Frankenlarger; or, the Modified 23/45

[Harry Callahan]

...and that would be the Callier effect, which I've always struggled to understand, until about 48 hours ago. Here's an excerpt from an article that someone sent me, which helped immensely:

Interesting article, but it only does touch the point i was trying to make - i`ll stay on the article for now though:

So it's basically a zone of confusion around the each grain, and the more collimated the light is, the more contrasty the print seems to be...but one could also say that the more distance there is between the lens and the print, the larger that confusion zone becomes. This is why that certain look I mentioned earlier is important, and why it happens in small enlargements: they don't have the insane level of detail and tonal separation that you find in a contact print, but they also exactly look like typical enlargements. They are deep, dense, and - when shot on a diffusion enlarger - ethereal.

I assume that by "zone of confusion" you mean flare around each grain. This flare of course does increase in size if you print bigger, but the ratio of flare to the bigger grain on the bigger print should remain the same.
The reason for bigger prints being lower in contrast should be that the light is spread over a bigger area and by that the brightest part of the negative (the shadows on the print) become less bright in relation to the darkest area of the negative (the highlights on the print). If you print smaller, higher contrast on the print is obtained.

The scattering is least where there is little silver deposit, and most where there is the most silver. The deflection of the light is small but becomes significant in the case of a projected image. In an enlarger, much of the scattered light is deflected sufficiently to miss the lens altogether; if this occurred uniformly in all negative areas, it would make little or no difference, but the amount of deflection actually depends upon the way in which an enlarger is built.

This effect also should depend on the focal length used in printing. The shorter focal length is the closer the lens is to the negative and the more scattered light should enter the lens - the longer focal length is the further away the lens is from the negative and the less scattered light should enter the lens.

Back to my point:

Yes, the interior of the lamp enclosure does have an impact on what light is emitted; darker colors and matte surfaces absorb more, and lighter colors reflect more.

I don`t feel that you gotten my point. It is this:

A single "grain" on the print actually is a hole between several grains on the negative. Light only can pass the negative where there is no grain, so the black spot on the print actually is a gap between several grains on the negative.
If the light from whatever light source only was passing the negative at an 90 degree angle, the "grain" on the print would be as sharp as possible. But as you said it`s impossible to have vertical light rays only, therefore some rays will pass the hole in the neg at a different angle than 90 degrees.
Those rays will increase size of the "grain" on the print. Rays going only at 90 degrees will print the hole in the neg just the size it is, but rays going a different angle will expose the paper where actually no light should fall on.
By that the "grain" on the print will print bigger than it actually is, it will print with a grey corona - making the grain less prominent.
I think that with a diffuser close to the neg this effect even does increase - as with a diffuser right to the neg even more non-vertical rays will be able to pass the neg. Maybe that`s why you like this light source.

The effect i`m trying to describe here should blur the grain structure, leading to more homogenous areas on the print.

 

[MTGseattle]

Another thread that is making me happy. May I come down to your garage/shop with a box/bag of beverages and a folding chair? I will only laugh if you too are laughing. I promise I can mess up the strike of a retaining pin through a shaft like the best of them.

This is Also reminding me of my Elwood 8x10 enlarger journey. the studious will note that I have not yet posted pictures. There's a good reason for that.

My quick thought on the rear "X-braces" of the Beseler 45. One could duplicate those with turn buckles and possibly true up the frame in the process.

You may be hanging up on some aesthetics, but just mount a couple of horizontal pieces of wood or "L" channel or something to your wall to give you the mounting surface you need.

That height adjustable desk is a great idea. There are 1 or 2 companies out there from which you can buy powered legs only for anyone interested. Home Depot sells a manually adjustable workbench/table that I like but the mechanism feels a bit weak imo.

 

[Sundowner]

The effect i`m trying to describe here should blur the grain structure, leading to more homogenous areas on the print.

Harry, I think we are talking about the same thing; give me a bit to really digest what you're saying and I will respond more thoroughly.

Another thread that is making me happy. May I come down to your garage/shop with a box/bag of beverages and a folding chair? I will only laugh if you too are laughing. I promise I can mess up the strike of a retaining pin through a shaft like the best of them.

Anytime! You'll have to excuse the unfinished ceiling, overall clutter, and drifting piles of bunny fur: it's shedding season.

This is Also reminding me of my Elwood 8x10 enlarger journey. the studious will note that I have not yet posted pictures. There's a good reason for that.

I usually don't show much of my work, but this and the oversized plywood tray dry sink are insane enough to warrant documentation. But yeah; you need to post some images of your own enlarger project. Thread title: "Elwood Blues". You're welcome.

My quick thought on the rear "X-braces" of the Beseler 45. One could duplicate those with turn buckles and possibly true up the frame in the process.

On my other 45 - the one I rebuilt from the three scrap chassis - I replaced the back stays with a pair of 36" double-adjustable control arms from a pair of 1/4-20 stainless turnbuckles and some 7075 aluminum tubing; it worked really well to micro-adjust the overall pitch of the frame...so I think you're on to something with doing the same for the cross-braces. The mounting brackets on a 45 hoop chassis would make it simple...at least, as long as you don't mind them mounting in single-shear: one would have to mount inside the bracket and the other would have to mount outside of it, otherwise they would intersect in the middle just like the factory ones do. And the factory braces suck, so that would be uncool.

You may be hanging up on some aesthetics, but just mount a couple of horizontal pieces of wood or "L" channel or something to your wall to give you the mounting surface you need.

Would 8020 aluminum work for the wall mounts? I've been looking for an excuse to do some work with T-slot extrusions and this seems like an ideal place to use them; they'd go directly against the wall and let me offset the enlargers to any lateral position I like, regardless of the actual stud locations.

As far as the mounting brackets themselves are concerned...

Pictured: I have...a plan.

I picked up this DiAcro last year for WAY too little, mostly because it needed a serious bath. I've used it a few times for small/simple folds, but I've been itching to push my skills a bit...so how about I try to build a 16-gauge wall-mount for a 23C? I'd like to develop one that's simple and strong and which doesn't require any modification to the existing chassis. I think that with a bit of work I can draw up exactly what I need in Fusion, have a local shop laser-cut the sheet, and then all I need to do is bend it to shape, weld where needed, and then finish it. Shouldn't be too hard, and if it works it could be a ready-made solution for anyone that doesn't have shop tooling to make their own. Maybe. We'll see.

That height adjustable desk is a great idea. There are 1 or 2 companies out there from which you can buy powered legs only for anyone interested. Home Depot sells a manually adjustable workbench/table that I like but the mechanism feels a bit weak imo.

These were produced by Hermann Miller, for... someone. I can't figure out who, exactly, but ChatGPT and I are still attempting to solve that mystery. I'll definitely post that info when/if I find it, because I'm pretty sure that something similar still exists in current (early 2025) production. I highly suggest looking around for secondhand units for anyone that's interested in doing this, but for those that prefer to buy new: check out some of the Ikea leg sets: we have one of theirs in my partner's home office and it's very nice. I don't think it's quite as strong as these units, but once it's locked to a wall there would be no discernible difference.

I've looked at that HD bench/table as well; they also have a toolbox with the same kind of mechanism. My thoughts mirror yours: that mechanism is a bit flimsy. Running it up and down...eh, it just didn't feel great to me, and that was with it unloaded. I am concerned that with weight on it - big enlarger, transmission housing, whatevs - it would be pretty stiff.

 

[MattKing]

The reason for bigger prints being lower in contrast should be that the light is spread over a bigger area and by that the brightest part of the negative (the shadows on the print) become less bright in relation to the darkest area of the negative (the highlights on the print). If you print smaller, higher contrast on the print is obtained.

That is part of it.
The other really important part is very subjective. Contrast tends to create more of an impression on us subjectively when we observe it in a small print and/or are closer to the print.
To create the same impression with a larger print that is viewed from farther away, you will need to increase the contrast.
It is one of the many reasons why backlit transparencies are used in place of prints for large installations - they are inherently more contrasty, due to a larger capacity for luminosity range.

 

[Lachlan Young]

The 23C return springs will hold a 20-pound dumbbell stationary, although only just

And it won't be difficult to upgrade those constant force/ tensator springs if you want. That said, a flat panel LED diffusion system would not be a bad upgrade & save quite a bit of weight.

 

[Sundowner]

That is part of it.
The other really important part is very subjective. Contrast tends to create more of an impression on us subjectively when we observe it in a small print and/or are closer to the print.

One of the other reasons that I print smaller, usually; I can get a lot of dynamic tonality without having to work at it so hard. Usually, I kind of have to dial it back a bit, because I get overly-contrasty stuff.

To create the same impression with a larger print that is viewed from farther away, you will need to increase the contrast. It is one of the many reasons why backlit transparencies are used in place of prints for large installations - they are inherently more contrasty, due to a larger capacity for luminosity range.

I did not know that! Very interesting! Makes total sense now that you've said it, though.

And it won't be difficult to upgrade those constant force/ tensator springs if you want. That said, a flat panel LED diffusion system would not be a bad upgrade & save quite a bit of weight.

You know, I did think about looking for some kind of spring upgrade, but I wasn't sure where to look. I figured the spring stock could be bought in bulk, but that's about as far as I've thought about it, thus far.

I think the LED head will probably shave some, yes...but I'm not sure how much. In my current [very rough] design the LED mounting plate and heat sink alone are almost two pounds; I don't expect the framework to be much less even if I build it from carbon or some other exotic material. Side panels will be a few ounces, as will the LEDs and wiring. The plastic diffuser will also be a few ounces. Hardware will add some weight, along with the other bits of randomness: light seals, connectors, thermal paste, paint, etc. I've no idea what the 45 head brackets will weigh, but I can call them a pound all together...so if I had to guess, I'd say that an LED head be every bit of five pounds by itself, with another pound or two of bracketry, possibly. Maybe a four to five pound savings?

 

[Lachlan Young]

but I wasn't sure where to look

'Constant Force Spring' is the thing to look for - they're a standard industrial part, just treat them with as much respect as a leadscrew on a lathe and you'll be ok.

 

[Sundowner]

'Constant Force Spring' is the thing to look for - they're a standard industrial part, just treat them with as much respect as a leadscrew on a lathe and you'll be ok.

Oh, that thing I bump into all the time when I'm moving stuff around in the garage?

I got some pretty decent results from that search term, so that helped a lot; thank you. I'll need to do some research before I can figure out what to get, but the parameters for the spring look pretty basic so far: width, thickness, material, etc. I don't exactly know the preload, though...and this would honestly be a lot easier if I had any clue as to what I'm doing. Ugh, time to spend all afternoon with ChatGPT tutoring me, again...

 

[Sundowner]

Pictured: Prototype.

That's a very rough version of a bracket for the 45 head...but it's progress, all the same. Naturally, as soon as I pushed the "Print" button I figured out a better way to build it, but that's okay; this is very much a tutorial part for me, so we'll see if it works as a proof of concept.

Edit: that totally didn't work as a proof of concept, but not by want of design. I made the supports too dense, so it was impossible to clean them off...so that was some wasted filament. Ugh. But, as stated, I think I have a more refined idea anyway...so, I'll try to work in that direction. Sometimes you just have to start building something in order to understand whether or not it'll work.

 

[MTGseattle]

That is part of it.
The other really important part is very subjective. Contrast tends to create more of an impression on us subjectively when we observe it in a small print and/or are closer to the print.
To create the same impression with a larger print that is viewed from farther away, you will need to increase the contrast.
It is one of the many reasons why backlit transparencies are used in place of prints for large installations - they are inherently more contrasty, due to a larger capacity for luminosity range.

I think this too is why wet-plate collodion has such a unique quality. It basically has to be back lit for viewing.

 

[MTGseattle]

8020 extrusion should be fine (albeit expensive) for the basic wall mount sub-frame. afaik, the 8020 site lists a lot of specs if you're concerned at all about shear or other forces which for a largely static thing shouldn't matter very much.
Until you end up with a 200lb load spring and send the head assembly up into your ceiling. Ha ha

 

[Sundowner]

I think this too is why wet-plate collodion has such a unique quality. It basically has to be back lit for viewing.

I'd like to work with that process, someday. Possibly when I have room for an actual studio.

8020 extrusion should be fine (albeit expensive) for the basic wall mount sub-frame.

I think I can get it for somewhere between $60 and $75, plus shipping. Haven't found a local supplier, yet.

afaik, the 8020 site lists a lot of specs if you're concerned at all about shear or other forces which for a largely static thing shouldn't matter very much.
Until you end up with a 200lb load spring and send the head assembly up into your ceiling. Ha ha

I don't think there's going to be enough weight on them to matter. I think I can use a wide, flat piece for the bottom rail and a standard 15-series for the top; that should provide load-bearing for the bottom and enough rigidity to control pretty much anything that's going on at the top.

Also, just from some rough measurements: I don't think clearance underneath the head is gonna be an issue. I'll know more here in a bit...probably around the time I get a "wow, didn't expect it to be that much for a single bracket" quote from the local laser shop.

 

[Harry Callahan]

Harry, I think we are talking about the same thing; give me a bit to really digest what you're saying and I will respond more thoroughly.

It`s not that important anyway, as the effect i am thinking of only should be visible on big prints.

That is part of it.
The other really important part is very subjective. Contrast tends to create more of an impression on us subjectively when we observe it in a small print and/or are closer to the print.
To create the same impression with a larger print that is viewed from farther away, you will need to increase the contrast.
It is one of the many reasons why backlit transparencies are used in place of prints for large installations - they are inherently more contrasty, due to a larger capacity for luminosity range.

Interesting. I was aware that backlit transparencies do have greater tonal range than a print, but i havn`t heard of contrast having greater effect if looked at close before.

 

[Sundowner]

Pictured: Let's go about this a different way.

 

[Sundowner]

Pictured: Promising...

This is just PETG on a draft setting with some improvised/incorrect hardware, so it's entirely too flexible and at least 58% more janky than it should be...but it's enough to show that an interfacing bracket utilizing the factory head-pivot-shaft-thingy on the 23C carriage could be made to work.

That being said: as soon as I pressed the "Print" button, I figured out a better way to build it. I think - think - I can get this done with two pieces of aluminum and some careful drilling, and possibly give the head some adjustment in the process.

 

[MTGseattle]

I feel like there's a structural steel "T" like that in the Simpson Strong-Tie catalogue. It would only solve 1 problem for you, and you would still have to drill the appropriate holes since it's meant for teco nails and not nuts/bolts.

I sure do dig all of the stuff that 3d printers let people come up with. (side-eye at wallet). My buddy down south has already crashed his Dji Avata and printed a new sub-frame and restored it to flying duty.

 

[MTGseattle]

Here's something to do while your next print job is going;

Ian RuhterIan Ruhter | Silver & Light

Ian Ruhter created the world's largest wet plate collodion cameras to make photographs in a way that has never been seen before.

www.ianruhter.com

 

[Sundowner]

I feel like there's a structural steel "T" like that in the Simpson Strong-Tie catalogue. It would only solve 1 problem for you, and you would still have to drill the appropriate holes since it's meant for teco nails and not nuts/bolts.

This version is pretty flexible, but since it's a draft I didn't really expect otherwise. This being said: five options readily present themselves.

1. Invest in a hardened steel nozzle and a filament with "CF" or similar in the name. Fiber-reinforced filament is stronger, dimensionally-stable, and especially good for parts like this...and I have been wanting to work with it, anyway.
2. Restrict the printed parts to the shaft bearings blocks/tabs, and just go with laser-cut aluminum for the bracket. Rough pricing says that if I can get one for less than $20, cut from pretty much whatever alloy I want.
3. Do the exact same thing as #3, but make the bracket in-house; I already have some 6061, and that would be perfect for it...but it'll take awhile to create because I don't really have the tooling to work with heavy sheets. It would be old-skool saw and file work.
4. Revise the bracket to be more construction/printer friendly, which may need to happen anyway, now that I've seen the prototype on the head rail. I may actually be able to do this with nothing more than bar stock.
5. Redesign the entire system of connection to something that works better, overall. Definitely the most work, but probably also the rest results; it'll just be hard to keep it as a bolt-on conversion unless I really work at it.

So, yeah... it's very likely that I'll go with some variant of 4 or,5, at this point. I basically have 4 worked out already, but 5 could take a lot of different directions. I really like the idea of being able to adjust the entire head up and down on the chassis, and I have a idea about to do it, but it isn't simple or elegant, and that's how I know it's wrong.

I sure do dig all of the stuff that 3d printers let people come up with. (side-eye at wallet). My buddy down south has already crashed his Dji Avata and printed a new sub-frame and restored it to flying duty.

I bought mine as a kit, assembled it, and have really enjoyed learning how to use it. Granted, I still don't really know much about it, but I'm honestly enjoying working with it...and parts like these are the perfect way to learn and grow my skills.

Here's something to do while your next print job is going;

Ian RuhterIan Ruhter | Silver & Light

Ian Ruhter created the world's largest wet plate collodion cameras to make photographs in a way that has never been seen before.

www.ianruhter.com

I am so glad that you posted that link, because I saw that video back in the dim past and had lost access to it. Thank you! I think I liked his older version better, but still...that. That. Yes.

 

[MTGseattle]

Ian Ruhter is to wet plate what Clavin Grier is to carbon transfer printing. admittedly, Calvin throws a lot more "tech" at his workflow, but I would call them both at or near the apex of the respective crafts.

 

[Sundowner]

Ian Ruhter is to wet plate what Clavin Grier is to carbon transfer printing. admittedly, Calvin throws a lot more "tech" at his workflow, but I would call them both at or near the apex of the respective crafts.

Seems that way, for sure. I love the extra-big-ass plates; it's possibly not where I would go with that process, but I definitely respect what he's doing with it.

I made progress on the 45 head situation today; I've discovered that you can mount nearly anything to anything else if you drill enough holes or use enough adhesive...but since I don't want to do any of either, options are limited. I think I have a mounting solution that's good enough for a rough draft, so I'm printing out the first piece of it tonight. If it proves feasible - and I'll post pictures tomorrow for critique and improvement suggestions - I'll start thinking harder on materials, hardware and the like; I want this to be a completely bolt-on conversion...or at least as close to that as is possible, within reason.

I also need to start making some solid decisions on the head that will go on this thing...and that's a whole new ball of wax.

 

[Sal Santamaura]

...I also need to start making some solid decisions on the head that will go on this thing...and that's a whole new ball of wax.

You might think about working with Juergen Heiland on that. I have a 23CIII that he and I custom-configured with his LED light source more than a decade ago, before he started making direct-fit products for that enlarger. It was a very satisfying collaboration.

Another thing you might consider is offering a kit to accomplish this conversion. Like you, I print small. My LPL-4500II sits in boxes in a closet, and needs to be assembled/disassembled on those occasions when I summon the motivation to enlarge 4x5. I'd be interested in converting the Beseler so it wouldn't require so much effort to make an 8x10 from 4x5 negatives. Could be a lucrative business for you.

 

[Sundowner]

You might think about working with Juergen Heiland on that. I have a 23CIII that he and I custom-configured with his LED light source more than a decade ago, before he started making direct-fit products for that enlarger. It was a very satisfying collaboration.

I'm definitely open to that; thank you for the suggestion!. After thinking on the matter it seems that the ideal situation is to make this conversion friendly to any Beseler 45 head - condenser, Aristo, LED, Beseler color heads, etc. -because that increases the versatility and usefulness; I'm not a fan of one-trick ponies. That being said: this may be difficult because of the varying weights of the various heads, but I think some kind of replacement spring would go a long way to solving that issue, should it come up.

Another thing you might consider is offering a kit to accomplish this conversion. Like you, I print small. My LPL-4500II sits in boxes in a closet, and needs to be assembled/disassembled on those occasions when I summon the motivation to enlarge 4x5. I'd be interested in converting the Beseler so it wouldn't require so much effort to make an 8x10 from 4x5 negatives. Could be a lucrative business for you.

Longer answer...

Whenever I build things, I generally try to keep "Is this a potential product for other people?" in my mind. That perspective is not so much about monetizing an effort, but rather, refining and improving the design; by thinking about a project from the perspective of someone that doesn't have a printer or a mill or a collection of specialty wrenches or whatever, I usually come up with much simpler and nicer solutions.

This being said: most of my designs don't become products because they're incredibly unique to my own requirements...but a compact 4x5 that can be made from readily-available, standard-issue parts and a single box of conversion bits is something that a few folks may be interested in. I think you just highlighted a key use-case: small workspace, occasional need for larger-negative capacity, and a portion of the necessary parts already on-hand. If I can make a kit that essentially solves that problem with an hour of work, give or take...yeah, I might be able to do something with that. Or, someone may want to condense two enlargers into one, or scale up their negative capacity without getting a second enlarger at all, or maybe even repair a 23C head and upgrade it at the same time; there are all kinds of reasons. Even so, I can't see that this would be a large-market product, but it might help out a few people here and there. Of course, the economy of scale helps out tremendously in this kind of situation: the more kits I make, the less expensive they get per kit...but that's a bridge for another time.

That being said: if anyone else is potentially interested, please let me know. And if there are specific features that people would like to see incorporated into this conversion, please let me know that as well. In the meantime, I'll be continuing with the prototyping, which is a phrase that here means "bolting stuff together that the print-bot made for me overnight."

Pictured: Thank you, print-bot; you've done well.

[ Aside: I hate having to downsize these images to 800 pixels wide. It's killing the resolution, but I can't get anything larger than that to upload. Apologies to all.]

So, that's the first workable prototype of a three-piece bracket that bolts onto the back of the stage mounting bar, and it has a few problems...but I already knew about them so they're not a serious issue. Chief among said issues are size and shape of the small mounting tabs that hold the 23C pivot shaft; there are two #6 screws holding each one of them into the back side of the main body of the bracket - and that's more than enough, because a #6 screw will hold somewhere between 70 and 140 pounds, depending on what kind of force we're talking about - but they're only .750" apart from each other, on center: that's putting a ridiculous amount of force on a very small area of the printed bracket body. This force will almost certainly cause some deformation in the bracket when a 20-lb. head is slung from it...but for now, I'm more interested in getting this piece fitted and working well with the stage mounting bar.

Pictured: Thusly.

There are six fasteners in total that are holding this thing in place: the large 3/8-16 bolt at the top (countersunk, here), three #6-32 screws that sandwich the stage mounting bar between the bracket and the rack gear on the opposite side, and two #8-32 screws that were part of the factory mounting system for the tilt bracket, and which are now threaded into recessed hex nuts. Interestingly, the MCRX stage bar only has two holes for the tilt bracket; the MXT that I rebuilt in the past had four, if I recall correctly. The vast majority of the load is being taken by the big 3/8-16, which is the only load-bearing fastener in the factory confusion; all of the other fasteners present are basically just maintaining the attitude of the bracket in relation to the stage mounting bar; rather, they're keeping it flat. The small tombstone-shaped mounting tabs interface with the stock 23C pivot shaft; thus, they support the entire weight of the 45 head on the carriage. They're held on by two 6-32s each, threaded into captured nuts...and since a single #6 machine screw will hold between 70 and 140 pounds (depending on the load direction) I think they're more than adequate for the task at hand.

All this being said, the design is going to fail. To explain...

Even though I printed these parts on a structural setting, I think a flat bracket with no perpendicular reinforcement is just too flexible; the PETG is strong, but not strong enough. The 6-32 screws are perfectly cable of holding it flat against the stage mounting bar, and the 8-32 screws at the bottom of the bracket can do that and take some shear load as well...but even though the 6-32 screws are spaced only 3" on center, I'm willing to bet that the force being exerted by the pivot shaft tabs is still going to deform the flat bracket somewhere below their mounting points. This could probably be solved by placing the tabs higher up on the bracket, close to the 3/8-16 screw; that would basically eliminate the lever arm of the head's weight, and likely keep the deflection out of the bracket and the stage mounting bar itself. Also, yes: I have the suspicion that the stage mounting bar will bend slightly, despite being a piece of 1/4"-thick steel.

All of that, however, is a problem for a future time; right now, my main focus needs to be continuing to prove the concept by actually getting the condenser stage mounted-

Pictured: Oh...well that was anticlimactic.

I, uh...actually, I didn't think that was going to work...so, okay then! Party on? Bonus?

Nope: let's analyze things.

First of all: the lower parts of the 45 condenser and negative stages really are significantly taller than they are on the 23C. The image is a bit out of focus, but you can probably see that the 45's stage mounting bar extends quite a bit lower than the lens stage on the 23 would extend. Specifically, the distance between the pivot point and the lowest-extent of the negative stage on the 23C is about 8.5"...but on the 45 it's 17". That seems like a big increase - and it is - but I don't think it's a huge problem for most people because the lowest extent of the carriage travel on the 23C is kind of useless: at a certain point the lens stage is literally too close to the baseboard to be useful. So, I'm not exactly worried about losing that room.

Second: shown below the head (on the blue towel) is a pre-prototype bracket mockup that attempted to impose a measure of yaw prevention into the mix by widening the mounting points of the condenser, similar to the method that the 23C head uses. It was a good idea, but it was WAY too flexible, and it introduced more problems than it solved: yaw control is likely best handled by replacing the pivot shaft bracket on the 23C carriage with something more robust and adjustable, which would let the conversion bracket in question only handle the load of the head. I think that would be an improvement over the factory system, which essentially relies upon gravity and the straightness of the chassis itself to control the one axis of the vertical alignment of the head.

Lastly: exactly none of these issues are either important or solvable until the actual head of Enlarger A is test-grafted to Chassis B, because that amount of weight being added is going to provide the information necessary for the design of the conversion bracket and all of its ancillary pieces...and that's why I just decided to go ahead and send it in the hopes that a rather rash A-B grafting didn't end up destroying something important.

Pictured: Abby Normal?

It might be a mockery of nature and established convention, but that, Dear Reader, is a fully-dressed 45 condenser head suspended on the chassis of a 23C, and I'm rather happy with it being there. That being said, there's just one tiny little problem with this arrangement, and it's not the random orange plastic dingus that I'm using the prop the stage mounting bar into an approximation of perpendicularity.

Pictured: "Now pay attention, 007..."

It might not seem like a lot, but that's exactly .0055" more clearance than was present before the weight of the condenser head was added; the flat portion of the conversion bracket is flexing exactly where I suspected that it might. Thus, we now know that a redesign of the conversion bracket is absolutely needed, but even so, the test-mounting of Abby's head gave me a lot of additional and relevant information:

• It's likely that the small mounting tabs that have been used thus far will morph into stiffening rails that are the full length of the conversion bracket itself...and in addition to adding a lot of structural rigidity, this might enable multiple mounting positions for the pivot shaft.
• It's not just the bracket itself that's flexing; it's the stage mounting bar as well. There's not a huge amount of flex but it's definitely present...so a rigid bracket on the back of that bar would go a long way to solving that issue as well.
• I will likely start working with carbon-reinforced filaments very soon, because those may give the conversion bracket the stiffness it needs to remain stable and rigid under the weight of the head, as well as being strong enough to prevent the very small amount of flex that I'm seeing in the stage mounting bar. If I can't solve those issues with carbon filament construction, two further options are available: 1) moving the mounting point of the pivot shaft back up to the top of the bracket, or B) aluminum construction in one or more parts of the bracket.
• Wall projection will be difficult to achieve without making further adjustments to the head. I would have to make a new shaft for the upper negative stage adjustment knob that would relocate it to the right side of the head, and I would have to redesign the locking lever/latch of the 23C carriage to accommodate the geometry of the conversion bracket and 45 head.
• It's impossible to see in the picture of the fully-assembled 45 head on the 23C chassis, but in that image the carriage lock is fully disengaged. That is a very important piece of information because it means that the factory counterbalance springs are adequate to suspend the weight of the 45 condenser head. The carriage will also stay in place if the head is removed and only the weight of the condenser and negative stages remain, but it will all race upwards upon being bumped or jostled too severely. Movement of the carriage both upwards and downwards is smooth with the full weight of the head in place, but movement downwards is slightly easier; I think this means that the factory springs are only off by a pound or three, if that. If I design this entire thing correctly, I may not have to swap the springs out.
• At the lowest extent of the carriage travel, the lens stage is about 8.5" over the baseboard. At the highest, it's around 37.5" or so, because...wait, really? 37???

Pictured: Yes, really.

Alright...so there's room for a chassis brace at the top, if such is even needed. That's a question for Future Me, though, because I actually need to do a bit of thinking and planning before I waste too much more plastic and/or machining time. As such, I have a couple of questions for anyone that might even be remotely interested in this conversion kit, or whom wishes to contribute for any other reason:

1. How important is wall projection? As mentioned, it's not really a happening thing with the current arrangement and I, myself, will basically never use it...but I may not be the only person that's using this kind of setup in the future. I have some ideas - move the shaft, create a locking bar, move the catchment latch, etc. - but unless that's a feature that a lot of people might want, I may not make it a huge priority right now.
2. How much head/carriage travel is actually needed? Right now there's literally 29", which is over 30% more travel than the 45 chassis allows; that much travel might allow for additional chassis bracing at the top of the rails, albeit at the expense of overall height.
3. How important is a print-it-yourself version of the conversion parts? I'm a big fan of sharing info so that people can build things for themselves if they want to do so, but since any printed parts are increasingly looking like they'll be made out of filaments that have special requirements for printers (as of early 2025) this may not be a feasible thing for some folks...and since material choice absolutely drives the design, I have to think about this pretty early in the process. Also, there may be some parts that simply can't be printed at-home, so I have to think about that as well.
4. How important is back-conversion? Once the conversion parts are installed, how important is it to be able to remove them and use either the head or the chassis in their original configurations?
5. Would you be willing to drill a couple of holes? Nothing major, obvious, difficult or otherwise-problematic; just a hole or two.
6. What am I not thinking about, here? What looks perfectly obvious that I'm not seeing, so far? Let me know if something stands out.

Okay...that's pretty much the sum of it for now: Abby is hanging out in her barely-stitched-together glory and I'm working on a better way to handle the pivot shaft - maybe make the carriage the structural part, instead of the stage mounting bar..? - and vaguely realizing that all I've eaten today is coffee. So yeah, gotta go fix that. Stay tuned: it's finally getting interesting.

 

[grahamp]

I am reading this with considerable interest, as I have my own 4x5 to 8x10 conversion in play. Different approach/needs, though. Yours seems much more ambitious, but well thought out.

The old (front strut) M45 enlargers have a hook to fit over the torsion housing for horizontal projection. That went away when the later models came in - I've never used it. I have done horizontal using 35mm and medium format once or twice, but I would not miss it.

I am aiming for 20x16 prints on the (dropped) baseboard for mine. I think that's fine for my purposes, but I suppose a larger option would be nice...

FDM filament is odd. The construction in strands melted together is something only a materials science major could love I wondered which filament (easily available and printable) had the most stiffness, and from what I can dig up it may be the enhanced PLA types. Carbon fiber infused filament has a lot of strength under tension, and polycarbonate seems to do well in compression and heat. Over-designing your plate into a ']' form, possibly embedding steel rods (something I have done to reduce flex), or defining very small through holes to get extra walls through the body of the part can work.

I can't be sure from the photographs, but could you make the 3d printed part wider that the metal carriage to hold more stiffening, and is there scope for clamps to hold the part in place?

 

[Sundowner]

I am reading this with considerable interest, as I have my own 4x5 to 8x10 conversion in play. Different approach/needs, though. Yours seems much more ambitious, but well thought out.

I'm mostly just trying to think ahead on this one; by doing so, hopefully I'll come up with an elegant solution. That being said, you've made an interesting observation: if I can make a 45 head work on this chassis, I should be able to make any of the conversion parts for this head work as well. Theoretically, an 8x10 head mod could be accomplished.

The old (front strut) M45 enlargers have a hook to fit over the torsion housing for horizontal projection. That went away when the later models came in - I've never used it. I have done horizontal using 35mm and medium format once or twice, but I would not miss it.

It's present on my donor 45 chassis as well, and it's a rear-strut model...but yeah: you're correct about that. From looking over my schematics of various vintages, it seems like that hook just vanishes at some random point; the hole in the carriage is still there in the schematic, but the hook is gone. That gives me an idea, though: I could get rid of the 23's catchment lever entirely and introduce something more similar to the 45's method, and likely give it some actual adjustment and tunability. Hmmm...I'll have to think on that.

I am aiming for 20x16 prints on the (dropped) baseboard for mine. I think that's fine for my purposes, but I suppose a larger option would be nice...

What kind of elevation over the bed will you need for the next size up?

FDM filament is odd. The construction in strands melted together is something only a materials science major could love I wondered which filament (easily available and printable) had the most stiffness, and from what I can dig up it may be the enhanced PLA types. Carbon fiber infused filament has a lot of strength under tension, and polycarbonate seems to do well in compression and heat. Over-designing your plate into a ']' form, possibly embedding steel rods (something I have done to reduce flex), or defining very small through holes to get extra walls through the body of the part can work.

Yeah, it's weird stuff for sure. PPA-CF is one of the new kids on the block right now, but I'm still too much of a newbie at this to start playing with the expensive materials. PETG-CF might be an answer, though, and if that doesn't do the trick then I know some 6000-series plate will handle it. The only problem with that latter option is that I would absolutely want the accuracy of laser-cut parts, and that means I'd be making them ahead in order to purchase the rough parts in bulk for finishing in-house.

Adding some tube to the structure has occurred to me, so I'm glad to hear that I'm not off the deep end with that notion. This being said: I may go about this another way entirely. I need to do some thinking on the idea to see if I'm correct before I start cutting parts and posting pictures, but there may be a way to seriously simplify the entire thing; I just have to get creative with the carriage.

I can't be sure from the photographs, but could you make the 3d printed part wider that the metal carriage to hold more stiffening, and is there scope for clamps to hold the part in place?

Like, can I make the part wider than the stage mounting bar? Is that what you're asking? If so, sure: I just have to incorporate a spacer or some relief cuts to clear the sliding portions of the negative and lens stages. I don't know that there is room for a clamp of any sort; that would occlude the function of the surrounding parts, if I'm following your question correctly.

All that being said: I could just think on this really hard and realize that Beseler hung the entire weight of the head from one bolt. One.

 

[Sundowner]

So, I think I may be doing this backwards...

I was thinking about it yesterday/last night, and I realized that I don't have to use the factory 23 pivot shaft in its factory location; I could easily move that pivot point by placing the bulk of the mounting bracket on the carriage itself. In that scenario I could just use a single, small mounting dingus on the head, right at the top. You know; where it's supposed to mount.

Looking carefully at the 45H picture, one can see a bracket on the carriage; I'm not sure of the exact geometry, but it's very similar to what I was already thinking... except that I may try for something that maintains the pivot position where I have it, because that's kind of a nice place for it, overall. I can see that this might simplify construction and allow me to better use the structure of the carriage...so, to that end, I've decided to be smart: I found/ordered a reprint manual for the 45H and I'm going to see if I can glean any insight from Beseler directly. I won't really be able to replicate what they did on the 45H, but I may be able to either confirm or deny a revised proof of concept...and the revised concept that I'm working on is solid. It's simpler, with fewer custom parts, and more rigidity; that's an improvement all around.

I'll try to knock out some design work or prototypes here in the next few days, while I'm waiting on the manual...and on carbon filament as well. Ugh, reinventing the wheel is such a load.