Ilford Multigrade filter with Quartz Halogen lamp

[banandrew]

Apologies if this has been answered before, but I searched and couldn't find it in the forum...

I have just acquired a Saunders LPL 670 dxl with dichroic head that's been modified to have the colour filters removed. Basically it's like having the "white" switch on the entire time. The colour of the lamp light (I think it's quartz-halogen) is different than that of a tungsten bulb. The previous owner used it as a diffused light source with Ilford Multigrade filters.

Does anyone have any experience with this type of setup? How much will the lamp colour change affect the filtering on multigrade paper?

 

[banandrew]

Well alright, doing a little sleuthing and I've learned that the Quartz Halogen is really just a tungsten filament running at a higher temperature than regular tungsten. And according to the Ilford multigrade pdf, they are designed to work with both tungsten and Halogen bulbs, so I guess it'll be fine!

 

[MattKing]

I was going to give you that answer, but was scared away by the second part of your question!
Being different from tungsten, they do give different light, so you will see a difference. I can't quantify the difference (thus the fear ) but it is totally controllable.

 

[banandrew]

Haha thanks Matt. It's not so straightforward to totally quantify it, since the tungsten setup I had used a condenser, and this halogen uses a diffuser box.

I just had a mini printing session, and have only tried a #2 filter so far, but right now it looks like contact printing gives roughly similar contrasts between the tungsten/halogen (condenser/diffuser), but when enlarging, the tungsten (condenser) #2 filter gives significantly more contrast than the contacts, however the halogen (diffuser) seems to give contrast similar to the contacts. Also, I think I am starting to understand why people like diffused printing heads so much...

 

[bernard_L]

Enlarger lamps are not ordinary tungsten lamps. I believe they run at a higher temperature and are close to halogen as concerns color temperature. The worst that might happen is a slight shift in the grade scale; the kind that might be just noticeable if you made a repeat of a print from your notes with the "other" lamp.

 

[banandrew]

Interesting, my quick tests seem to corroborate what you're saying. The reason for the post was I was a bit worried when I turned on both lamps, no filters, my girlfriend said the condenser/tungsten light was much more yellow, while the diffuser/halogen had a big green component. (I'm a bit colour blind so I don't trust myself to evaluate these things). I'll have to see at the #00 and the #5 ends if I get there eventually, but my feeling now is that if the #2 is so similar, I doubt the other ones would be too far off either

 

[John Koehrer]

As a GENERAL rule of thumb tungsten are 3200k and halogen 3400k.

 

[AgX]

There are two types of halogen lamps. Running at 3200K and when overrated by design, at 3400K.

75W non-halogen lamps at household grade run at 2800K. But being overated as the ones used in enlargers they should run at 3200K. However data sheets state only 2800. Which means that the coating has a warming effect...


But as many enlargers are run overrated by now, the lamps then are over-overrated, making these figures useless anyway...