How can absinthe be colored into a different colour other than green? Some days ago I was walking on the street and passed by a beverage store where I saw some bottles of absinthe.

There were green, red and blue versions, and I thought how could absinthe, a classically green colored beverage, be transformed into a totally different color; and what's more, a primary color which is supposed to be impossible to create by mixing other colors.

I have two theories: 


Absinthe is always green due to the presence of Artemisia absinthium's chlorophyll. The beverage is based in and some kind of product is added in order to create a reaction to make it turn to X color. 
Absinthe is transparent until you add the Artemisia absinthium's chlorophyll. Somehow, you can add colorant to the transparent beverage and eliminate the chlorophyll.


I'm attaching an image for you to know what I'm talking about:

These are the ones I saw
Clear Absinthe

Absinthe is made much in the same way that many gins are.  You take neutral spirits, add botanicals (wormwood and anise), and re-distill.  Anything that comes out of the still will be clear.  Some absinthes at this point are finished, these will be called blanche (white) or sometime la bleue.  The first absinthe available in Val-de-Travers (the birthplace of absinthe) after the ban in Switzerland was lifted was a blanche.  That same bottling was the driving force behind making it legal in the United States (interview of lawyer who fought the ban).  It can be really good stuff.  Any of these can be really easily colored.

Green Absinthe

Usually absinthe gets a second chance to mingle (macerate) with some herbs after it's sprung from the still, this style is known at verte.  This is when it gets it's color, as well as some extra flavor and aroma. It's a more complex flavor.  The color that the chlorophyll imparts is dull.  If it's neon green there was food coloring added and some of these "greener" varieties are actually blanche at heart.  Also of note is that sometimes these food colored types add sugar, to make it friendlier to less experienced drinkers (or to hide poor distillation technique as happens with vodka).  There is at least one non-green bottling that I know of that is still macerated post distillation, but uses hibiscus which turns it red.  These methods of coloration don't make them any less of a true absinthe, they do use wormwood (and equally important, anise).

Czech Absinth (without the e)

The most common non-green "absinthe" is so called Czech-style, also known as Bohemian style.  These are not rightly called absinthe and are historically known for very low quality.  Instead of distilling the botanicals in the alcohol, they are cold compounded.  It's made either by mixing spirits, flavoring oils, and food coloring or by macerating the botanicals without distillation.  Be wary of absinthes much over 140 proof, as they are frequently Czech-style.  Do be aware that they're called Czech-style because that's where the style originated and where most of this variety still comes from, however the Czech Republic does have good examples of absinthe.