Beseler 23C 4x5 modification, DIY LED head

[Bob F.]

You might want to read this ((there was a url link here which no longer exists)) thread and check out Huw's site (http://www.huws.org.uk/). Do a search on "LED ENLARGER HEAD" on the archives here for more.

Cheers, Bob.

 

[wirehead]

I use superbrightleds myself.

As far as the circutry for custom stuff goes, you need to have resistors to control the voltages. Search for "LED Resistor calculator" and that let you figure out what resistor you need.

 

[Curt]

Thanks Bob for the info.

Curt

 

[Nicholas Lindan]

Then the relay is connected to the timer?

Yes: the relay coil is wired to the timer where the enlarger would plug in. The contacts for the relay are wired in series with the LED's so current only flows to the LEDs when the relay is energized. The power supply for the LED's is always on/plugged in.

Be sure to use a relay with a 120V/60Hz coil [or 220/50 if in Europe, etc.].

 

[konakoa]

I had a thought on Curt's edge burning idea. All that needs is some means of brightening the corners of the light source. The LEDs have light intensity to spare, so I could see some thin nearly transparent material, like tracing paper or a lightly fogged sheet of film, cut into a oval and placed inside the box on top of the diffuser. That would darken the center, but leave the corners bright. Some fiddling of the size of the oval would be needed, but I think that would do it.

Heck, a filter tray could be made that would slide in and out of the head itself. Mount the oval on a clear sheet of plexiglass, and slide it in and out of the head (above the diffuser) as needed.

 

[jstraw]

Yes: the relay coil is wired to the timer where the enlarger would plug in. The contacts for the relay are wired in series with the LED's so current only flows to the LEDs when the relay is energized. The power supply for the LED's is always on/plugged in.

Be sure to use a relay with a 120V/60Hz coil [or 220/50 if in Europe, etc.].

Thanks.

 

[resummerfield]

.....All that needs is some means of brightening the corners of the light source. The LEDs have light intensity to spare, so I could see some thin nearly transparent material, like tracing paper or a lightly fogged sheet of film, cut into a oval and placed inside the box on top of the diffuser. That would darken the center, but leave the corners bright. Some fiddling of the size of the oval would be needed, but I think that would do it......

Aristo handles that problem by painting a grey spot on the inside top of the case.

 

[Curt]

Danny, do you think that a Beseler 45 could be modified like you did with your 23 to accept a larger negative size? I was thinking of course of a 5X7 inch. At any rate I am going to be doing the conversion as I bought a 45 "complete head only" and expect it in a week or so. I just couldn't find a 5X7 enlarger so thought I would make one. I have a column already made with 12 bearings on three sides and a head that moves smoothly straight up/down and is rigid. I have an Aristo 5X7 head to use until I make an LED head. When I see the Solars and Elwood's I believe I can make one that will be a dream to use. I have a couple of lenses that will cover the format also and one that will cover 8X10 if I decide to later. I really like the LED path, it looks very promising.

Thanks again,

Curt

 

[jeroldharter]

Danny, do you think that a Beseler 45 could be modified like you did with your 23 to accept a larger negative size? I was thinking of course of a 5X7 inch. At any rate I am going to be doing the conversion as I bought a 45 "complete head only" and expect it in a week or so. I just couldn't find a 5X7 enlarger so thought I would make one. I have a column already made with 12 bearings on three sides and a head that moves smoothly straight up/down and is rigid. I have an Aristo 5X7 head to use until I make an LED head. When I see the Solars and Elwood's I believe I can make one that will be a dream to use. I have a couple of lenses that will cover the format also and one that will cover 8X10 if I decide to later. I really like the LED path, it looks very promising.

Thanks again,

Curt

In one of the old Photo Techniques supplements about black and white printing I read an article about someone modifying a Beseler (45 VXL I think) enlarger to accomodate an Arista 10x12 inch lightsource. Basically, he used a series of cardboard risers, each a little bigger than the first, to expand the opening to the bellows. He also made a trap door to hold a VC filter under the light source and he made a negative carrier which seemed like the hardest part. I think those old issues are still available as reprints.

 

[resummerfield]

..... do you think that a Beseler 45 could be modified ......to accept a larger negative size? I was thinking of course of a 5X7 inch......

Almost any enlarger can be modified for a larger negative, provided the distance from lens center to the column is sufficient. You may need to add an auxiliary bellows above the current negative stage, and then fabricate a new neg stage for a 5x7 carrier. It shouldn't be difficult, just keep everything aligned. The Beseler 45 series seems especially well suited for these mods--just look at the 810 conversion! Good luck, and keep us posted!

 

[konakoa]

Curt, if the head of a 45MX(T) is anything like the 23C, it should be a bit oversized and will lend itself well to a little tinkering. A lifetime ago I regularly printed on some 45MXIIs in college, and I remember the negative stages being quite big. I have a 35mm mounted slide carrier for a 45M here, (I loved making ciba/ilfochromes) and I would think from looking at it that 7" is certainly doable.

Keep us posted on your progress. I'd love to see what you've made!

 

[Curt]

Hello Jerold, Eric, and Danny,

When the bellows head unit arrives I will go to town on it. I will work out the heights, dimensions and optical alignment and keep the results posted. I have two cold light heads that I bought a couple of years ago, one is an Aristo 5X7 and the other is an Aristo 8X10, just over sized for 8X10. My current favorite format is 5X7 but I don't see any problem with making an 8X10 after the 5X7 is finished. When it's finished I plan on making the LED light sources. I do have a square bellows that is 8X10 in the inside that could be used as an aux bellows above the existing unit.

Curt

 

[jeroldharter]

Scroll down this thread to find the photos of an enlarger mod to accomodate larger formats:

(there was a url link here which no longer exists)

 

[Curt]

Hello, I took another look at that thread and saw the photos of the conversion. It looks a bit heavy, not to be too critical, and there is a lot tape. I hope to have a more "clean" conversion that won't collect dust. I am looking to Aristo for a new bulb for my old Aristo 5x7 cold light head. Cold lights and other units have differing dimensions. A good design would take this into account and have the ability to change light sources in the future. I don't know if what if any color heads are available in 5X7 as I do BW exclusively. The LED head might take some time because I would like a VC head. I am sticking to the Aristo one for now because I have it already. I am waiting on the delivery of the Beseler complete bellows head unit to arrive. I measured the inside of the 45 and the bellows appear to be 7 inches square. And cutting a 5X7 out of a Beseler negative holder doesn't leave much "meat" left. With a negative that large a negative holder like the negaflat is needed and most conversion and larger holders use glass holders. I am not fond of glass holders so I am looking at some designs for a holder that stretches a negative and keeps it taunt. Making a conversion on top of the enlarger doesn't affect the original equipment and thus the resale value of it. My stepfather was a designer and estimator and always came up with designs that were added on in a seamless way but didn't cut into the original equipment. His philosophy was there is always a better way to do it if you work at it.
I bought a Canham bellows, new on eBay, and have a new rack and pinion along with a plank of Mahogany to make a 5x7 field camera somewhat like Deardorff and others. A field camera of my own design. A folding field camera that doesn't weight a ton and is easy to use. I built a 4x5 clam shell type field camera out of cherry and brass and it still works great after 20 years. I made the tapered bellows also and it is still light tight. I put a layer of aluminum foil in between the paper and cloth. That seem to do the trick.

5X7 is a format that I can continue with because I have some medical conditions. I was able to use my Kodak 2D in the Valley of Fire on a trip to LV with my wife a while ago but I know I can do better in design and weight. 4 feet of brass rack and 4 pinions cost me over a hundred dollars. I bought a pair of Deardorff springs on eBay, everything else is shop made and milled.

I started out with a Kodak 2D and a Seneca Improved 5X7 then got a bunch of holders and tanks and hangers, the whole kit of what's needed. Lenses were not a problem because I also have a Kodak 2D and a Seneca Improved 8X10. I used a medium format so long that 8X10 is almost too large for me and too heavy now. 5X7 is just perfect in size and affordability.

Curt

 

[MurrayMinchin]

Hey, now that's pretty cool

I have this forum, 'Camera building and Modification' on ignore, but found this thread via google! I'll be watching this for further (VC) developments.

Murray

 

[Curt]

My Beseler 45 bellows assembly arrived today and I am already looking at it for any modifications. I don't think I can do the modification that Danny did with his 23 but I will look at it first to see if it is possible. Then I will look at an above the top bellows unit, where the stainless steel slides are, and make an assembly with film holder lamp holder etc..

On another note, I am looking at my Beseler Universal head that is missing a controller unit to make it work. This unit has a single bulb, 83 volt, and the three knobs in front to adjust the light temp. If a person had this head and no controller I believe that the bulb could be run from the power supply, the 83 volt transformer inside, with a relay to a timer. The circuit boards would not be used and the knobs could be calibrated. I have a color analyzer to do it. The knobs could be marked for the VC grade positions 1 to 5.

My other dead head Beseler is the head that has three light bulbs, 83 volt, that are dimmed individually to create the correct color. Each bulb would have to be dimmed and the three together on one relay.

Curt

 

[Curt]

This is the head complete with bellows and all hardware. The top bellows would have to go and the negative stage cut out similar to the 23c modification. It's nearly 7 inches across, I would need to get, make or otherwise use a 5x7 negative carrier to see if the opening would be large enough. I believe it just might be. It would save on having to make a box to hold the carrier and use the existing equipment. Might be pretty slick if it works out. LED's anyone?

 

[konakoa]

Update

I recently changed from Kentmere paper on this enlarger to Oriental. I didn't realize it but the contrast range IS limited with VC paper and these LED lights. The lower grades, -1, 00 aren't a problem. However, the harder paper grades - about 4 and up - have to have a ultraviolet component in the light to work. No UV, no hard contrast grade. Ctein in his book Post Exposure has some interesting info on this.

The Kentmere VC paper I was using seems to have a really high inherent contrast. When I did my initial tests I didn't have a problem getting a hard contrast with it on my white LED light. Most of the time I had to use a #1 or #0 filter to bring the contrast down to a normal range of tones. Yet when I changed my paper to Oriental VC, I found I couldn't get above roughly grade 3 1/2. Same with Ilford MG, etc. The LEDs I used in my enlarger don't put out any UV, so I can't get the really hard paper grades.

To anyone building a LED lightsource with white, green or blue LEDs, please be aware of this shortcoming.

 

[JRJacobs]

Danny -

You are correct about the Kentmere paper - I just started using it and found it to be about 1.5 grades contrastier than normal VC papers.

Interesting about the LED light at higher grades.

 

[Lee L]

For those who wish to experiment: There are discrete component LEDs in the UV and deeper blue range 400-420nm, as opposed to the more standard blue LEDs in the 470nm range. That might boost contrast for someone building their own source or willing to replace LEDs in a stock LED light bar.

Lee