Blackest Black Glass & Water

[colinbm]

Blackest Black Glass & Water.

I am sure I have got it right this time.
Subject is a plain glass of water with UVC Aluminium strip in front of a PTFE background.

Sigma fp Mono converted, UV Nikkor 105mm lens with Asahi ZUSO325 filter, 255nm LED light.
First photo is in White light LED.
Second photo is in 255nm LED.

 

White light LED.

 

255nm LED with Asahi ZUSO325 filter on camera.

[Andy Perrin]

Yes that looks right in line with the previous pictures we have at 255nm now. 
 

I guess now let’s see more objects in both vis, UV-A,and UV-C. The more we know about differences between UV-A and UV-C, the easier it will become to vet future setups. Plus it’s always interesting to see what changes.  

[Stefano]

Not to be annoying, but I can still see the aluminum strip through the glass at 255 nm. How much that matters, depends on what you are after.

 

I agree with Andy, let's see various subjects at various wavelengths.

[Andy Perrin]

Stefano, yeah, but like, the amount showing is really small, and we aren't trying to do something for publication. If there's like a tiny leak somewhere it's probably "good enough" to call it mostly 255nm. If colin wants to go further to plug the last little bit that's good, but I'm fine with this for forum purposes anyway. In the case of Lou and Jonathan, they probably DO want to publish, so it is more critical to get everything right.

 

To me the biggest question is, "can we see a difference from UV-A" and how does that play out for various substances? This is probably a good enough setup to answer that.

[Stefano]

Yes, I agree it's not critical and it's enough to see how things look like in UVC.

 

I would do UVA-UVB-UVC comparisons, with the light sources placed in the same place every time.

 

Having consistent illumination is important if one wants to be able to overlay the images and not have color fringing in the shadows etc. Also it is better to reduce angle-dependent changes, especially if you want to do a comparison.

[dabateman]

1 hour ago, Andy Perrin said:

Stefano, yeah, but like, the amount showing is really small, and we aren't trying to do something for publication. If there's like a tiny leak somewhere it's probably "good enough" to call it mostly 255nm. If colin wants to go further to plug the last little bit that's good, but I'm fine with this for forum purposes anyway. In the case of Lou and Jonathan, they probably DO want to publish, so it is more critical to get everything right.

 

To me the biggest question is, "can we see a difference from UV-A" and how does that play out for various substances? This is probably a good enough setup to answer that.

Yes mostly dark. Hasn't been too exciting in UVC.

I now have everything setup again. 

I will have to take some images with my cameras.

Then Colin and I can compare as we both have monochrome UVC cameras.

[Andy Perrin]

It might be interesting to compare liquids (water, alcohol, acetone etc.). Does water go dark again? And maybe sugar/salt/other visible-white crystaline materials. Also things that show different fluorescence across UV bands may also show different reflectances. 

[colinbm]

@dabateman fantastic, I'll love having someone to pace with thanks.
Thanks everyone for the comments.