I just did a lot of google searching for "teal anodize" and "turquoise anodize" and "teal aluminum" and the like for photographs. Then any forum post results that came up. There are a few brands of dyes you can get. One guy sells USSpecialty dyes on eBay here:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=251188199995&ssPageName=ADME:X:RTQ:US:1123I've chatted with him too. I got my dye from Caswell Plating, as I stumbled upon posts there, and they sell "teal" and "turquoise" shades ($15 for small bottles, ~$3 delivery)
http://www.caswellplating.com/electroplating-anodizing/anodizing-products/anodizing-dyes.htmlI was torn between teal and turquoise, but ended up going with turquoise, as it was also what MistakeMistake had used and verified to have a fair amount of green in it. I was afraid that teal would turn out too green in indoor lighting. There are other brands to consider as well, but these two are easily available in small quantities.
So the bottles say they are for 2 gallons of solution. However, you can dilute them in a much greater volume of distilled water--we did something like 8 gallons. As long as pH is correct, lower concentration of dye just means you will be dipping your part for a longer period of time to get the intensity you want. My cover was dipped for around 10 minutes (I dipped it myself). It's important to either have some artificial water agitation with some pump/bubbles or hold your part on a rack and slosh it around under water gently, for more even coverage.
Some dyes can be very "moody"--I'd research them individually. They can be picky about pH level or not very picky. Some dyes do better in heated water, and some are okay at room temperature. One important lesson I've learned is that it's important to take out your part periodically and inspect for color intensity, as it's easy to go too dark. When your part is in the solution, it's all slick with water, and the color looks a lot more vibrant and lighter. When it's sealed and dried, it will be matte, and the way it will reflect light will change how the color appears. It's best to go lighter than too dark, unless dark is what you're looking for.
NEVER touch anything anodized before dying--it WILL leave uneven splotches on the finish where the dye won't penetrate well. Even if you wear gloves. We did that accidentally during initial anodizing tests, and you could see exactly where the cover was barely touched--in rubber gloves. Also if you give your cover to an anodizing shop, make sure they have a proper rack to put it on for the anodizing and dying process, because where the rack touches the cover, there will be some small silver marks. If you use a proper rack and place it strategically underneath the cover, the end result will be tiny barely visible pin-like silver dots in a few spots where you won't ever see them. But initially my shop wanted to use a thick wire through the USB port hole, which I said would definitely be less than ideal. They switched to more common anodizing racks after that, gripping the part underneath at tension, so there are only a few of those tiny silver dots remaining.
And finally about color accuracy again: it's true what people say about anodizing dyes: it's difficult to get the exact color you want and then repeat it. It's a bit of a creative process to anodize evenly and to the shade you want, especially if you dip into different colors to blend some shade. Furthermore, the thickness of the anodizing coat and material itself can have an effect on how the dye will manifest. The same turquoise dye could have been more blue and darker than how my cover came out. Finish is also a major factor: whether it's smooth, sand-blasted, or bead-blasted. Also, when removing anodizing by chemically stripping the existing finish, you're going to smooth out the original finish a bit each time and result in an increasingly smoother finish. It's not a good idea to reanodize many times without refinishing too. In my case we were fine, and the finish still looks great.