Re: solux bulbs
Re: solux bulbs
- Subject: Re: solux bulbs
- From: Roger Breton <email@hidden>
- Date: Wed, 13 Aug 2003 11:08:39 -0400
Graeme Gill wrote:
>
> Note that these are not "D50" bulbs, they are "D50 white point" bulbs.
>
> D50 is a specific spectrum, and these fluorescent bulbs do not
>
> produce a D50 spectrum (a source of problems, since default instrument
>
> XYZ values often use a D50 illuminant spectrum.)
>
>
To which Jim rich replied:
>
It is my understanding that the Solux bulbs that have been discussed here
>
are rated at 4700 kelvin and produce a color spectrum that is smoother and
>
less spikier than a fluoresant bulb. That seems to be a selling point.
Guys,
I have many times measured the spectrum of the so-called 'rated 4700K' with
my SpectroCam in Lux meter mode. I also measured its CCT with my trusted
Minolta Chroma meter and both instrument tell me that these bulbs do not
read 4700K as rated by the manufacturer. I get more like 4200 to 4400K.
(Bear in mind that I am not using the bulb in a black anodized desktop Solux
lamp but in a 12V halogen housing that I have manually painted in matte
black myself -- the desktop lamp was out of stock at the time I ordered the
bulbs). But, the interesting thing about the 4700K lamp is its spectral
distribution which ressembles Illuminant A with a gradual bent towards the
red end of the spectrum. In effect, Eiko has thrown in a tuned blue filter
on top of the bulb (clearly visible when you look at it) that gradually
absorbs radiation as we're moving towards longer wavelengths, thereby
decreasing the warm look of the light produced by the otherwise quartz
halogen filament. The Solux lamp is NOT a D50 simulator. I have installed
three of these 4700K bulbs in my studio that I now use for lighting at night
time, and I have to say that the 'color' of the light produced by these
bulbs takes some getting used to as it appears somewhat artificial.
Until I can ascertain why I don't get true 4700K CCT with this bulb I won't
use it for critical color proofing. To that end, I still use my trusted GTI
D5000 Transparency/Print Viewer.
Regards,
Roger Breton | Laval, Canada | email@hidden
http://pages.infinit.net/graxx
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