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Re: NEON- Re: color checker??
Marcus Thielen wrote:
>
> Dear Matt,
> Soda or pyrex will be transparent for 350nm UV radiation, but will
> behave like black cloth for 254nm.
> So you can never excite fluorescent powders throgh any glass except
> pure quartz. All powders are primary excited by 254nm, only some mixed
> powders may have additional phosphorescent compunds which are excited by
> the 350nm range.
>
> When I'm unsure in a broken unit's color, I light into the tube with a 244nm
> UV laser. So I can see the pure phosphor, but not the tube's color after
> been pumped. To get the right color, you have to add the grren and blue
> components of the mercury discharge. No color checker can afford this,
> some parts of the phosphors are excited by the free electrons present in the
> tube. Color checkers can only be a rough estimation.
>
> Marcus
Reply from dirk:
As always Marcus, perfect reply. BTW you mixed up a Dick and a dirk from
this list. Last reply from about Hg came from Dick (Luttin?) and not
from dirk. Only for the record my boy. From all powders I sell the
exitation wavelength is 253.7 nm and what you see there with your UVC
lamp is what we cal the FUNDAMENTAL output of the powder, you also can
give these number in a X and Y coordinate.
In a low pressure mercury discharge lamp, like noenlite is, all colours
will change to the blue part of the rainbow for about 12 % as an average
depending on the process and the quality of the tube. Vacuum is a main
part of that as well, what I mean is for the quality of the tube. So,
looking to the fundamental clours with a UVC tube you can calculate on
what wavelength the light will emit, only by studying the CIE colour
triangle. For those who are not familiar with the CIE color triangle, we
did put it on out webpage.
Go to bleacker@xs4all.nl and then to the homepage of "arturo". There you
will find the CIE colour triangle. Questions can be asked to arturo,
marcus or myself. BTW any suggestions from someone about how to finsih
our page which is still under construction. Any idea's or special
requests? like European stuff?
Pleas let me know.
Best from dirk a. boonstra
References: