... I take the chance to mention here that I have 
just uploaded an image to my web site that shows an
example of how a normal BIC ball-point pen looks 
when illuminated with polarized light and then 
photographed through a macro lens with an attached 
polarization filter.

To view it, click on the 3rd hyperlink on this page:

http://www.crosswinds.net/~tok/MacroImage.html


I find these optical properties very fascinating.


Tor Olav
-- 
mailto:tor### [at] hotmailcom
http://www.crosswinds.net/~tok/tokrays.html

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Tor Olav Kristensen wrote:

> ... I take the chance to mention here that I have
> just uploaded an image to my web site that shows an
> example of how a normal BIC ball-point pen looks
> when illuminated with polarized light and then
> photographed through a macro lens with an attached
> polarization filter.

Cool, iridescent! (er, photoelastic!)

--
David Fontaine  <dav### [at] faricynet>  ICQ 55354965
My raytracing gallery:  http://davidf.faricy.net/

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in <3A4EA1E7.EA26A5C0@online.no> Tor Olav Kristensen wrote:

>I find these optical properties very fascinating.
>

Nice stuff to play with.
Here's a realy old one I dug up.
<http://members.home.nl/seedseven/stress_test.jpg>
Top is between crossed pola's.
Bottom, a 1/4 lamba plate is added (I think).

With a polarisation microscope I made hundreds of pictures of
minerals and "schliffs" from bore hole samples while I worked
for an oil company.


Ingo

-- 
Photography: http://members.home.nl/ingoogni/
Pov-Ray    : http://members.home.nl/seed7/

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I remember using polarised images of crystals when we did "light shows" in
the seventies. They have always fascinated me.

Mick

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Tor Olav Kristensen wrote:
> 
> ... I take the chance to mention here...

There is nothing wrong with your action...

> I find these optical properties very fascinating.

As do I. Well done !

-- 
Ken Tyler - 1400+ POV-Ray, Graphics, 3D Rendering, and Raytracing Links:
http://home.pacbell.net/tylereng/index.html http://www.povray.org/links/

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The inside of paprika?  Dear man, but my god!  The codliver oil I can
undestand, however Paprika is taking it just too far!

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David Fontaine wrote:
> 
> ...
> Cool, iridescent! (er, photoelastic!)

Thanks !


Regards from Tor Olav
(who's running to his encyclopaedia to look up "iridescent")
-- 
mailto:tor### [at] hotmailcom
http://www.crosswinds.net/~tok/tokrays.html

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ingo wrote:
> 
> in <3A4EA1E7.EA26A5C0@online.no> Tor Olav Kristensen wrote:
> 
> >I find these optical properties very fascinating.
> >
> 
> Nice stuff to play with.
> Here's a realy old one I dug up.
> <http://members.home.nl/seedseven/stress_test.jpg>
> Top is between crossed pola's.
> Bottom, a 1/4 lamba plate is added (I think).

Very clear illustrations of the phenomena,
but what is a 1/4 lambda plate ?


> With a polarisation microscope I made hundreds of pictures of
> minerals and "schliffs" from bore hole samples while I worked
> for an oil company.

I didn't know that minerals had these properties as well.

Did you use some kind of (semi-)transparent minerals ?

Do you know of any "everyday" mineral materials that I 
could use for experimenting ?

And what are "schliffs" ?


Regards,

Tor Olav
-- 
mailto:tor### [at] hotmailcom
http://www.crosswinds.net/~tok/tokrays.html

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Mick Hazelgrove wrote:
> 
> I remember using polarised images of crystals when we did "light shows" in
> the seventies. They have always fascinated me.

In discotheques ?

You say that you used images of crystals,
but wouldn't it be possible to use the crystals themselves ?

Its a pity that I don't have any crystals at hand to play with.


Tor Olav
-- 
mailto:tor### [at] hotmailcom
http://www.crosswinds.net/~tok/tokrays.html

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Ken wrote:
> 
> Tor Olav Kristensen wrote:
> >
> > ... I take the chance to mention here...
> 
> There is nothing wrong with your action...

OK.


> > I find these optical properties very fascinating.
> 
> As do I. Well done !

Thank you.


Tor Olav
-- 
mailto:tor### [at] hotmailcom
http://www.crosswinds.net/~tok/tokrays.html

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Dearmad wrote:
> 
> The inside of paprika?  Dear man, but my god!  The codliver oil I can
> undestand, however Paprika is taking it just too far!

Sorry. It was a just "a momentary lapse of reason".


Regards from Tor Olav
(who still think it would be nice to be inside 
a red paprika with strong light outside. =)
-- 
mailto:tor### [at] hotmailcom
http://www.crosswinds.net/~tok/tokrays.html

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In article <3A5284EA.17FA70A7@online.no>, Tor Olav Kristensen 
<tor### [at] onlineno> wrote:

> (who's running to his encyclopaedia to look up "iridescent")

finish {
    irid {AMOUNT
        thickness FLOAT
        turbulence TURBULENCE
    }
}

:-)

-- 
Christopher James Huff
Personal: chr### [at] maccom, http://homepage.mac.com/chrishuff/
TAG: chr### [at] tagpovrayorg, http://tag.povray.org/

<><

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in <3A528654.CD0AB098@online.no> Tor Olav Kristensen wrote:
>
>Very clear illustrations of the phenomena,
>but what is a 1/4 lambda plate ?
>

A quarter wave plate is made out of a birefringed material (thin plates of 
mica). A birefringed material makes light of orthogonal polarizations 
traverse the material at different velocities. One wavefront will be ahead 
of the other by a distance that depends on the thicknes of the material. 
If one component is 90° ahead it is a quarter-wave plate. 180° is a halve-
wave plate.
It is for example used to determine wether you have circular polarized 
light or a combination of linear- and  non-polarized light.


>I didn't know that minerals had these properties as well.
>Did you use some kind of (semi-)transparent minerals ?
>Do you know of any "everyday" mineral materials that I 
>could use for experimenting ?
>And what are "schliffs" ?

To start with the latter, "schliffs" are higly polished and very thin 
slices of stone/mineral. If you make them thin enough you can look throug 
every stone. In for example a granite there are several minerals, each 
with its own optical properties. In polarized light each will show in a 
different colour and density.

Attatched a micrograph of Asperine in polarized light. Cant find the 
colour print :(

Ingo

-- 
Photography: http://members.home.nl/ingoogni/
Pov-Ray    : http://members.home.nl/seed7/

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Attachments:
Download 'asperine.jpg' (7 KB)

Preview of image 'asperine.jpg'

ingo wrote:
> 
> in <3A528654.CD0AB098@online.no> Tor Olav Kristensen wrote:
> >
> >Very clear illustrations of the phenomena,
> >but what is a 1/4 lambda plate ?
> >
> 
> A quarter wave plate is made out of a birefringed material (thin plates of
> mica). A birefringed material makes light of orthogonal polarizations
> traverse the material at different velocities. One wavefront will be ahead
> of the other by a distance that depends on the thicknes of the material.
> If one component is 90° ahead it is a quarter-wave plate. 180° is a halve-
> wave plate.
> It is for example used to determine wether you have circular polarized
> light or a combination of linear- and  non-polarized light.
> 
> >I didn't know that minerals had these properties as well.
> >Did you use some kind of (semi-)transparent minerals ?
> >Do you know of any "everyday" mineral materials that I
> >could use for experimenting ?
> >And what are "schliffs" ?
> 
> To start with the latter, "schliffs" are higly polished and very thin
> slices of stone/mineral. If you make them thin enough you can look throug
> every stone. In for example a granite there are several minerals, each
> with its own optical properties. In polarized light each will show in a
> different colour and density.

Thank you very much for explaining Ingo.

I wish I had such "stuff" to play with.


> Attatched a micrograph of Asperine in polarized light. Cant find the
> colour print :(

Nice - I would love to see such images in colours !


Tor Olav
-- 
mailto:tor### [at] hotmailcom
http://www.crosswinds.net/~tok/tokrays.html

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Chris Huff wrote:
> 
> In article <3A5284EA.17FA70A7@online.no>, Tor Olav Kristensen
> <tor### [at] onlineno> wrote:
> 
> > (who's running to his encyclopaedia to look up "iridescent")
> 
> finish {
>     irid {AMOUNT
>         thickness FLOAT
>         turbulence TURBULENCE
>     }
> }
> 
> :-)

Ahh .... I'll try out this.

Thanks.


Tor Olav
--
mailto:tor### [at] hotmailcom
http://www.crosswinds.net/~tok/tokrays.html

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