I would like to build my own 8 x 10 enlarger. I would like to use the so called cold light. I notice that these cold lights are extremely expensive in larger sizes. What makes them so darn expensive. Is it possible to purchase the compo nents and make ones own cold light.
I don't see why not. Just get yourself a bunch a 12-inch fluorescent tubes, some opal glass, and make a box to hold everything together. Watch out for the heat generated, even though they are 'cold'.
I can't say why they are expensive, but I suppose they are hand- built, with proper calibrated and stabilised electronics, etc.
Ansel Adams built his own 8x10 enlarger from an old 11x14 view camera. My factory Omega cold light head literally consists of a round flourescent tube and a 4x5 square of white Lexan in a can.
"It's the way to educate your eyes. Stare. Pry, listen, eavesdrop. Die knowing something. You are not here long." - Walker Evans
I have read the two answers to my question. First, I do not think that the tubes are plain old flouresent tubes. If anyone knows where to get the correct tubes please let me know. And secondly, does anyone know what is required to "stabilize" these tubes. Why I ask is because it just doesn't seem logical to me that a light source consisting of a few tubes inside a couple of dollars worth of sheet metal should cost over $1000.00. Thank you. kevin
hi actually, i would say that's pretty much the case for everything we buy. i mean, what's in a camera - a pair of plates and a bellows and a piece of circular aluminium for a monorail. what we pay the larger amount for is that somebody took the trouble of making the initial mistakes and ironing them out and the fact that we are uninclined to take the trouble/lack the knowledge etc. you also, of course, pay for precision engineering, a 'guarantee' that stuff is aligned etc. if you like tinkering, there is no reason you can't make it. you could call aristo re the light. re the stabilization, the usual stabilizers will cause some problems. i've had noticeably flickering lights when i used a stabilizer meant for condenser sources - the flickering disappeared when i removed the stabilizer. i'm afraid i didn't understand the explanation - something about voltage and cycles per second. i believe there are stabilizers meant for cold lights. and ansel adams ('the print') mentions a (horrowitz?) stabilizer which actually monitors the light output and keeps that constant. hoep this helps. dj
forgot to add. another reason 8X10 enlargers cost more than 4X5 is that there is a much more limited market for them and so the economies of scale are just not there.
Kevin, I'm interested also in homemaking a cold light box for an old 5x7 enlarger; I have found a lot of different fluorescent tubes, in different sizes, all of the same name brand, Philips, G. Electric or Osram. I have seen one really cold (cold color, blue) only available in big tubes, another cold also but less than the first one (blue- green) and the third have more yellow, is a bit hot (green-yellow). The rest of the tubes are hotter, from yellow to red; I understand that the photographic papers are sensibles specially to blue light, the coldest the color of the light, the shortest the time of exposure. In addition, I think we need a instant starting device for the tubes, and a stabilizer could help also. It's difficult or impossible to find in my city (Madrid, Spain)light sources like the Aristo or Zone VI, I'm obliged to build my own difusion head. I'm not an expert, the opinion of a tecnician will be great. If you want to share some ideas, don't doubt to send me an e-mail.
The actual cold light and associated circuitry are really not that expensive(I purchased an 8x10 from Aristo about five years ago for $250) however the necessary adaptation to a specific enlarger would drive it up some... the higher cost for variable contrast applications is the result of the necessary "balancing" circuitry needed to control the tube output(s). These are not the simple flourescent tubes found in conventional applications and there are a number of different "compounds" available for different light temperature outputs. (I have the W5500 which ostensibly provides a roughly "daylight equivalent" and if I had it to do all over again I would probably opt for the W3100 simply to more nearly approximate the color temperature of a tungsten-source diffused lamp). In essence you have the housing, the tube (or for VC, tubes), transformer, a thermal switch which helps maintain output stability by regulation of the lamphouse temperature and a diffusor (similar to opal-glass). Admittedly, VC by means of a "dial-in" would be convenient but for the difference in price between a single and multiple-tube sources, I'll stick with the single. Unless you are in a situation where voltage fluctuates fairly severely, the variable output device sold by Aristo (ca. $80 if memory serves me correctly) which is a simple "autotransformer" or VARIAC should be sufficient to achieve an order of reliability greater than most of us require. One of the features of this, compared to flourescent tubes, is that you really do need "instant-on" capability because of your timer circuit - something not easily (if at all) attainable with flourescent tubes. This "inductive load" (the transformer) is the reason that some timers cannot handle the transient caused by initializing the circuit - these are generally the solid-state type timers and even they can be adapted by means of a relay. Hope this helps. JE
You can find answers to most of your questions at the manufacturer's own web site:
http://www.aristogrid.com
Joel, that's the response I need. Thanks a lot. Only one more question; Why could be desirable a lower temperature lihgt source? Could it be better for enlarging in VC papers?
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