Floral Variety in Many Wave Lengths

[Andy Perrin]

JMC did some flower and vase pics at the link below. Obviously we do not know the type of glass or thickness, but in his case no light came through the vase (for what that is worth):

https://jmcscientificconsulting.com/uvc-photography-at-254nm-colour-images/

[Lou Jost]

2 hours ago, Andy Perrin said:

JMC did some flower and vase pics at the link below. Obviously we do not know the type of glass or thickness, but in his case no light came through the vase (for what that is worth):

https://jmcscientificconsulting.com/uvc-photography-at-254nm-colour-images/

Mine also show complete opacity at 254nm, but some translucency at 313nm (ignore the label). The thing in the cup is aluminum foil:

[Stefano]

The filter used by Lou is this one, if I am not mistaken: https://www.edmundoptics.com/p/254nm-cwl-40nm-fwhm-50mm-mounted-diameter/22543/. Here's the original topic, where the filters were specified.

 

>20% minimum transmission, 30% typical according to the graph and OD 4+ blocking up to 10 μm. OD 4 is not extremely high, and the filter appears to have some transmission at 313 nm, where there's another strong mercury line, but he was successful based on his images.

 

Edmund Optics has another 254 nm filter: https://www.edmundoptics.com/p/254nm-cwl-50mm-dia-hard-coated-od-4-10nm-bandpass-filter/40056/

 

≥50% transmission, OD 4 up to 650 nm (judging from the graph, there's probably good blocking even after that, for a bit at least), and the 10 nm bandwidth isolates the 254 nm line.

 

Stacking these filters gives ≥10% transmission, with a probable typical value around 15%, OD 8 or better up to 650 nm, and at least OD 4 (probably somewhat higher) from 650 nm to 10 μm, with a narrow 10 nm bandpass. This might be the most reasonable filter for UVC, which Lukas is trying to find.

 

The difference between 100% and 15% transmission is 2.737 stops, about the same difference between f/4.5 and f/11.6.

[colinbm]

@Stefano Thank you
The filter that is supplied with the 255nm LED lights is ZWB3.
The filter that I used on the Lens is a Asahi ZUS0325......

https://www.asahi-spectra.com/opticalfilters/detail.asp?key=ZUS0325

[Stefano]

The combination of Asahi ZUS0325 and ZWB3 blocks UVA and visible light only, potentially allowing UVB, some violet, deep red and infrared (Asahi spectra only provides transmission up to 450 nm, we don't know what happens in IR, you can check that with a camera or a spectrometer).

 

If the subject has significant fluorescence in those wavelength bands, or there are other sources of contamination, the image will show that. I don't know how realistic that is, perhaps most things don't fluoresce enough to affect the image, but I wouldn't be 100% sure.

[colinbm]

@Stefano Thanks
The spectroscope says there is no leaks.
The quartz grating says there is a leak at 380-390nm or so ?
The quartz grating + ZUS0325 there is no leak.

[Stefano]

25 minutes ago, colinbm said:

@Stefano Thanks
The spectroscope says there is no leaks.
The quartz grating says there is a leak at 380-390nm or so ?
The quartz grating + ZUS0325 there is no leak.

What are these leaks referred to? Are they about the glass vase or the filtered LEDs?

[colinbm]

@Stefano Sorry.
I was testing the 255nm LED lights.
The spectroscope says there is no leaks. 
The quartz grating says there is a leak at 380-390nm or so ?
The quartz grating + ZUS0325 there is no leak.