Hi Priscilla, I have been playing with Titanium and Niobium and can
easily get all the colors of the rainbow by this method:
1) I purchased the Anodizer from Reactive Metals.
It is sort of expensive and
I have found several articles on how to make one yourself, but I
opted to buy it.
2) Using the Anodizer, I hooked it up to a digital voltmeter so I
could tell exactly what the voltage it was putting out.
3) I took a strip of Titanium about 6 inches long, and hooked up one
lead (the negative lead I think) to the strip, and hooked up the
other lead to an alligator clip.
4) To the alligator clip, I hooked up a very small artists paint
brush, by connecting to the metal ferrule that holds the bristles.
5) I dipped the paint brush in my pickle jar to get a little acid on
it for conductivity, turned up the voltage to about 10 Volts, and
painted a stripe across the Titanium strip. If it didn't react, I
turned up the voltage a little more until I got the first indication
of oxidation, which was a faint yellow coloring. I used a black fine
magic marker to label this line with the voltage it took to get this
6) Then I raided the voltage by .5 volt, moved over about 5 mm and
painted another strip, which gave me a darker yellow. I marked this
line with its voltage.
7) By the time I got to the end of the strip, about 40 volts or so,
in half volt increments, I had gone from light yellow, thru pink and
purple , to dark blue, to a bright iridescent blue.
I did the same thing with a strip of Niobium.
Now, when I want a particular color, I look at my strip, crank up
the voltage to the color I want and paint away. You can paint any
color right next to each other, or raise a previous color to a
higher voltage and color.
If you go to far and want to backtrack, buff or sand off the
oxidation, and start over again.
Love and God Bless