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Enlarger Bulb

Pfiltz

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NW TN. USA
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Does the type of bulb you use in enlargers influence the print with regard to quality.

I understand the stronger the intensity of a bulb, will effect how you use the lens, to stop down or open up to get the proper exposure, but what about quality. Right now I have your everyday plain Jane 40 watt household light in my Beseler.
 
A plain household lamp is less effective concerning the effective light output, but this would not affect quality.

Of much importance is however the size of a lamp and the transmittance quality of the bulb proper (clear or opal), actually the latter is finally a matter of size too... At least any enlarger that employs a condenser should be fitted with a lamp of proper physical size.

In the latter case the position of the lamp is of importance too.
 
Last edited by a moderator:
Thanks AgX....

Well, I pretty much don't have any control over the positioning of the lamp. It's in the lamp housing, and it's pretty much stationary. I've got to find a lower wattage bulb though. I was making prints of a still life yesterday, and I was exposing at 5 seconds, with a 3.5 graded filter in place too.

I don't have any ND filters that I can use, so I may see if I can find a 25 watt bulb today, to help me increase my exposure times to I can dodge and burn better, or at least on this one image. I was printing on some Ilford MGIV glossy RC paper.
 
Order a sheet of nd gel, stop the lens down, don't change the bulb. Smaller wattage bulbs will have a warmer color temp, are typically smaller, won't have the heavy frosting that a real ph series bulb has.
 
Thanks Vinny.

Of course, not all my negs require max 5 seconds of exposure. This one did, because it was a really High Key type of shot, with minimal black imagery in it.

 
You want to avoid clear and frosted lamps as well as ones with writing on the side or top (depending on bulb orientation). The lamps intended for enlarger use are (generally) white and have printed ratings in a discrete location to avoid an image of the filament and/or words/logo being projected through the lens.

Note: This is for B/W enlargers that do not use halogen or dichro lamps.
 
paul_c5x4 said:
You want to avoid clear and frosted lamps as well as ones with writing on the side or top
Click to expand...

Really? Good to know, however; I'm using one bought at Walmart. One you would use in your house in a lamp. It's frosted and has print. The printing on the bulb does show up, when the condenser [Those 2 big pieces of glass] below the light lamp housing, are removed, otherwise; I don't see any printing on the board that the paper sits on.

I guess I can google enlarger bulbs to see if I can grab one somewhere.

Thanks
 
The printing on a bulb can either be taken off with solvent or with an abrasive paste.
 
AgX said:
The printing on a bulb can either be taken off with solvent or with an abrasive paste.
Click to expand...
I've had to do this with a couple of actual enlarger bulbs, in fact. One of those safe scrubby sponges (that are fine on non-stick pans) worked pretty well.

And Freestyle has a few other enlarger bulbs if you have the 45MX - that one's different. I took a guess that you had a 23C.
 

+1

Most importantly, however, the size and shape of the bulb determines, along with any reflectors in the lamp house, the shape and position of the light source. And the condensers are designed with that shape and position in mind.

If the household bulb doesn't match the shape and position, the condensers won't illuminate the negative evenly, so your prints won't print evenly.
 
Matt, regarding the size and shape of the bulb, I've just switched out the 75W bulb from an old Durst 606 enlarger into my Durst M600, replacing the 150W globe which was giving me ridiculously short exposure times, even stopped right down. I intended to run some tests anyway, but you've just given me something else to look out for. The 75W bulb is slightly smaller and narrower than the 150W. Do you think this might be much of an issue?

I have a Kodak Wratten ND .20 filter which I was intending to use but my concern with it is how stupidly hot the enlarger gets so I thought I'd try the other bulb out first.

(Apologies to the OP if I seem to be hijacking the thread but I hope any answers elicited to my question might help others also with regard to replacing bulbs... that's my excuse anyway )
 

It's the same concern.

Is the bright part of the bulb where the rest of the optics of the enlarger expect it to be?

There are tests you can do that check how even the light is, and whether all the corners of your negatives are properly illuminated. Printing a slightly fogged piece of film is one of them.

Some times you can add extra diffusion to even things out, but that changes the character of the illumination, which is one of the strengths of Durst enlargers.
 

The 600 and 601 condenser were designed for 75watt bulbs, a smaller bulb may not matter with 35mm but might with the 6X6 condenser packet. My enlager bulbs are the same size as standard household bulds, I have used GE softwhite bulbs in a pinch while waiting for enlarging bulbs in the mail. Using standard bulbs in a Durst is somewhat easier, as the light souce is not stacked on top of the condenser but is off the side so the printing on top of the bulb does not show at all. On the end of the scale I have used oversize bulbs in my D3, almost like a difussion effect.
 

Thanks, Matt, I'll keep on eye on that and check around for the best tests to do to determine if the smaller bulb is causing any problems.
 

It can be interesting if you have a large, evenly toned area. Sky? with GE 25 Watt in it. )
 


I use those crap bulbs and never had anything show up on my prints.... Maybe there was/is a bad batch out there but mine has been fine. I have a stock of those. Can you buy "name brand" bulbs made for enlargers anymore??
 
I didn't say that right.... I never had any IRREGULARITIES show up on my prints....
 
Hello !
Type, size and construction of the bulb can atter depending on the construction design of the enlarger.
As you use an enlarger with condensers, you should have a bulb large enough to light the top condenser totally and of enough power to get a decent light level on the baseboard.
Try to measure the evenness of the lighting on the baseboard to check if the bulb is large enough to cover the top condenser : put a grade 5 paper on the baseboard, and to a test strip in order to get a pale grey on the center spot of the baseboard.
Then expose a full sheet (the largest the better) at the same setting. As it is a grade 5 paper, any light ouptut variation will show.
So you'll know.
Often you can adjust the relative position of the glass of the bulb regarding the condensers. It is not clearly described in the user manual but...
My Durst enlarger was designed for 4" dia bulbs which are no longer made. In order to even the light on the baseboard, I am forced to use a very powerfull lamp and a frosted glass betwenn the bulb and condenser. I have less than a 1/3 stop difference between the center and the corners of the baseboad....
 
@George
If you have the L138 you might try a G40 lamp.
There is a thread where someone tested the G40 against the real Durst bulb, and it matched fairly well. And best of all they are easily available, and very inexpensive compared to the Durst/Thorn bulbs.
I plan to use a 60 or 100w G30 in my L1000, once I get it setup.
 
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