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Old 10th June 2021, 09:37 AM
John King John King is offline
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Default Definitive Values

Try as I may I cannot get an accurate figure for the colour temperature of a bulb used in a B&W condenser enlarger. It seems that it can be anything from 2800 to 3500 degrees Kelvin Has anyone else any closer estimates please. I should know this but I cannot find from where.
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Old 10th June 2021, 11:29 AM
mpirie mpirie is offline
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Any sign of the colour temperature stamped on the crown of the bulb itself? Or any other identifiers?

Presumably it's a coated Opal lamp with a tungsten filament?

Mike
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Old 10th June 2021, 11:32 AM
John King John King is offline
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I actually have not got one to check, I was hoping that someone could tell me.
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Old 10th June 2021, 01:05 PM
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MartyNL MartyNL is offline
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I don't know if this will help but I use Dr. Fischer and they're rated at 2800k.
Attached Files
File Type: pdf Dr.FS-146.pdf (90.2 KB, 394 views)
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Old 11th June 2021, 09:18 AM
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Martin Aislabie Martin Aislabie is offline
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A standard tungsten bulb has a colour temp of 2800 K.

Halogen bulbs are 3200 K.

Of course their colour temperature can be changed by tinting of the bulbs glass.

The tungsten bulbs used in B&W enlargers are special only in the fact that they are made to tighter tolerances than standard household bulbs.

Martin
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Old 11th June 2021, 09:59 AM
Nat Polton Nat Polton is offline
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John.

Ollingers site has quite a few enlarger reviews, and if you click on the pdf icon on the first page it will give you access to a list of manuals for enlargers, camera, cine etc.
Just a chance that if your enlarger is in the list it may have the lamp information amongst the specifications.

http://www.jollinger.com/photo/enlargers/durst.html


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Old 11th June 2021, 10:41 AM
Nat Polton Nat Polton is offline
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I just looked at a random enlarger on Ollingers manuals list,

VIVITAR V1 enlarger PH111A bulb.

Could be a special bulb as it works on its side, but it appears to be tungsten and working in a condenser enlarger.

Looking at a bulb sellers specification it says,

PH11A 75w, 115-125v, 2900K, 1120 lumens 15 hours.

So the bit I concentrated on is "condenser enlarger" ...."2900K."


If you trawl through a couple of other manuals on the list you may find your enlarger or something similar. for confirmation.


Before I knew about colour temperature etc. i used to buy whatever bulb Woolworths had in stock and rub off the printing with a Brillo pad pan scourer.
Simple happy days.

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Old 13th June 2021, 04:58 PM
JOReynolds JOReynolds is offline
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I used to work in the lighting industry and I searched published literature in vain for the colour temperature of typical enlarger lamps.
Basically, the lifespan of a tungsten filament in an evacuated globe is defined by the temperature at which it is operated. I learned that domestic lamps would last 1000 hours at 2900K, 275W 'Photoflood' lamps would last 10 hours at 3400K. But I also found that several manufacturers quoted the lifespan of 75W and 150W enlarger lamps as 100 hours. Then I searched for other tungsten-filament lamps with quoted 100 hour lifespans. and found the bulbs used in 'studio lamps', typically 250W, 500W and 1000W, all of which have a colour temperature of 3200K. From the 1960s onward Eastman Kodak gave suggested exposure times for Ektachrome type 'L' sheetfilm and a colour temperature of 3200K.
So I reckon that enlarger lamps from Philips, Osram &co run at 3200K.
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Old 13th June 2021, 05:05 PM
JOReynolds JOReynolds is offline
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I've just read the file Dr.FS-146.pdf from Marty NL, which I had not studied and which gives a figure of 2800K. But with a remarkably short filament life.
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Old 13th June 2021, 06:02 PM
John King John King is offline
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I suppose the most accurate way is to use a colour temperature meter and see what they say. I cannot say I have ever used or even seen one.
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