There is an color changing ink on new american banknote , this is an ink which contains collodial gold or silver. There is an extensive list of patents at google patents and uspto.gov.
Particles goes to 100 to 1 nanometer diameter or so , they tend to change their colors with receiving photon, wait, resonate and release an new color. This new color is different than what we see than bigger particles .
Gold tend to go in fuschia color and can be manipulated to wide range of colors including deep reds to purples and green.
Silver goes to yellow and orange colors,green , blue..
Platin goes to brown when it is in nanoparticle state.
Turkovich method is the best to manufacture them. But it needs several heating and cooling steps plus rules while adding new chemicals to solution plus stirring rules.
I will find the recipe of these today. You can google collodial gold silver ink and recieve many patents.
Last edited by Mustafa Umut Sarac; 11-09-2012 at 10:13 PM. Click to view previous post history.