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Blak-Ray® B-100 AP Lamp for UV & UVIVF Photography

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#1 Andrea B.

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Posted 19 February 2015 - 16:19

Most Recent Update: 06 March 2015 15:30 GMT

Admin Note: We are going to summarize the results of several thread's worth of postings & knowledge here. It will take a while to gather up the data.

Disclaimer: Please note that UltravioletPhototography.com has no affiliation with the company UVP, LLC which manufactures and sells Blak-Ray® products nor does UltravioletPhotography.com endorse any particular products. The Blak-Ray high intensity UV lamps mentioned here are just one example such lamps. There are other companies which offer similar high output UV lamps.

Blak-Ray® Links: Blak-Ray® Spectral Charts from UVP
The x-axis shows wavelengths in nanometers. The y-axis is unlabeled but can be considered the relative spectral power of the Blak-Ray.

Attached Image: 365UV_withoutFilter.jpg

Attached Image: 365UV_withFilter.jpg

Blak-Ray® Spectral Chart by John Dowdy, Ph.D
John Dowdy of Rapid Precision Testing Laboratories has measured a filtered Blak-Ray B-100 AP donated by Damon Noe. Both are members of UltravioletPhotography.com. A big thank you to both gentlemen for their contribution to a better understanding of how this Blak-Ray lamp can be used for Ultraviolet and UV-induced Visible Fluorescence photography.

John's charts are copied here. Please see the original thread for more details. Original Thread: Blak-Ray Spectrum

The x-axis in both charts shows wavelengths in nanometers. The y-axis in the first chart shows the Blak-Ray's spectral irradiance in watts per square centimeter per nanometer, that is the radiant power of the Blak-Ray at each wavelength as measured on the surface under illumination.

The second. semi-log chart allows you to easily compare amounts of output by the Blak-Ray. Each label {10-2, 10-3, 10-4, etc.} along the y-axis represents 10 times more irradiance than the preceding label. So, for example, the amount of UV output around 365 nm is somewhat under 10*10 = 100 times more than the UV output around 330 nm. (Without the actual values at those spikes, I can't be more precise. However, it might be about 10-1.8 ~ 60 times more at 365nm than at 330nm.) The amount of UV output around 365nm is somewhat over 10*10*10 = 1000 times more than the IR output around 750nm.

Posted Image

Posted Image

Infrared Output from Blak-Ray B-100 AP
With proper filtration, not a problem for UV or UVIVF.

The semi-log version (second above) of the spectral chart made by John Dowdy shows Infrared output from the Blak-Ray B-100 AP. As noted above, the amount of UV output around 365nm is somewhat over 10*10*10 = 1000 times more than the IR output around 750nm.

Although the spectral charts posted from the manufacturer UVP do not go beyond 500 nm, this IR output mentioned in the Blak-Ray Ultraviolet Intensity Meter User Instructions: [T]he unfiltered Model B-100A 100 watt mercury vapor BLAK-RAY Lamp has an average infrared intensity of 10% of the total reading. The value decreases to an average infrared intensity of 2.6% of the total reading when the filtered longwave emission is viewed. Of course, it does not say over what interval that average was computed.

With a properly UV/IR-blocked lens, the Blak-Ray IR output should not affect UVIVF photography because the IR will not be stimulating any higher-energy emissions in the Visible range and any reflected or emitted IR would be blocked by the UV/IR filtration. Similarly, with a proper UV-Pass filter or stack on the lens, the Blak-Ray IR output should not affect UV photography.

Visible Output from Blak-Ray B-100 AP
Minor violet/blue problem for UVIVF, not for UV.

The Blak-Ray has a Visible violet spike around 405 nm typical of mercury vapor lamps. The semi-log chart shows that the amount of UV output around 365 nm is somewhat over 10*10*10 = 1000 times more than the Visible output around 405 nm. Most UVIVF done here on UltravioletPhotography.com is managed with broadband excitation and emission filters, so while there might be some reflected violet recorded during UVIVF photography it would seem not to be enough to overwhelm any strong fluorescence. Narrowband filters should be used whenever specific photographs are needed of fluorescence in the Visible violet or blue region.

With a proper UV-Pass filter or stack on the lens, the Blak-Ray Visible output should not affect UV photography.

Lens Filters for UVIVF
For generic wideband emission, wideband excitation UVIVF photography, the Baader UV/IR-Cut filter is a good choice for passing visible light. To block unwanted violet/blue leak try stacking with a Schott GG420 or a Kodak/Wratten 2E (415nm). Of course if you are looking for violet/blue fluorescence, then you will have to look for specialized narrowband filters.

Mercury Arc Replacement Bulb for Blak-Ray B-100 AP

Osram Sylvania H44GS-100 Mercury Reflector
This is a 100 watt mercury arc lamp for use in a Blak-Ray B-100 AP.
The chart shows visible output of the unfiltered bulb. It's got quite a green spike.
Attached Image: SPD MB.jpg

Sylvania H44GS-100MDSKSP-Medium 100W Mercury Spot R
This seems to be the same bulb. Here the chart includes the UV output as well as the visible output of the unfiltered bulb.
Attached Image: bulbh44gs100uvchart.gif

Shiny Metal Test in UVIVF Photography
from Shane Elen

Capturing fluorescence (spectrally or photographically) works on the principle that the combined effect of the excitation and emission filters allows only fluorescence emission to reach the camera sensor. Excitation wavelengths from the excitation illumination must be totally excluded. Typically very narrowband filtration is used in laboratory fluorescence photography. Here on UltravioletPhotography.com most fluorescence photography makes use of rather broadband filtration because narrowband photographic filters are not readily available.

For UV-induced Visible Fluorescence photography, the UV illumination must be filtered for UV-only output, and the lens must filtered for Visible-only input. To test that the filtration is working properly, photograph some shiny ball bearings or a shiny spoon (which are non-fluorescent, of course) in total darkness. If the filtration is working properly, then the ball bearing is not visible. If the ball bearing is visible (shows a shiny reflection), then there is leakage in the filtration which must be remedied in order to claim proper UVIVF photography.

I don't have a statement to make at this time about whether the length of the exposure time might mitigate the effects of any unwanted stray light output from the UV illumination source.

When using a broadband camera or a camera with a weak internal filter, it might be difficult to determine whether filtration leakage in the Shiny Metal Test is from stray Visible or Infrared output from the UV illumination source or whether it is from some UV getting through a mediocre UV/IR-blocker filter on the lens. Further tests using additional filtration might be useful to sort this out.

This thread contains two filtration leakage tests using shiny spoons.
http://www.ultraviol...ivf-photogaphy/

This thread contains four filtration leakage tests - two using shiny spoons and two using white reflectance standards.
http://www.ultraviol...visible-output/

Other Links
UV Systems https://uvsystems.com/index.php
Solarization of Short-Wave Filters https://uvsystems.co...LAR_8_31_90.pdf
Life of Short-Wave Filters https://uvsystems.co...ation_Lamps.pdf
Company Seven http://www.company7....highintens.html
Andrea G. Blum
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#2 colinbm

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Posted 19 February 2015 - 23:04

Good thread Andrea.
I hope UVProducts are able to provide the data on their Blak-Ray B-100 lamps & filter.
What we will then be needing is the data on the ageing effects &/or solarization of the filter.

Another supplier of UV lamps, UV Systems Inc, https://uvsystems.com/index.php
Useful data from this company, https://uvsystems.co...echarticles.php
Solarization, https://uvsystems.co...LAR_8_31_90.pdf
https://uvsystems.co...ation_Lamps.pdf

Col

Edited by colinbm, 19 February 2015 - 23:13.


#3 Damon

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Posted 20 February 2015 - 01:37

An informative and reliable site I looked at a lot when investigating these lamps:

http://www.company7....highintens.html

Just found spectral charts for the Blak-Rays: Scroll down
http://www.company7..../uvp/notes.html

But get this--the only one they posted incorrectly is I think the one we need.

#4 Andrea B.

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Posted 02 March 2015 - 23:07

Bumpity-bump.

Please let me know of any corrections to be made, any typos to be fixed, any additions needed and so forth !!!

THANKS !!
Andrea G. Blum
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#5 JCDowdy

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Posted 04 March 2015 - 02:53

I calculated that the area under the curve of the secondary 698-800nm band is 0.90% of the area under the curve from 250-400nm. However this is not all of the NIR a CMOS sensor can detect.

I still need to measure this lamp from 800 to at least 1100 or 1200nm to cover the full Si response range. The >698 output may increase an additional percent relative to the UV.

I also plan to repeat this measurement with some filters installed in the aperture of the integrating sphere, but that will have to wait for some available time.

#6 Andrea B.

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Posted 04 March 2015 - 14:49

I don't know if we even know whether we can record out at 1100-1200 nm? "-)

I can't remember the last time I ever heard anyone refer to the 'area under the curve' since teaching my last calculus class - which was years & years ago!

**********

Most important for this write-up I'm looking for confirmation of my conclusions above:
  • For typical, wideband, non-laboratory UV photography the Blak-Ray Vis/IR output will not be a problem under proper filtration.
  • For typical, wideband, non-laboratory UVIVF photography the Blak-Ray Vis/IR output will not be a problem under proper filtration except for a small amount of reflected violet/blue.

Andrea G. Blum
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#7 Damon

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Posted 05 March 2015 - 23:54

Thank you so much for this.
Is there anything I can do?

-D

#8 Andrea B.

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Posted 06 March 2015 - 00:25

Keep on shootin'...... :D
Andrea G. Blum
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#9 nfoto

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Posted 06 March 2015 - 08:21

"For typical, wideband, non-laboratory UVIVF photography the Blak-Ray Vis/IR output will not be a problem under proper filtration except for a small amount of reflected violet/blue"

Add a Kodak 2E or similar (light straw-coloured) filter to the lens, and the small amount of violet/blue vanishes.
Bjørn Birna Rørslett

#10 JCDowdy

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Posted 06 March 2015 - 14:40

While I have not yet made the definitive spectral irradiance measurement of the Black-Ray with the Baader UV-IR cut filter, I could not agree more with Bjørn. Examination of filter transmission spectra suggest a Baader UV/IR-Cut/L would not be expected to fully block the blue emission from the Blak-Ray.

The 50% cut-off of Kodak 2E is ~430nm is cutting ~20nm off the blue passing a Baader UV/IR-Cut. I was thinking a Schott GG420 or GG435 or Hoya L-42 which should be similar.

Such a filter stacked with an ~2mm Schott S8612 or BG39 might also do a better job of suppressing the secondary >690nm band.

#11 Andrea B.

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Posted 06 March 2015 - 15:18

Add a Kodak 2E or similar (light straw-coloured) filter to the lens, and the small amount of violet/blue vanishes.

This would work for any non-violet visible fluorescence. But if the visible fluorescence is violet there is no remedy.

I will add a filter section to the write-up.
DONE: added mention of Schott GG420 from Col and Kodak/Wratten 2E from Bjørn.
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#12 JCDowdy

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Posted 06 March 2015 - 16:34

".....if you are looking for violet/blue fluorescence, then you will have to look for specialized narrowband filters."

A narrowband violet/blue filter on the camera would still see both reflected violet/blue and violet/blue fluorescence.

Correction:
....if you are looking for violet/blue fluorescence, then you will have to add a barrier filter to block that violet/blue component from the Blak-Ray excitation spectrum from reaching your subject.

#13 Andrea B.

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Posted 06 March 2015 - 22:09

Yep.
Unfortunately, I don't have any actual examples to illustrate this point that I'm constantly "nagging" about (as per my most excellent teacher about fluorescence, Shane Elen - and as per some pointers from Vivek Iyer) that both excitation and emission filtration must be dealt with - particularly for specialized cases. To use the Blak-Ray as a more specialized fluorescence induction tool might not be possible because it wouldn't be easy to filter that lamp. Although no doubt somewhere such filters exist or could be made.
Andrea G. Blum
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