Beseler condenser head paint puzzler

No, I'm not talking about the exterior paint. I know that varies, and can be gray, blue or black.

I'm referring to the interior paint. I've got one that's matt black inside, and one that's all white.

These are both Beseler condenser heads -- factory painted, and not modified by a previous owner. They both are designed for P212 / P211 bulbs.

I don't have any complaints, but I never noticed this before. Maybe I should run some tests. It seems that one would be better than the other, but why are there TWO? The older one is white inside (gray on the outside). The one that's black on the inside is black on the outside (45MXII)

Any thoughts???

Most "condenser" enlargers, unless 'point source,' are all hybrids with characteristics of both diffusion and point source.

In one case the white paint in the lamphouse could improve efficiency. In the other cas, black could reduce non focused light on the negative. I suspect one wouldn't be able to tell much either way.

The black one might be intended for use with a point source.

MattKing said:

The black one might be intended for use with a point source.

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It's just a regular Beseler 45MXII condenser head. I've got two Beseler point light sources, so I know the difference. Both of the point light sources are black on the inside -- which makes sense. I just don't get why this MXII head is black as well.

xkaes said:

It's just a regular Beseler 45MXII condenser head. I've got two Beseler point light sources, so I know the difference. Both of the point light sources are black on the inside -- which makes sense. I just don't get why this MXII head is black as well.

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Maybe someone added the paint themselves.

I bought the head new with the enlarger, and it's not painted -- it's black, anodized aluminum.

FWIW my 45MX has a black finish interior.

Thanks for that. At least I know I didn't get a "screw-up".

Of course that raises the question -- Why did Beseler make the change? Was black simply cheaper than white?

xkaes said:

I bought the head new with the enlarger, and it's not painted -- it's black, anodized aluminum.

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Now, that's interesting...

xkaes said:

Of course that raises the question -- Why did Beseler make the change? Was black simply cheaper than white?

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Neither one is going to be cheap when you have to either strip or etch-prime the anodization in order to create acceptable paint adhesion, which is one of several reasons for why you usually anodize or paint; not both. That's especially true for aluminum, which has to be etched anyway in order to create a proper bond; going direct over anodization with a high-solids matte finish is be a recipe for a peeling finish. Not saying that it can't be (or isn't) done, just that I'm not seeing the benefit of them doing it in this case.

Beyond that: no idea. The anodization/paint combo is the curious part, to me. It's always going to cost more to stock more paint colors, but adding an entire second process into the mix (that then has to be worked-around) is really expensive.

My comment about the cost wasn't serious, but since another MXII condenser user has a black head too, it was intentionally done in the factory. It seems it's time for me to do some simple tests -- since I have both "colors" for comparison. I'll add it to my list. If nothing else, I would assume that the black head would reduce the amount of light going through the lens, and increase the heat of the head. I don't see the benefit of either.

I just did a quick test and as I expected, the light source with white "paint" inside is brighter than the black one -- about one f-stop. Yes, I made sure I used the same light bulb in both - a P-212.

Maybe Beseler switched to black because they were getting a kick-back from the electrical power companies.

xkaes said:

I just did a quick tests and as I expected, the light source with white "paint" inside is brighter than the black one -- about one f-stop. Yes, I made sure I used the same light bulb in both - a P-212.

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Yes, but did you use that exact same bulb in both texts, and did you check the voltage at the socket in each enlarger when connected to the exact same power source, and did you use the exact same lens in both texts? Good science demands pedantism.

I'm kidding, of course. Well, kind of, at least.

I'd say that based on your results, they possibly accepted the one-stop loss in exchange for a less-reflective interior...but that's assuming that they were having reflection issues with whatever configuration existed immediately prior. I don't really think that theory holds a lot of water, but it's all I can think of. Personally, I think matte white just works better...but I'm also not very educated in the science of this, so...

Sundowner said:

Yes, but did you use that exact same bulb in both texts,

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Actually that's a very legitimate question.

Aside from manufacturing differences when new, incandescent bulbs dim with use. Tungsten sublimes off the hot filament and condenses on the glass, and the film of deposited tungsten basically acts as an ND filter on the inside of the glass. Incidentally too, this is what eventually causes filament failure, especially since thinner parts of the filament wire tend to be hotter and lose tungsten at a faster rate(there's a side discussion here about this not happening at least to the same degree in halogen bulbs, which have a small amount of bromine or iodine present that, when hot, will scavenge tungsten off the glass lamp envelope and redeposit it on the filament provided that the temperature is high enough).

I have a 45MX but it's in storage and have to admit I don't have any recollection of the inside of the lamp housing. White SEEMS correct to me, but then I also have a 23, which I've always felt like was more or less a smaller version of the same enlarger, and I remember the lamp housings being a similar design. I haven't had my eyes on either since 2020(hoping that changes soon) so can't offer anything.

The inside of my early 90's Beseler 45xyz is black.

Ben Hutcherson said:

Actually that's a very legitimate question.

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Actually answered in Post #11.

xkaes said:

Actually answered in Post #11.

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You said you used "the same light bulb in both" but then you specified the type " - a P-212." Per my read, that simply meant that a bulb of type P-212 was used in both heads for both tests; it did not mean that you physically removed the bulb from one enlarger and used that specific, exact bulb as a known control for testing the other enlarger, although that was one possible connotation. My question was intended as humor, to make fun of the necessary pedantism of scientific testing...but thinking about the tungsten issue that was just mentioned - as well as the differences I've seen in bulbs, fresh from the package - it could be a valid concern after all.

Maybe you should also check to see if the contrast of the projected image is any higher with the black painted one. To me that would be the main reason for going to the black interior.

The later Beseler 4x5 enlargers are not as complicated as the earlier models. For instance the earlier models had machined surfaces at the negative stage, later skipped machining and use a couple pieces of rubber.
I have not had any issues with the latest versions, they work fine.

Sundowner said:

You said you used "the same light bulb in both" but then you specified the type " - a P-212." Per my read, that simply meant that a bulb of type P-212 was used in both heads for both tests; it did not mean that you physically removed the bulb from one enlarger and used that specific, exact bulb as a known control for testing the other enlarger, although that was one possible connotation. My question was intended as humor, to make fun of the necessary pedantism of scientific testing...but thinking about the tungsten issue that was just mentioned - as well as the differences I've seen in bulbs, fresh from the package - it could be a valid concern after all.

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OK, just to be perfectly clear, I used the same exact bulb in both heads -- physically removing one and placing it in the other. It's true that using said bulb in the first head might have reduced its illumination, so that in the second head the illumination was reduced. I'm betting on no significant difference -- null hypothesis.

glbeas said:

Maybe you should also check to see if the contrast of the projected image is any higher with the black painted one. To me that would be the main reason for going to the black interior.

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Anything is possible, such as your hypothesis -- or even a difference in evenness of illumination on the baseboard. Assuming the black interior gives a somewhat narrower beam of light through the condenser, it's plausible that a higher contrast / less diffused / sharper image / grainier result might be obtained.

Sounds like a whole nutha thread.