New lamp in my enlarger

CCOS · Oct 16, 2008

I got a Jobo C6600 color enlarger, but the lamp needs to "warm" up before it is white, starts in a yellow color.
Lookin for a new lamp a wonder if i can get any normal halogen lamp thats fit? or shoud I get a speciel lamp for it? it a 12v 100w type A1/231 in the enlarger.

Jesper

Bob F. · Oct 16, 2008

Someone with more practical experience may contradict me but it sounds like that lamp is on its way out. I think you should get the correct lamp: others may not have the correct colour temperature and may not withstand the high temperatures of an enclosed enlarger head.

CCOS · Oct 16, 2008

Hi Bob, the lamp is used in many lightsystems for medicine/lab and stageligting, so I don't think is on the way out. Found it to ½ the price the the photo dealers wanted for it.

Jesper

srs5694 · Oct 16, 2008

I believe Bob is saying that your specific lamp is on its last legs, not that the product is on the verge of being discontinued.

It's my understanding that many bulbs do change color and brightess a bit as they warm up. This effect is most notable for fluorescent bulbs, but IIRC it's also an issue with ordinary tungsten bulbs (the sort commonly used in household lighting and in some enlargers), although it's much less of a problem for tungsten than for fluorescent bulbs. IIRC, halogen bulbs suffer from this issue relatively little, and many enlargers use halogen bulbs. I don't know offhand what type of bulb the Jobo C6600 enlarger uses, but if you're having problems with this, a new bulb is certainly worth trying.

CCOS · Oct 16, 2008

The type of the Jobo C6600 is a 12v 100w type A1/231 and it's surely getting yellow so thats a new one....

Jesper

Bob F. · Oct 16, 2008

srs5694 said:
I believe Bob is saying that your specific lamp is on its last legs, not that the product is on the verge of being discontinued.

Yes indeed. It occurred to me that there may be another reason for the lamp taking time to reach full brightness, such as problems with the voltage stabiliser if there is one.

Nicholas Lindan · Oct 16, 2008

CCOS said:
the lamp needs to "warm" up before it is white, starts in a yellow color ... 12v 100w type A1/231

How long is this warm-up period? If it is longer than 1/8 second or so then something else besides the lamp is busted.

The socket/lamp holder is the usual guilty party, however this usually shows up as erratic operation. If the warm-up anomaly always happens in the same way then the problem is probably the voltage regulator, as mentioned.

CCOS · Oct 17, 2008

The transformer deliver 12.3v stable that you mean with the voltage reg.?

New lamp in my enlarger

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