aristo cold light head

[Andrew O'Neill]

Paul, the VCL4500 has a round portal...at least mine does. It's very very even illumination as long as placed very close to negative. My aristo 1212 with V54 tube is extremely even.

[Brian Ellis]

"During a workshop years ago John Sexton advised us that the standard diffuser for these coldlights is too thin."

Are you sure John was talking about the VCL4500? I've taken all three of the darkroom workshops he used to offer plus a fourth non-darkroom workshop and I don't remember hearing anything like that with respect to the VCL4500. Not that my memory's all that great but since I was using the VCL4500 at the time of all these workshops I think I would remember (and would have acted on it since I have the highest respect for John's knowledge - and as an aside, his workshops are the greatest IMHO, anyone who hasn't taken one is missing out on a terrific experience). John doesn't use the VCL4500, at least he didn't when I was taking his workshops 5-10 years ago. At that time he was using a Saunders with its VC head and another enlarger, the brand of which escapes me.

[paulr]

"Paul, the VCL4500 has a round portal"

what's the configuration of the tubes in the unit? i might have it confused with something else, based on its rectangular top. i was thinking of a head where the tubes where in a rectangular grid that's larger than the circular part.

in general i think one of the problems is with enlarger design. it always drove me crazy that these enlargers allow room for a light source that barely covers the negative. the most uneven light source i ever used was the omega dichroic color heads on the enlargers at my college and at the commercial lab where i worked. most of the problem was due to the barely adequate coverage. another quarter inch would make a difference.

[phil sweeney]

For uneven illumination in general I made a mask using Alan Ross's methods, using OHP trans material after scanning a print of the uneveness. Works perfectly. Might be easier than the lith thing.

Strange that half the print needs burned in.

[Hans Berkhout]

Brian I'm sorry for the confusion I may have created: John was discussing the Zone VI (or Aristo D2) cold light source. The VCL4500 didn't exist yet, at that time!

[Chuck_1686]

Have you done some obvious troubleshooting. Like rotating the head to make sure the problem rotates along with the head. Maybe something else is the cause.

[paulr]

"Might be easier than the lith thing."

yeah, that sounds a lot easier, actually. didn't cross my mind ... i made my mask years before all this digital stuff landed on my desktop.

[Gary L. Quay]

I may be reviving a dead thread, but here goes: I'm thinking about buying an Aristo cold light head for my D5 enlarger. It's the really tall version, so I'd like to be able to print up to 20 x 24. I saw a few posts sayng that 11 x 14 was the largest possible. Does anyone have experience to the contrary? Would I be better off with a simple diffuser or a color head? I like the idea of a cold light head because I've heard that they hide scratches to an extent.

[Eric Brody]

I cannot comment about the issues regarding maximal print size with your D5, but the dust reduction effect, if any, is common to any diffusion head, regardless of the light source. The theoretical basis is that condenser light is more collimated, closer to a point source and thus less kind to scratches and dust on a negative. Typically condenser heads require a negative with a bit less contrast, diffusion heads require a bit more, but otherwise except for issues of heat, are more similar than different. I have not printed with a condenser since I was a teenager, a really long time ago, but have spent considerable time with a Beseler diffusion colorhead, a standard Aristo cold light, and also with a Zone VI VC cold light head and all are easy to use and give great results once you spend some time and learn how to use them.

Eric

[Gary L. Quay]

Thanks Eric.

To anyone else who may know... Is the light fall-off of cold light heads too great for making larger prints?

Thanks!