Condenser vs. Cold-Light/ 8x10 Horizontal Enlarger

[nick rowan]

I would like to convert an 8x10 camera to an 8x10 enlarger to make roughly 12x b w mural prints. For awhile, I had planned on using a cold-head (Aristo) as ligh t source, but now I'm not so sure that is the way to go afterall. I want the 12 x enlargements to be as sharp, crisp, and vivid as possible. Will I be able to achieve those characteristics with a cold-head, at that printing and resultant v iewing distance, and size of magnification? I realize that a cold-head does di stribute light evenly, decrease the chance of hotspots and the tonal polarizatio n of "soot and chalk", and (at the risk of inciting controversy) perhaps lead to the likelihood of a "higher-quality" print, but will I be sacrificing crispness and possibly sharpness with a diffused light source such as a cold-head? Are t he considerations of mural-printing different than those of smaller size printin g, such that a condenser light-source is thought to be the standard or more sens ible choice when it comes to making prints that size? Then again, if a condense r head would be better, is it even possible to mount condensers to the rear of a CONVERTED 8x10 HORIZONTAL camera-enlarger? Or is a condenser light source reall y only possible or practical in the context of a VERTICAL design enlarger--eithe r by pivoting the head, when printing horizontally, as in the case of the Durst, or bouncing the light with a mirror, as in the case of the Omega? I also have heard that the heat from a 300 (and especially higher) watt bulb can be great, a nd requires forced ventilation (which may introduce complications), as well as c ausing the negative to possibly buckle during long exposures.

Who out there has made bw mural prints with an 8 x 10 enlarger--and especially a converted horizontal one--and if so, what type of light source did you use and which would you recommend?

Note: I am already well aware of Ansel Adams' exlanation of his 11x14 camera-enl arger conversion in his book The Print, so please don't just refer me to that. I am also aware of several major vertical-design 8x10 enlargers, and am more int erested in this question as it relates to HORIZONTAL 8x10 enlargers, and especia lly to homebuilt or converted ones.

Thank you.

[Chris Partti]

Nick,

Regarding one part of your question, Ctein did a two-(or maybe three-) part series on condensor vs. diffuser vs. coldlight enlarger heads in Photo Techniques Magazine a year or two ago. It's the only semi- scientific comparison I've ever seen. He didn't look specifically at the question of doing mural-sized prints, but he did show a number of highly-enlarged print sections to get an idea about whether there were sharpness differences.

I don't have the articles at hand, and I don't completely trust my recall (maybe someone can correct me), but I believe he found that there was a definite difference between condenser and diffused heads in terms of contrast, but not a big difference in terms of sharpness or resolution. I recall that he failed to confirm the common claim that diffusion heads don't show dust as much as condensors. I would recommend getting a copy of the articles.

Good luck.

[Kevin Kemner]

Nick,

I read the article as well and as I recall the determination was that there weren't any differences that clearly made one method of projection better than the next. In terms of constructability, Aristo will custom make the lamp head to match your needs and the cold light should be significantly cooler than a condenser bulb. One positive that comes to mind about cold light and diffusion heads is that you can use printing techniques like mylar masking which is particularly useful on large negatives. There was a two part article in View Camera a couple years ago that you might want to look over. Thats my two cents worth.

[Doug Paramore]

I can't understand why Ctein could not see the difference in printing with a cold light as opposed to condensers. I would be glad to show him if he wants to come down to Alabama. I have printed with both and can see a definate difference, both as to tiny spots on the print and to the lack of the cold light blocking up the highlights. I have one neg which prints quite easily with cold light that is nearly impossible to print with condensers without long burning in times. It is not a black hole with sunlight around it...it is a normal neg of a stump in shade. I have never felt the desire to get my condenser set out of the drawer since switching to cold light. I really like the way cold light handles white things, such as flowers. The seperation of tones is excellent.

Regards,

[james mickelson]

There is no difference between cold light and condensor light sources. They both will make the same print. The difference is in the negative. If you calibrate your system for condensor then it will make the same print as your coldlight calibrated negative. The testing has been done and the conclusion is that the negative must be processed according to the light source that will be used.

[Pete Andrews]

First catch your 10x8 condensers! Unless you already have a set of these beasts, you won't find them easy to come by, and you'll probably be shocked by their size and weight. You'll also notice very little difference between condensers and a cold cathode if you use a normal opal enlarger bulb as the condenser light source. A true collimated condenser system requires a point source of light, such as a small halogen bulb. It's also very fiddly to set up properly, but apart from that, there's absolutely no reason why a horizontal enlarger shouldn't use condensers.

[Scott Walton]

I have printed cold light for years and with a Saltzman 10x10 enlarger with cold light. I would recommend cold light! The prints will be sharp if the negative is sharp. The tonal range will be better by far with cold light. The only real difference in printing is the largeness. It will take more time and careful procedures. Sorry about no info on the horizontals... just used the Salzmans. Nice enlarger if you have the head space. If you do get one by chance, put some padding on the support bars!

[kthompson]

Nick, years ago when I started working in our old darkroom, we were just getting out of making murals in-house. We used an old Beseler MX as a poor-man's horizontal enlarger and projected onto a 4x8 sheet of plywood (with gator foam on it to use pushpins to hold the paper)that was on an overhead track in our darkroom. We processed the fiber-base mural paper in 2 9 foot Kreonite sinks, one with about 25 gallons of Dektol, the other with 25 gallons of fix. We had risers built alongside the sinks, so you could walk back & forth to agitiate the prints, with the sink below waist level. The sinks had built in water jets & standpipes, so you could use them for water washes as well. All in all, it was a big production....much easier to send them out & pay someone to do it, let alone not having to deal with silver recovery, water consumption etc.

We had (still do) an Aristo high-intensity cold head that we used on this enlarger for making regular prints on a drop table stand. But, for the big ones, we switched back to the condensers. In a pinch, we've made a couple of down & dirty murals here in our new lab, sort of the same way. Our darkroom is roughly 18-20 ft. wide x 50 ft. long. It was designed as a mural darkroom, our measley 3 MXTs in it make it seem like a huge cave now. We put move the MX out into the middle of the room and project against a false wall, holding the paper. We do it in strips now, cut down to a 20" width to run through our processor, and we'll "tile" these together. This is a real pain in the butt, and an all day affair. Even with a condenser and fast Kodabrome paper, the exposures can be looong, so having a concrete floor is nice...

Sorry, we just work in 4x5, the labs we use for our murals now will dupe up to an 8x10 usually and work from there. These are big, mural labs. For ideas about horizontal enlargers, look at some of the models made by ESECO. It's a big help to have someone else give you a hand when making these monsters....one more thing, if by "12x" you mean 8 ft. x 10 ft....most roll paper is about 4' wide. There are a few stocks that are wider, but you may find that you have to do this in 2 pieces or more. good luck.

[straton]

I have had great luck with an Omega F condenser head mounted horizontally on a home-made chassis (wooden cradle for head sliding on a cut up aluminum extension ladder!), with a 8x10 camera as the bellows and lens mount. I would be happy to supply plans to anyone interested. I also have a second Omega F condenser head I would be willing to

[straton]

I have had great luck with an Omega F condenser head mounted horizontally on a home-made chassis (wooden cradle for head sliding on a cut up aluminum extension ladder!), with a 8x10 camera as the bellows and lens mount. I would be happy to supply plans to anyone interested. I also have a second Omega F condenser head I would be willing to sell.

-- Jack Straton (straton@pdx.edu), September 25, 2