/Multigrade filter set, it will result in less contrast than that filter would. However, Frank mentioned nothing about an inability to achieve low contrast. Compared to the VCL-4500, a V-54 tube is a much less expensive way to circumvent the phenomenon Frank is experiencing.

-- Sal Santamaura (santamaura@earthlink.net), January 28, 2002.

Sal & Jorge:

You'd have to know the spectral response of the tube in the current Zone VI head to know whether or not a yellow filter would help. Zone VI had several different heads, of different manufacture, and at one time offered different tubes.

-- Charlie Strack (charlie_strack@sti.com), January 28, 2002.

Charlie: "...to know whether or not a yellow filter would help." Help what, contrast spacing or lower limit of achievable contrast? Don't all the non-VC Zone VI heads use tubes with single spectrum line (essentially blue) output? Doesn't this mean that no filtration can be added which would even out contrast spacing?

-- Sal Santamaura (santamaura@earthlink.net), January 28, 2002.

Actually Sal I belive the use of the yellow filter is to lower the amount of blue light which is the one for HIGH contrast.....thus, if you are getting high contrast and cannot lower it because the light is too blue, then you add a yellow filter, which is the case with me. I could not lower the contrast and as soon as I used a yellow filter all the problems went away.

Charlie:

I agree with you ideally you would have the spectral information on the light to choose the right amount of color to block, but yellow does block blue and the problem is too block it at the high end of the visible spectra which is the one affecting the prints. A yellow CC40 works just fine for this.

-- Jorge Gasteazoro (jorgegm58@prodigy.net.mx), January 28, 2002.

Jorge, in your first post you said you're using a yellow filter on your Zone VI *VC* head. Such a head includes both blue and green tubes. So your light source has spectral output in the yellow region. Using a yellow filter on that light source, it is reasonable to expect that you might be able to achieve lower contrast than even shutting off the blue tube completely, since the green tube's spectral output is not totally free of a blue component.

Frank is using a standard (non-VC) Zone VI head. That tube's output is essentially blue. Adding a yellow filter will likely have the effect of lengthening exposure, and *perhaps* lowering contrast - - if there's less yellow in his lowest-numbered printing filter *and* the tube has more than slight non-blue output - - but will not address the question Frank asked about. Contrast spacing will remain uneven and unrelated to filter numbers.

-- Sal Santamaura (santamaura@earthlink.net), January 28, 2002.

Ok, Sal I guess we will agree to disagree. I do agree that contrast sapcing will not be afected by adding the yellow filter. But the yellow filter might help to keep the contrast within the paper response. It seems to me that this is two question, one, will the yellow filter help in producing even spaced filter gardes? No, of course not!! will it help to keep the paper response within a desired range of contrast densities? Yes it will!!

-- Jorge Gasteazoro (jorgegm58@prodigy.net.mx), January 28, 2002.

Frank, if you can afford one, go for the VC4500....or the 2 tubed VC Zone VI ( I use the aristo)...or for that matter a dichro color head. If not, try the V54 tube....a cc40y works okay, but will drive up your exposure times....I use an older hi-int D2 aristo head at work, and just use the filters without the yellow filter at all...I did some step wedge tests to figure out what the approx "grades" were, if you can call them that...about half the filters will be useless, although you can split filter with the -1 and 5+ and usually do okay. If that doesn't work, I usually keep a couple of boxes of grade 1 paper on hand to cover the really contrasty stuff....you'll only have problems trying to tame contrast....in comparison, the 2 tubed heads (or a color head) are a dream to use....hope this helps.

-- DK Thompson (kthompson@moh.dcr.state.nc.us), January 29, 2002.

Sal & Jorge:

If you get an Aristo catalog, they show the spectral responses of their various tubes. Some simply don't have much green at all and a yellow filter will just slow down printing, and you just don't have enough green light to start with to get a moderate to low contrast.

Others have lots of blue, but a reasonable amount of green, and a yellow filter will help you use regular VC filters to get a broader contrast range, though not all the paper is capable of.

My understanding, and it certainly isn't full knowledge of the subject, is that these tubes don't produce single-wavelength light (like a sodium vapor light) but a broader spectrum (though still relatively narrow). The Aristo catalog clearly shows this. It may be that phosphors are blended to avoid a single color for the simple reason that it's easier to focus and compose with more than just blue light.

This is all based on the old tubes, not the new V54 tube (I think it is) which has green and blue producing phosphors in the same tube, where regular VC filters are usable directly.

So all I was saying is that neither of you is wrong, and neither is right. You don't know how to fix it until you know what you have. Or, sometimes a CC40 filter will do the trick and sometimes it won't.

In any case, if a VC head is affordable, that's fine. Just getting the V54 tube is much less expensive and will work, too.

-- Charlie Strack (charlie_strack@sti.com), January 29, 2002.