I became a member only to answer this post. I'm a professional fine artist specializing in inks and paints. Forget everything you just read above this post. It's 100% inaccurate. What you are looking for is optically-variant ink. It IS expensive, but you can buy it. There are no regulations preventing you from purchasing it. This type of ink is usually sold in 1kg containers, as most of the labs are outside the US- hence the metric system. Typically, this type of ink is purchased by large manufacturers, so that is why the large minimal purchase. Also, expect to pay around $300 for the ink. This is sort-of a trade secret of artists here, so take it for what its worth... but if you don't really need that much ink, you can call up a company and ask if you can have a sample of inks- something like half an ounce of each color they have currently available. You want to speak with the secretaries, not a salesman. They will often do it for around $20-$50 dollars, just be courteous and ingratiating. There are many companies that carry this type of ink. Just look them up online and start calling them. Shouldn't take you too long to get what you need. Hope this helps.