Enlarger Bulbs?

[bill williams]

I recently purchased a PH212 from a local photo supply store. Right away I notice that the labeling for the bulb was directly on the business end, right in the plane of focus. I pointed it out to the dealer who was as shocked as I was. The bulb is made by Sylvania. Some scotchbrite and a bit of labor almost made it practical to use, so to finish it off and make it entirely satisfactory, I used some armour etch. However, then a new problem. All of my old PH212 bulbs were 4 1/4 inches in length from end to end. The new Sylvania bulb is 5 inches. This puts it further into the cone of focus, and I believe gives more fall off of light at the edges of the image. I ordered a USHIO PH212 from Freestyle and it also is 5 inches in length end to end. I suppose that all PH212 bulbs will now be too long to be direct substitutes for the old bulbs. Has anyone else using a PH212 noticed the difference, either in bulb length, or fall off, or both? My enlarger is a Beseler 45M. I suppose I can make an adapter to put the socket assembly 3/4 of an inch higher to pull the bulb back into the right focus plane.

 

[mike c]

Just replaced the bulb in my d2 omega but did not look at the size,hope it does not have writing on the top.

Mike

 

[fschifano]

So what's the problem with the different length, especially since you have the Beseler 45? The distance between the lamphouse and the negative stage is adjustable on that machine, so simply adjust it if you're not getting even lighting across the negative. The Omega lamphouse is different, but it probably has a provision for adjusting the position of the lamp. As for the printing on the "business end" of the bulb, do make sure that it's really a PH212 and that someone didn't swap it out for a plain 150 watt light bulb. I've never seen an enlarging lamp with printing on the business end. I can't see it making it out of the factory if it was a manufacturing mistake. Call me cynical if you like, but I thing you've been had.

 

[jmcd]

For years all the bulbs I have been buying are 5 inches long. But I would love a short-neck bulb for my Valoy II.

 

[bill williams]

fSchifano, the distance between the lamp and the top(first) condenser on the Beseler 45M is fixed. Adjusting the negative stage will not change the amount of the bulb focused by the first condenser. AND, it makes a difference. I'm not sure about the designation, but I think the true PH212 should be in a A12 envelope. What is now being sold as a photo bulb 212 isn't a true PH212, but clearly was marked as such by Sylvania. And the one from Freestyle is clearly marked as a PH212, but is not in the same size envelope that the true PH212 should be in however it did have the stamping in the right place, that is along the neck of the bulb. No doubt the manufacturers are trying to do away with the size bulb needed for the PH212 and substitute a more common bulb size for the PH212. Making a spacer for raising the lamp socket assembly will allow the bulb to be more properly focused by the top condenser, and allow for more even lighting. For a bulb with the designation stamped right on the business end, scotchbrite will for the most part get rid of it. Taking it a step further, some armour etch will frost the bulb and get rid of any residual writing on the bulb. And, in fact, carrying it one more step further, if you purchase an ordinary 150 watt bulb, scotchbrite the stamping off of the end, AND, use a liberal amount of armour etch evenly on the bulb, you then have a bulb which cost far less than the enlarger bulb, and is for all intent and purpose an enlarger bulb with the exception that it too is 5 inches in length instead of 4 1/4 inches.

 

[jmcd]

Bill,

I am glad you started this thread. The 5" bulbs (4-15/16") I have been getting are the Eiko brand from Freestyle. I did not know that 4-1/2" bulb used to be the standard.

I definitely get a little light falloff in the corners of my prints, and usually correct this with burning during printing.

Good idea on making the spacer collar for the Beseler. I am going to try it out.

The same idea should work for the Valoy ii. I know there used to be a short-neck bulb for this enlarger, but do not know its overall length—anybody?

As for using a regular bulb, I think that enlarger bulbs have a thicker white coating for more even diffusion—is this correct?

 

[bill williams]

enlarger bulbs do have a thicker coating, and of course its inside the bulb and you can't change that. BUT, I've used armour etch to etch the outside of the bulb and that will increase the diffusion. I have used armour etch in the past to make 'ground glass' for an old 5x7 camera and discovered that etching an ordinary 150 or 200 watt bulb with it would make it more suitable for an enlarger bulb, only you are still left to contend with the length of the bulb. The spacer is the only way I can come up with to get the proper amount of focused bulb onto the negative when the enlarger is set for the proper size negative being projected.

 

[Mark Fisher]

FYI -- the writing comes off with isopropyl alcohol.....at least it did for me.

 

[bill williams]

Thanks Mark, I'll try that on a couple of bulbs and see what happens. I know that in the past I've tried isopropyl alcohol and MEK, and neither worked. Maybe I should have let the bulb soak in it a few minutes. Or maybe different manufactures mark with different inks. I'll definitely try alcohol again.

 

[jmcd]

I have found information that one older enlarger bulb that was 4.68" long—not sure of the exact reference details.

 

[fschifano]

...further, if you purchase an ordinary 150 watt bulb, scotchbrite the stamping off of the end, AND, use a liberal amount of armour etch evenly on the bulb, you then have a bulb which cost far less than the enlarger bulb, and is for all intent and purpose an enlarger bulb with the exception that it too is 5 inches in length instead of 4 1/4 inches.

No you don't. For starters, the color temperature is wrong and that will play hell with your variable contrast filters and paper. All of a sudden you'll be wondering why are all my prints so flat looking? The normal household incandescent lamp runs at about 2700 to 2800 K. A tungsten enlarging lamp runs at 3050K, considerably hotter and more white, and guess what, all the VC filters and papers are designed to work as specified under that kind of light source. If that's not enough, the filament in an enlarging lamp is arranged differently to provide for more even illumination in the specified application. And yes, with the Beseler, you can just crank down the distance between the lamp house and the negative to spread the light out over a wider area. Using it for smaller negatives is no problem. I doubt you'd have a problem with the maximum size too. I have one of these Beseler 45's and a 5 in. lamp, and I have no problem at all with it. The bulb itself emits a diffuse light, so the position of the lamp really isn't all that critical.

 

[bill williams]

The 4x5 position of the negative stage is as far as it goes in that direction. If you are working with 6x9 or smaller negatives, yes you can make the light a bit more even. I'm working with 4x5 negatives, you can't go further in that direction. But you don't understand the workings of the condenser system and how it is set up to focus on the lamp, so maybe you could find a book on that too. You are right about the color temperature. But guess what, filter packs are adjustable. I could refer you to a couple of books that might help you. I'm sure you are right about the vc filters, but guess what, that is workable too, and I have a piece of glass that is in place for preventing heat to the filters. And you are right about the filament of the lamp and now you are getting to the point of the original post, and they aren't making the lamps the way they used to. I'm glad you helped me out on this. Thanks Frank.

 

[bill williams]

I might also add that my M45 and I suppose others have a 'resistrol' or similar unit which allows you to change the voltage to the lamp. This in itself will change the color temperature of the light emitted by the lamp. As I said, the filter packs are adjustable, you change the filter make up to adjust for lamp changes and for paper characteristics. And, if you own a set of under the lens or over the negative vc filters, you can use them in an enlarger that has either an incandescent or halogen lamp, and they will work with both. They behave a bit differently, but then if you've ever read Steve Anchell's book 'The Variable Contrast Printing Manual', you should understand that vc papers, enlargers, and vc filters are very versatile, but not consistently predictable.

I've substituted the household bulb in my M45 and besides its shortcomings in falloff, and color temperature, it will certainly work and I've printed both color and b&w with the bulb with the appropriate filters in place. It is quite capable as a substitute until a proper bulb can be secured, especially if you 'frost' it first with armour etch. I've tried about 8 or 10 different types of no-photo bulbs in the enlarger, and almost every one of them fail without some type of modification, and even then they leave a lot to desire. But a regular old 150 or 200 watt sylvania bulb with some treatment does become More suitable. Not perfectly suitable, just more suitable.

One other thing, I've been a broadcast television engineer for 45 years, and I've been working with color cameras and equipment for TV for just that long. I'm quite familiar with color temperature, color balance, photo bulbs, studio bulbs.

 

[lajolla]

The finest PHP212 3050K 150W enlarger bulbs were once manufactured by GE. But of course GE no longer manufactures any of these types of incandescents. I have found a replacement in the Osram PH212 3050K 150W enlarger bulb, manufactured for Osram in China. This bulb is nearly a dead-ringer for the old GE PHP212, and is available at www.bulbman.com

 

[jmcd]

lajolla: I have found a replacement in the Osram PH212 3050K 150W enlarger bulb, manufactured for Osram in China.

Interesting, it says it is made by Osram-Sylvania, with a length of 4.72 inches.

 

[lajolla]

This is a no-brainer. The Classic GE PHP 212 150 W 3050 Kelvin incandescent is the same as the Chinese Osram 212 150w 3050K 118v bulb. Same dimensions, and almost identical color temps. Try it out.