Dark Water 1000nm with converted Sigma fp.

Started 3 months ago | Discussions thread
xpatUSA
xpatUSA Forum Pro • Posts: 19,562
Re: Dark Water 1000nm with converted Sigma fp.

Scottelly wrote:

xpatUSA wrote:

Scottelly wrote:

xpatUSA wrote:

SigmaTog wrote:

Dark Water 1000nm with converted Sigma fp.

Interesting, Colin.

At 1000nm, water absorbs energy about 1000 times more than visible light:

http://hyperphysics.phy-astr.gsu.edu/hbase/Chemical/watabs.html

Wouldn't it depend on the ppm concentration Ted?

I'm sure it would Scott.

Er, ppm of what ... ?

Whatever is making it dark Ted. I'm assuming the photo was shot using some black food coloring in water, but it could be laser printer toner, which is generally finely ground carbon powder, which coats tiny polymer pellets (plastic beeds), if I'm not mistaken. When the powder is pressed against the paper by a hot roller, the pellets melt, adhering the black carbon powder (probably just left over coal ash, which is ground into an almost nano-particle sized fine grain) to the paper.

Colin used clean water, Scott.

What he is demonstrating is the absorption of light at a wavelength of ~1000nm.

At that wavelength, liquid water absorbs 100 times more light than visible red, 1,000 times more than visible green and 10,000 times more than visible blue. Therefore it looks dark compared to the Pyrex glass.

http://www.idc-online.com/technical_references/pdfs/chemical_engineering/Water_absorption_spectrum.pdf

See web page 7.

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