Alabaster White Balance

[colinbm]

I have now some Alabaster, Selenite, Gypsum, call it what you may....

For discussion on its use as a White Balance Tool ?

 

Three photos, please forgive the carpet inside the camera / lens

 

First is the a visible light of the Alabaster egg on top of a, switched off, light.

 

 

 

Second is with a visible light camera of an Alabaster egg on top of a lit 365nm LED light.

 

 

 

Third is with a full spectrum camera with a Quartz lens, of an Alabaster egg on top of a lit 365nm LED light.

 

[Fandyus]

What kinda flashlight is that? It's not the Nemo is it?

[colinbm]

What kinda flashlight is that? It's not the Nemo is it?

 

It's a big mother...

Alonefire H42UV

[Andy Perrin]

Wow, that is quite a torch.

 

The egg fluorescences blue?

 

[colinbm]

I am hoping the Alabaster egg doesn't fluoresce.

I need to test it more with suggestions ?

[photoni]

It's a big mother...

Alonefire H42UV

 

just today...

i was looking at these ...

just looking :)

[Andrea B.]

That seems like a nice torch kit, although a bit pricey.

*****

 

Col, it would be cool if you would please make a visible photo of the alabaster egg for which you shined the torch on it in the dark from about a foot away so we could check for fluorescence also that way.

 

There is a nice mineral shop here in Santa Fe. I'm thinking I will go over there with one of my 365 UV Led torches and check whether I can find anything which fluoresces white. Maybe I can get them to turn out the lights.

[colinbm]

I have made this an absolute UVIVF of this Alabaster egg.

Camera - normal Sigma fp.

Lens - Canon 40mm pancake filtered with Zeiss T* UV filter, blocking below 400nm.

Light - Alonefire H42UV filtered with 8mm ZWB1.

CWB - white PTFE / Teflon.

Back board - white PTFE / Teflon

 

To my eye this was a very faint orange. Perhaps the exposure could be reduced.

I have made no changes to the DNG RAW except to convert to .JPG in Sigma SPP & crop & save for the Web in IrfanView.

 

 

 

PS, there is a Stainless Steel hose clamp on the bottom right of the black plastic clamp.

[dabateman]

That image looks wild.

Why did you use the 8mm zwb1 on the flashlight?

That seems like a lot. But definitely wouldn't be any visible or IR leakage from the flashlight.

[Andrea B.]

That image indeed looks wild !!! I think we are all not-saying what it looks like.

 

Anyway.......nevermind......back to business.

 

The conclusion is that the alabaster does not fluoresce white? Bummer.

[Guest]

Off topic. Has anyone tried bleached coral. Seems pretty white to me under the torch. Calcium carbonate?

[colinbm]

Thanks Andrea & Dave

Andrea, now I can't un see it !

Dave, that is what I wanted the 8mm ZWB1 for & I am using it !

As the Irish say, to be sure, to be sure.