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Melanin clusters in UV


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#1 Reed F. Curry

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Posted 18 October 2014 - 16:39

The two photos that follow illustrate the detail UV can capture of melanin clusters below the skin surface.
First, the freshly-washed hand in visible light:
Posted Image


Now the same hand in UV (Nikon D40, Ludwig Meritar 50/2.9, Andrea U, UVP Blak-Ray B-100 lamp with Well's filter)

Posted Image


It is this ability of UV to reveal hidden skin properties that, I hope, dermatologists will learn to use more often. Forensic dentistry already uses reflective UV on skin for evidence of bite marks. Even bites that didn't break the skin have left perfect dentition marks as melanin clusters five months later.

Edited by Reed F. Curry, 18 October 2014 - 16:40.

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Reed
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#2 colinbm

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Posted 18 October 2014 - 22:46

That look good Reed
That lamp looks useful.
The Melanin Clusters shown here, is this good / bad for the person's health ?
I am not familiar with the Well's Filter ?
Col

#3 Reed F. Curry

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Posted 18 October 2014 - 23:20

Col,

Sorry, I mis-remembered the scientist's name. It is Wood's glass that is used on the B-100 lamp. See http://en.wikipedia.org/wiki/Wood's_glass

The B-100 is a rugged, commercial lamp used for inspecting large milk-transport and storage vats for any vestiges of life forms. They can be purchased relatively cheaply on ebay, second-hand (see http://www.ebay.com/...=item3f3e0cc56a ). I use it without the Wood's glass now. The Wood's glass is almost 12mm thick in the center.

The 150w Mercury HID lamp is quite intense, use glasses.

Edited by Reed F. Curry, 18 October 2014 - 23:23.

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Reed
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#4 colinbm

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Posted 18 October 2014 - 23:50

Thanks Reed
OK I am familiar with Wood's Glass :D
I have a 400watt HID UV lamp, that is made with Wood's Glass on the outer globe.
Actually I am looking for a piece of Corning 9780 or 9788 filter, about 6" or 150mm, round or square, either as cast or polished, to place in front of my lamp to rid it of the IR leak. This is not available to me in Australia.
Col

#5 Reed F. Curry

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Posted 19 October 2014 - 02:32

The Corning 9780 would take care of the IR leak, but a piece that size would be pricey in the Antipodes. Why not use a 10% CuSO4 solution between two glass plates? The 9780 doesn't pass nearly as much UV as the copper sulphate.

Posted Image

Above is the Corning 9780

as compared to the copper sulphate below:

Posted Image

I understand that the copper sulphate would heat up from the lamp. It should be workable, though, if you allow for expansion. Copper sulphate in a 10-13% solution between plates is used by many scientists as a lamp filter to eliminate NIR. (I have pounds of copper sulphate from my attempts at the optimum UV-bandpass camera filter :D
Best regards,
Reed
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#6 colinbm

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Posted 19 October 2014 - 03:35

Thanks very much Reed
That is very do-able, I even have some :D
I am imagining that you are talking about a 10% solution of copper-sulphate with water, Y / N ?
The question remains as to the thickness of the solution between the glass please ?
I do known that water is a good attenuator of IR, but my estimates had guessed at fish tank sizes, in front of the lamp :D
Cheers
Col

PS, If I use Perspex for the tank walls, it will pass the UV a little better ?
Col

Edited by colinbm, 19 October 2014 - 03:48.


#7 Reed F. Curry

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Posted 19 October 2014 - 20:18

Yes, copper sulphate and water. When I said a 10% solution, I mean create a saturated solution and then dilute any portion thereof with water by volume at a ratio of 9 parts water to 1 part copper sulphate saturated solution. In a previous career, I used to make saturated solutions of chemicals for staining wood. From the saturated solution I then take half and add an equal amount of water, that gave me 50%; take half of that, etc. down to 12.5%.

I think using Beer-Lambert you can get the proper thickness. Of course, enough Aussie beer would give a different thickness. :D
Best regards,
Reed
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#8 Reed F. Curry

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Posted 19 October 2014 - 20:26

Col,

Re your PS. If you can get Topas in sheet form, it will pass more UV than anything but Quartz.

P.S. -
Posted Image

Edited by Reed F. Curry, 19 October 2014 - 20:38.

Best regards,
Reed
http://www.uvroptics.com

#9 JCDowdy

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Posted 19 October 2014 - 20:41

View PostReed F. Curry, on 18 October 2014 - 23:20, said:

I use it without the Wood's glass now. The Wood's glass is almost 12mm thick in the center.
The 150w Mercury HID lamp is quite intense, use glasses.

I must advise you not to do that, the unfiltered HID UV lamp emits significantly hazardous UV.

#10 Reed F. Curry

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Posted 19 October 2014 - 23:33

John,

I understand that and do protect myself, both from direct and reflected UV. When using the lamp for curing optical cement, I leave the room while the light is doing its few minutes of work. When I use the lamp for photos of trout flies, I cover the lamp until ready for the shot, and use my remote shutter release.

However, it was intemperate of me to suggest that another person should work exposed to so much UV <320nm. My apologies.
Best regards,
Reed
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#11 colinbm

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Posted 20 October 2014 - 01:47

Thanks Reed
If I was to use Topas sheet for the tank, I might as well use a sheet of S8612 @ $500 or Corning 9780 @ $???.........
The lamps opening is 300mm x 300mm.
I'll try a 1" or 25mm thick tank of copper sulfate solution & see how that works.
This tank will weigh about 2.5kgs, so with the lamp at about 7kgs, that is OK. If I need to go to 100mm thick of solution, things will start to be too heavy.

Cheers
Col

#12 Reed F. Curry

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Posted 20 October 2014 - 21:46

Col,

I had a diagram for a commercial UV bandpass filter using CuSO4, I will look for it. There is also this type of water filter - http://www.lot-oriel..._sources_eu.pdf (scroll down to page 3). Of course, using copper sulphate, you could reduce the length of the filter to 20mm, as you say, depending on the concentration.
Best regards,
Reed
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#13 Reed F. Curry

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Posted 20 October 2014 - 22:09

Col,

Dr. Lasker, below, uses only a 5mm CuSO4 pathway to eliminate the IR leak of a UG11. He accomplishes that by using a 50% solution. That seems quite workable.
Posted Image
Posted Image
Posted Image

Posted Image

Edited by Reed F. Curry, 20 October 2014 - 23:30.

Best regards,
Reed
http://www.uvroptics.com

#14 JCDowdy

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Posted 20 October 2014 - 22:35

Reed,
Glad to hear you are practicing exposure precautions with that source. For me it is a familiar occupational hazard. I can tell you from personal experience, there are two kinds of people who work with powerful shortwave UV, those who have been burned and those who will be. The best place to be when such mean spectra are being scattered about is in the next room with the door closed!

#15 colinbm

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Posted 20 October 2014 - 23:26

Thanks very much Reed
This is great to see how the academics handle the problem.
I'll even make one of these cells for the 24watt Mercury HID Lamp, which will be on a similar scale to these.
Cheers
Col

#16 colinbm

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Posted 21 October 2014 - 13:29

Thanks again Reed
I have made a small tank / cell that is 40mm thick. I have mixed a batch of 13% copper sulfate. Its colour looks just like a BG36 BG39 filter :D
I have tentatively placed it in front of the 24watt Mercury HID lamp & looked at it through an Amici Prism Spectroscope & to my eye seems to attenuate the IR.
It is late at night here 'down-under' so I will get some sleep now. Later (tomorrow) I will photograph through the Amici Prism Spectroscope & post the comparison results here.
Cheers
Col

PS, I made a typo, the colour of the mixed batch of 13% copper sulfate looks just like a BG36 BG39 filter.
Col

Edited by colinbm, 21 October 2014 - 19:46.


#17 Reed F. Curry

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Posted 22 October 2014 - 00:33

Col,

As a fallback measure, or for a lighter weight, you might consider - http://www.ebay.com/...K%3AMEBIDX%3AIT . At 51 x 61 cm or 20 x 24" and 2 mm thick, it should do nicely. Marked down from $399.00 to $6.95.
Best regards,
Reed
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#18 colinbm

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Posted 22 October 2014 - 00:50

Thanks Reed
This is polyester film (mylar) 2mil, 2 thousandth of an inch, 0.05mm.
I am not sure how it will handle the heat ?
Col