Beseler Enlarger focusing Issues

As to enlarger focus: Most enlarger lenses fail to project a uniformly tack sharp image, corner to corner as most suffer from coverture of field. The counter measure is to compose and then focus on a selected spot about 1/3 of the way between center and corner. This methodology helps achieve a uniform focus. Now every lens has a sweet spot, likely this will be about 2 f-stops down from wide-open. With that in mind, compose wide-open, focus using your grain focuser, stop-down, now re-focus. The re-focus is important because most enlarger lenses will suffer a slight shift in focal length as you stop down. The countermeasure is to touch-up the focus with the lens set to the actual working aperture you will be using.

 

 

As to type of lamphouse: The condenser enlarger uses two plano-convex lenses that cause the light to hit the negative with parallel rays thus they transverse the negative taking the shortest possible path. Since all negatives have turbidity, the shortest path will deliver higher contrast. A condenser enlarger realizes about 1 to 1 ½ paper grade more contrast as compared to a diffuser enlarger. This extra contrast adds to the apparent sharpness of the image. When it comes to sharpness and pizazz, the condenser enlarger wins every time.

 

 

The condenser enlarger falls out of favor mainly because the resulting prints generally are plagued with dust spots. Dust fluff always sits on the top of the negative. The parallel light of the condenser casts harsh shadows thus the need to spot the prints is increased greatly. A diffuser enlarger is favored mainly because the light is totally diffused so dust fluff cast indistinct shadows thus the need to spot is greatly reduced. The downside is, lower contrast and lower apparent contrast.

 

 

Portrait photographers favor the diffusor enlarger because the resulting prints are more “buttery”. Color negative printers most always choose a diffusor enlarger because of the they mitigate the task of spotting. The “cold light” was introduced when the circulene florescent lamp became available and incorporated into the enlarger lamphouse. They offered a simple way to get a highly diffused light and they run cooler than their tungsten counterparts. Today, the diffusion color printing lamphouse uses an integration chamber. This is a cube or sphere, flat white with lamps that play on the chambers interior walls. The idea is to force the light to reverberate all over the place so that it arrives at the negative plane without direction i.e. totally diffused.

 

 

Also, a flat field enlarger lens is costly but they do the best job. The focal length must be equal to of greater than the corner to corner measure of the negative format, otherwise a vignette is likely.

+1 with Alan.

 

When I overhauled my Bessler 45MCRX a couple months ago I was determined to go back to condensers. I always had heat problems with the conventional 212 bulb despite the heat glass. Thats what convinced me to get the Arista (then later a ZoneVI) cold light back in the early 80s. My Arista had the W45 bulb and the Zone had the newer V54. Either did a good job with and without the 40Y filter I see so many using plus the difference between condenser and cold light was so minimal... just compensate in paper grades to make up the difference. Without filters my cold lights gave me a grade 3 using Illford MGIV FB. Do some negative tayloring, you can get that contrast back easy enough.

 

Since im upgrading everything, I did some experimenting with ordinary house LED bulbs, 60W equivalent- 4000K seemed best for multi grade use. They give off an even light and they are absolutely much cooler, no after glow and instant on, thus eliminating the heat neg popping syndrom. BTW I also painted my light head interior ultra flat black since it was a semi gloss black from the factory... that eliminated some of the typical halo on the light circle generally responsible for clipping the corners a bit.

 

The bulbs worked great but what became a PITA was constantly having to adjust the condenser height to optimize the formats I was working. I switch between 645, 6x6 6x7 9x12 and 4x5 quite often. So tweaking it each n every time just wasn't something I was accustomed to when using the cold light.

 

The cold lights I have are for 4x5 enlargers but I did adapt one for my son on a 23C enlarger. I cut off the lamp head leaving the filter drawer in tact. I had to make a box for the head to sit on and a plate for the condenser bellows to fit in jsut above the neg carrier stage. The diffuser was custom cut white plastic to fit exactly inside the cold lights mouth and held in by a couple tabs of silicon on its edges. You can use a diffuser in the filter drawer instead. That enlarger has been working fine for the past 20 years... now in my garage collecting dust.

 

As for the bulbs in these cold light heads getting weaker... doesn't seem to be a problem at all here and my lights are pretty old. I bought a spare bulb as a back up and still have it in the box waiting for that day.

 

 

Ill post some pix tomorrow if you are interested?

I have had both the Beseler MX series enlarger and the Zone VI Series II enlarger w/variable contrast head. Originally the Beseler had the Aristo cold light retro fitted with the photo cell and the Zone VI stabilizer, and the Series II enlarger had the compensating timer. I often wondered how the compensating timer could compensate for the fluctuations of the 2 grid system. The light output might vary, but the timer would not know which tube (color) was fluctuating. I will admit the Zone VI enlarger was easy to work with, but the light was not as bright as I would have liked. I did speak with a photographer that had acquired one of the few LED Zone VI heads that Calumet sold for the Series II Enlarger. He said the light output was very low and exposures were long for 16X20 prints from his 4X5 negatives.

 

I found using the Beseler setup with variable contrast filters and the stabilizer gave me the printing speed and control over the light output that satisfied me. Then one day I saw an ad in my Craigslist for a Ferrante Variable Contrast Lamp for a Beseler MX series enlarger. I bought it and I found that even though it is a cold cathode ray two grid system [actually 3 grids, but that is another story], the light output is very stable. I printed for years with that system and made some of my best prints. It is a diffusion head that uses the Beseler condensers; I suppose that would be the best of both worlds for Alan.

 

I have never used a color head for variable contrast printing. I do know they have a mixing chamber and the light exits through a diffusion disk. I believe the lamps are "hot", and the fans are necessary to cool the housing. I would assume there might be an issue with negative buckling, but I am sure there is somebody here who can definitively answer that question.

 

Paul

Thanks Alan for explaining the image focus drop-off to rest with a condenser system. I did some test prints after my first posting & seeing the edges fairly sharp with my loupe really put me at ease. I will have to do some more testing to hone in on that sweet spot. Coincidentally I was focusing like you suggested. Wide open, than again once I stopped down for printing. I'll have to do some more testing to find the best area to focus on & F/stop.

I don't do much portraiture, but missing a spec of dust on the negative while printing can be frustrating, not to mention small scratches. Plus it would be nice to have the option of switching between the 2 systems. Heck, I might like the diffusion system for particular images.

Paul Ron, - yes please. That would be great! I have 2 x 23cii enlargers, one, ironically, the newer model hasn't been kept up nearly as well as the older one - which I primarily print from. It would at least give me some idea's. Whether I can find one or build one from scratch with some LED lights. Either way seeing how you modified it would be very helpful.

I hacked sawed the light off the filter drawer and cleaned it up with a file.

I used epoxy to hold the parts together. I also forgot you will need a small plate under teh filter door.

For the plates, you can use 1/4" plywood.

Silicon the condenser head bellows in place.

I used a neoprene weather tape as a gasket for the 4x5 light to sit on.

A diffuser can be put in the filter drawer, I cut mine to fit inside the light and siliconed it in place.

 

When using this setup, I keep the condenser height adjusted to a point the negative carrier can open without any tension.

 

PM me if you have any questions?

 

 

 

Edited February 8, 2018 by paul ron

Your best bet for Cold Light Heads are Aristo and Zone VI. Both are no longer in production, but are usually available on Craigslist or Ebay.

 

I heard you can use the Beseler 23C's color head as a cold light head, just dial the filters to zero. Is that true?

Hi Vincent,

A "cold light head" uses a cathode ray tube, or tubes in a variable contrast housings; cathode ray tube, think neon lights, fluorescent lights. I don't believe the Beseler color head uses cathode ray tubes. The color heads have protocols for mixing the intensity of the blue and green filters for B&W variable contrast papers. Graded papers respond to the blue spectrum only. I am not sure what light you would get with both green and blue set to zero. Either the lamp housing is a "cold light source" or it is not, regardless of filter settings. Don't confuse "diffusion" printing with "cold light" printing. An incandescent bulb can be the illumination source of a diffusion printing system.

Thanks, Paul.

 

I have a Beseler color head in storage with a Beseler 23CIII and 50mm f/2.8 El Nikkor. I hope to set up my darkroom in the next few or more months.

 

We'll see what happens then LOL. I'll only be using Ilfobrom Galerie graded paper.

A color head is also very usefull with multi graded papers ya know? If you ever decide to try it... read the specs and lit on Illfod filters... you can get the chart that shows you how to use a color head as VC filters. Again you will still have heat to deal with now exhausting with a fan. Those hallogen bulbs burn so hot. My color head is still sitting in the garage somewhere.

 

Graded papers love the cold lights. I used the Arista W45 when I got my first one. Back then, AGFA Record Rapid, Portriga and Brovira and other Bromes were popular and all wonderful papers each with their own charachter. I thought I had it all forever. What I liked about my cold light, my 6x7s and 4x5 werent popping anymore plus I like the even light.

That's very helpful Paul, thank you for the pics & notes! One of the things I was grappling with was what would be the best way to mount the head & how to configure the upper bellows. Cutting off the head above the filter drawer solves both those problems. Than it's just a matter of building a couple mounting boards for the cold head & upper bellows for it to all fit together. Living in Arkansas (good god I cringe every time I say that! :D) Craigslist doesn't offer much in the way of used equipment, so Ebay has become my best friend for used photo equipment like a nice cold head. Plus that concept gives me a great starting point if I went the route of building a cold head.

Ryan, keep an eye on the classifieds here and Photrio/Apug.... PHOTRIO

 

I always see them pop up, especially for 4x5s... they seem more common rather than the smaller C23s size. Used they go for about $100 for the ZoneIV.

 

The Arista is just as good... they are both the same bulbs, wiring and blast system.

 

PM me if you do get the lamp? I can giive you my adapter. I have 3 more heads for the 23 including a color head.

 

 

.

Nice! Thank you - That is very generous of you!!! I've started looking on the various forums & sites .Ebay has an auctioning running right now - Zone VI head with the stabilizer control (w/intensity & dry down function) "new in box with instructions", made for Omega D2,D3,D5, & super C. Looking at it, the "dry down" function probably needs the Zone VI timer? Would that head work as it is w/o the Zone VI timer? It has 11 watchers, so it might go above my budget right now. Probably find someone on the forums at a better price, but we'll see. The seller doesn't have any other information as to the model type listed. I'll msg him/her & try to find out. With your modification technique I don't suppose what model the head was designed to fit really matters does it?

I'll measure the hole. I don't think it matters since the light just sits up top.

 

as for stabilizers n dry down, never used any of it. dry down? hahaha close is close.... I'm not making posters, I'm making photographs.

I never saw the need for a dry down feature either. Observations in different papers & the test printing sessions work just fine for me. :D After looking at one for sale on APUG (not sure if it's sold yet), They look like the same model - even though Apug one states its for the 45MX enlargerl. The pictures on Ebay doesn't show the front of the regulator, where the stabilizer line connects to the lamp & monitors the light output I believe. The one on APUG says it's for graded paper, which I'm waiting to hear back from the ebay seller for more details. I looked for an explanation in the difference between the graded vs VC head in regards to printing, but does it really matter if one uses a graded head with VC paper & use the contrast filters when called for, or VC head on graded paper? Is it the color temp of the light?

Contrary to popular belief, diffuser heads do not give a less-sharp image than condenser heads. Not when an opal lamp is used with condensers anyway.

 

Film grain is equally well defined in the print when using a diffuser head as with a condenser. The main difference between the two is a slight drop in contrast with the condenser head when printing silver-image negatives. (This is due to light scattering taking place proportional to density with a condenser/point source system, which artificially increases contrast.) The effect can easily be counteracted by a slight change in paper grade.

 

There is no 'buttery' effect - whatever that means, and very little masking of dust, unless it's a good distance away from the emulsion surface. As on the surfaces of the condensers or top surface of a glass carrier.

 

I think people see the word 'diffuser' and immediately associate it with a softening filter over the lens. This is not the same thing at all as diffusing light prior to focussing. The image plane remains just as sharp, and any softening is mainly in the imagination of people that have never used a diffuser head.

Edited February 10, 2018 by rodeo_joe|1

"The main difference between the two is a slight drop in contrast with the condenser head when printing silver-image negatives."

 

- That should, of course, read "..a slight rise in contrast..". Sorry!

I never saw the need for a dry down feature either. Observations in different papers & the test printing sessions work just fine for me. :D After looking at one for sale on APUG (not sure if it's sold yet), They look like the same model - even though Apug one states its for the 45MX enlargerl. The pictures on Ebay doesn't show the front of the regulator, where the stabilizer line connects to the lamp & monitors the light output I believe. The one on APUG says it's for graded paper, which I'm waiting to hear back from the ebay seller for more details. I looked for an explanation in the difference between the graded vs VC head in regards to printing, but does it really matter if one uses a graded head with VC paper & use the contrast filters when called for, or VC head on graded paper? Is it the color temp of the light?

 

 

the ones I have used on the 23 were for the 45mx. round body.

 

there are newer heads that have 2 bulbs in them... one bluish the other greenish. same zone maker puts m out.

 

to use vc filters on my setup, 6x6 gels cut down to fit the filter drawer. that's why I did my mod... to keep the above neg holder.

The color temperature of the light source matters for VC paper. When I had an early Zone VI cold light head in my Omega D2 I used a 40 cc yellow filter to get the color temperature closer to a tungsten bulb and then used Ilford Multigrade filters below the lens to control contrast. This worked very well. Without the yellow filter, contrast was higher than it should have been. I also found the dry down control to be very useful. Paper does dry down, and delicate highlights can gray out if you don't take it into account.

someone on large format photo forums was telling me how he built an RGBW light for his enlarger using an RGBW flood light with some modifications. this is the unit he recommended......

 

 

Newled High Powered 100W Waterproof RGB LED Flood Light, Color Changing LED 16 & | eBay

 

 

getting any ideas yet?

Thanks AJ.

Yeah, I'm starting to get some good idea's Paul. Using a RGB LED light, wire it up and build a diffusion filter or chamber to scatter the light. I keep reading the best source is a RGB LED light when building a cold head. Why is that? Does the combination of the RGB mixture light temp best match what the sensitivity of the emulsion requires? Or does it have more to do with being able to dial in the color temp best matched for graded or VC paper, either "white" - yellow - magenta, etc.?

I printed for years with that system and made some of my best prints. It is a diffusion head that uses the Beseler condensers; I suppose that would be the best of both worlds for Alan.

- Is this another setup that is common? A cold head using the condenser, wouldn't that just be a cold head but not a cold diffusion head, which seems like another option to keep in mind.

they make a 2 bulb cold light... vcl4500... . it allows you do dial in the amount of blue vs green from each lamp to get the grade you need.

 

I saw that about using condensers with the cold light. mmmmm... I wonder?

 

the rgb led is another option. lots of DIYers are doing it, so plenty of info out there.

 

either way, you still need to adapt them to your enlarger.

I'm researching as we speak. Whichever I go, homemade or bought, the head is mounted like in your modification, as if I were printing the largest negative capable for the enlarger, with no need to adjust the head like in a condenser system - correct?

As long as the diffuser is close to the negative stage, no changes with different film sizes will be necessary--one of the reasons I put the Zone VI cold light head in to replace the condenser head in my Omega D 2.

right, no need to adjust the condenser height. my mod just needs the light to sit on top of it. the light has to cover the entire neg evenly.

The Ferrante system required the condensers. When using the Zone VI or Aristo cold light, the housing is as close to the negative as possible; the lamp housing bellows is collapsed completely. The Aristo or Zone VI lamp that fits the Beseler or Omega 4X5 enlarger is the same unit; the Beseler needs a special collar. The condensers are replaced by the Beseler collar and the lamp housing sits into the collar. And notice the seller does not indicate which lamp this is; Hi Intensity, balanced for variable contrast, graded papers.

 

The Zone VI Stabilizer requires the "photo cell" in the lamp housing to read the intensity of the lamp. The photo cell plugs into the stabilizer; the stabilizer sits between the enlarger and your timer. From the picture on ebay, it appears the cold light is in the Omega housing. It should lift out; ask the seller if it separates or is a permanently sealed unit. You are aware it is too big for the Beseler 23C?

 

Paul

Edited February 12, 2018 by paul_hoyt