Author Topic: Size and color  (Read 2682 times)

Offline PeterXXL

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Size and color
« on: July 20, 2015, 02:48:28 PM »
Kephra: Ref. to what you wrote at http://www.cgcsforum.org/index.php?topic=1292.0

Is there any fix relationship between the wavelength of light an the size of nanoparticles?

I mean,  when we see the color yellow for colloidal silver it means that the light spectrum with as wavelength of ~380 to 450 reflects against the nanoparticles, which equals to color in the range violet to blue, and the absence of that light is perceived as yellow by our eyes. But what actually is the size of the nanoparticles then? I assume that it's between 10 and 30 nm then. But for colloidal gold our eyes perceive it as red, which correspond to the absence of wavelength about 485 - 600, equals to the absence of light blue to green. Doesn't that equal to a particle size that is much larger, like  50 - 100 nm?

« Last Edit: July 20, 2015, 03:11:30 PM by PeterXXL »

Offline kephra

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Re: Size and color
« Reply #1 on: July 20, 2015, 05:21:53 PM »
Kephra: Ref. to what you wrote at http://www.cgcsforum.org/index.php?topic=1292.0

Is there any fix relationship between the wavelength of light an the size of nanoparticles?

I mean,  when we see the color yellow for colloidal silver it means that the light spectrum with as wavelength of ~380 to 450 reflects against the nanoparticles, which equals to color in the range violet to blue, and the absence of that light is perceived as yellow by our eyes. But what actually is the size of the nanoparticles then? I assume that it's between 10 and 30 nm then. But for colloidal gold our eyes perceive it as red, which correspond to the absence of wavelength about 485 - 600, equals to the absence of light blue to green. Doesn't that equal to a particle size that is much larger, like  50 - 100 nm?
In that post I said that the size of the particle determines the color.
What the nanoparticle is made of also determines the color.  Thats why gold is red and silver is yellow for the same approximate particle size.
Nanoparticles absorb light of a specific wavelength stronger than other wavelengths which is why they might look one color when we view white light through them, but the complementary color when we reflect light off of them as happens with very turbid solutions.
There is the unknown and the unknowable.  It's a wise man who knows the difference.

jossie5461

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Re: Size and color
« Reply #2 on: September 04, 2015, 12:11:07 AM »
Hi,
I made the ionic silver solution and then added the reducing agent (light karo and distilled water, 4 drops) 1 pt. heated the glass jar (jar was on top of metal grate) on a electric stove on low/medium for about 45 min./1 hr.  Everything was sterile.  Problem is it didn't turn yellow only very slightly. After cooling I tested with a TSD and still get .19 ppm.  [size=78%]What does this mean, is it colloidal, or still ionic?[/size]
[/size]
[/size][size=78%]The above was the second batch I tried. The first batch was a 8oz. jar and added the reducing agent and microwaved for 1 minute. That didn't turn yellow either and is still reading .36 ppm.[/size]
[/size]
[/size][size=78%]I'm using a 12v battery pack that I have for emergenies.[/size]
[/size]
[/size][size=78%]Don't know if either one is good colloidal silver.  I am far from a scientist, please advise![/size]

Offline kephra

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Re: Size and color
« Reply #3 on: September 04, 2015, 12:23:08 AM »
What exactly did you do?  Did you use the correct amount of electrolyte?  What current did you use?  How long did you do the process?  Are you using a constant current generator?  Why are you using a TDS meter?
There is the unknown and the unknowable.  It's a wise man who knows the difference.

jossie5461

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Re: Size and color
« Reply #4 on: September 06, 2015, 08:17:56 PM »

Thanks for the fast response,I don't know how much electrolyte I used. (I used eye contact solution)  I didn't understand how you were measuring on the video. I'm not a chemist, I didn't think it had to be a exact measure. I don't know what kind of meter you are using either.  Yes I did buy a TDS, thats where my ppm's came from.  I used the Karo mix, 4 drops.  I don't have a furnace or what ever you used on the video to reduce the ionic silver.

I just tried to reduce it again today with a heavy fry pan(dry) and a empty tuna can with water, my ionic silver on top. Done on my electric stove(on medium) for two hrs. No color change. I bought a laser light cause I saw that on the web. It definietly shows there is silver in the water. My ppm's went up from 36ppm to 56ppm. Does that mean anything.

Offline kephra

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Re: Size and color
« Reply #5 on: September 06, 2015, 08:20:43 PM »
Before you do that, please read the first 4 numbered articles in the Articles section.  You are really far off track, and you are not doing yourself any favors by not reading the articles.  And I have no idea what video you are talking about.
There is the unknown and the unknowable.  It's a wise man who knows the difference.

jossie5461

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Re: Size and color
« Reply #6 on: September 06, 2015, 08:49:15 PM »
I found this forum from ZeroFossilFuel video 386, youtube. I guess I got the wrong place.
Thanks anyway,

av00va

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Re: Size and color
« Reply #7 on: November 01, 2015, 03:51:31 AM »
Sorry for posting a reply to an old topic. I feel it is relevant to the quality of my sample.

What yellow should I be shooting for? I am making collodial silver. When I make it, it seems to boil at a certain point. I keep it from boiling, but after about 15 minutes, it turns dark yellow. I am under the impression that the darker the color, the larger the particle. What particle size/color should I be looking for?

Offline cfnisbet

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Re: Size and color
« Reply #8 on: November 01, 2015, 09:10:05 AM »
Bright, light yellow. A little darker if you use cinnamon or gelatine as a capping agent.