Barbieri darkroom lamp

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Malcolm Stewart - 21 Nov 2004 21:13 GMT

I picked up a Barbieri Colorlamp 50 dark room lamp for next to nothing some
time ago. I've since seen it offered at around ?200. What's so special
about it? It's just a case, power supply, some amber LEDs, a colour filter
(which I needed to re-align in mine), an On-Off switch and a brightness
control.

Curious

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M Stewart
Milton Keynes, UK
http://www.megalith.freeserve.co.uk/oddimage.htm

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Jed Savage - 21 Nov 2004 22:00 GMT

The expense is probably because of LEDs - you don't need to worry about
changing the bulbs
also Brightness control is nice as you can control the darkroom light
when working with different light sensitive materials. Some of it
could be brandname as well, but I'm not really familiar with darklight
brands. I just use the little screw mount bulbs sold at my local photo
store.

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Jed Savage - 21 Nov 2004 22:01 GMT

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Malcolm Stewart - 22 Nov 2004 09:13 GMT

> The expense is probably because of LEDs - you don't need to worry about
> changing the bulbs
[quoted text clipped - 3 lines]
> brands. I just use the little screw mount bulbs sold at my local photo
> store.

But, LEDs are so cheap nowadays - and adding a potentiometer isn't a big
cost. Guess it must be the brandname and finish - it certainly looks better
than my old safelight, but then I can't see that aspect in the dark.

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M Stewart
Milton Keynes, UK
http://www.megalith.freeserve.co.uk/oddimage.htm

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Jim Phelps - 22 Nov 2004 11:38 GMT

>I picked up a Barbieri Colorlamp 50 dark room lamp for next to nothing some
> time ago. I've since seen it offered at around £200. What's so special
[quoted text clipped - 4 lines]
>
> Curious

If it's anything like the LED Durst safelight, then they are hand selected
and spectrum matched LEDs. A time consuming and expensive process where
only about 1 in 5 LEDs get used.

Not sure about the spectrum of your particular safelight, but the Durst is
'tuned' to the spectral hole shared by all papers, B&W graded & VC, Color
Neg and Color Pos. Brightness of the light is varies according to tests on
the material used It's a one safelight for all things [paper] deal.

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Malcolm Stewart - 22 Nov 2004 12:48 GMT

> If it's anything like the LED Durst safelight, then they are hand selected
> and spectrum matched LEDs. A time consuming and expensive process where
[quoted text clipped - 4 lines]
> Neg and Color Pos. Brightness of the light is varies according to tests on
> the material used It's a one safelight for all things [paper] deal.

Thanks for the info - I'd never realised that the output spectrum of LEDs
varied. I thought light output was fixed by band gap of semiconductor mix
used, and that that was tightly controlled.

I'll treat my bargain find with greater respect!

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M Stewart
Milton Keynes, UK
http://www.megalith.freeserve.co.uk/oddimage.htm

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Jim Phelps - 22 Nov 2004 16:04 GMT

> Thanks for the info - I'd never realised that the output spectrum of LEDs
> varied. I thought light output was fixed by band gap of semiconductor mix
> used, and that that was tightly controlled.
>
> I'll treat my bargain find with greater respect!

I hope you didn't misunderstand what I meant by 'tuned'. The spectrum will
vary from device to device within their tolerance due to inconsistencies in
the doping of the substrate. This spectral variance will be minor (say 5%),
but place enough of them in a device like a safelight and you get a 10%
bandwidth coverage from optimum (theoretically). That might be significant
enough to make the safelight, well, unsafe;~)

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