Vial of Dye

Basics
A Vial of Dye (usually just called Dye for short) can be used to change the color of Items.

Dye comes in the following colors:

Usage
Most armor and weapons can be dyed. Dye is used by double-clicking on the Vial of Dye, then clicking on the item you wish to dye, if it is in the inventory, currently being worn, or in storage. This will bring up the Dye Preview panel. You may place up to 4 dyes into the preview panel. The panel will show the result of the dye(s) on the item.

Backpacks, belt pouches and bags can also be dyed. This does not affect the character's outward appearance. It only changes the bags' color in the inventory window. Bags become dyed immediately, without a preview window. As such, they cannot have mixtures applied to them.

It is advised that you use the dye preview panel to examine the results before applying the dye. The window shows exactly how your equipment will look after applying the dye. Dye is gone forever once used, and cannot be salvaged or removed. The only cure for a bad dye job is to dye it again.

Dye does not produce the exact same color on all equipment. Purple dye shows up purple on Mesmer armor, but a light lavender on Elementalist armor. Some items dye very differently from normal, such as the Chaos Axe and Necromancer Ascended Scar Pattern Armor. For example, using blue dye on a Chaos Axe will turn it red.

Silver will not make non-metallic equipment shine. For example, the Elementalist Elite Stormforged armor is dyed only in the cloth non-metallic parts. Dying the set silver will just make the cloth parts a light grey. The already shiny lightning is always white.

Some items, such as the Eternal Bow and the Necromancer Ascended Scar Pattern Armor, will accept dye but do not change noticably when dyed.

Some weapons and armor (such as Eternal Shields and Elementalist Headgear) cannot be dyed.

Hero Armor cannot be dyed.

Unique items cannot be dyed, with the exception of Straw Effigies

The starting color has no effect on the resulting color. There is no need to dye your equipment grey before dying it what you want.

Mixing Guild Wars Armor Colors
You can mix dye effects in the dye preview screen by simply dragging the dyes you wish to mix into the appropriate slots. Once you have the color you want click apply and the mix is applied directly to your armor. You no longer can mix dyes together to create a "Mixed Dye". Colors can be mixed only in the Dye Preview window, which then is only mixed when applied to the armor.

You can also use grey in dye mixes; in this case the remover acts as the base color of the item the dye is applied to. For example, if you mixed a grey dye and a green dye and applied it to a Necromancer armor (base color Red), the resulting color would look the same as if you had applied a red + green mix. Each class's armor has a base color, as follows: Warrior = Yellow, Monk = White, Ranger = Tan, Necromancer = Red, Elementalist = Purple, Mesmer = Green, Assassin = Blue, Ritualist = Orange, Dervish = Brown (Update as of 4/14/07)- "Newly crafted armor now starts out gray. If you dye it to another color and then later want to restore it to its original appearance, just dye it gray. Vendors now sell gray dye instead of dye remover."

You can also see All dye combinations. (some combinations may be inaccurate)

Some general tips for mixing dyes:
 * Mixing Silver with another color produces a dull metallic version of that color. More specifically, adding silver dye in a mix increases contrast and decreases saturation.
 * Yellow + Blue usually makes a dirty yellow, although on some metallic armors it comes out as light blue.
 * Orange + Green generally makes a light brown color on cloth armor, or a rusty brown on metallic armor.
 * Red + Green makes a nice orangish bronze on some armors, and a dark brown on others.
 * Yellow + Purple makes a brown color, slightly lighter than the official brown dye you can choose for your armor when you make a new character. This combination very closely resembles the official brown dye on cloth-based armors, such as Assassin, Ranger, and Monk. It also makes a nearly official red dye color on metallic armors. On Elementalist armor, yellow and purple make a dark purple instead of the light lavender of purple alone.
 * Red + Blue makes lighter purple than the standard purple dye.
 * Red + Yellow makes an orange, but it is more red than standard orange dye.
 * Red + White will generally give you a pinkish color
 * Silver + Red can sometimes generate a crimson color
 * Red + Brown gives an almost blood-red color
 * For a perfect blood red on most armor, use Black + Black + Red + Orange.
 * It is said that mixing purple and green dyes will come out black on most Necromancer scars, sometimes even white, like the sunspear scar. On most armors it will come out black-brownish.

Dye Notes

 * Before the October 25, 2006 update, Merchants sold Dye Remover instead of Gray Dye.
 * Dye behaves differently depending on the type of armor it is applied to. For some, applying black dye will turn the armor into a dark purplish color. Others may result in more of a dark gray. Before accepting to dye your armor, you may want to consider trying combinations inside of the preview window, to get a more desirable look for your character.
 * Dye is a somewhat valuable commodity, and as such is sometimes a target for farming. It is commonly believed that dye drops more frequently in Pre-Searing. For more information on farming dye in pre-Searing, read the Green Hills County dye farming guide or Bandit Raid Dye Farming (Pre Searing). Also, in Wizards Folly (Pre-Searing), the Hulking Stone Elementals and Stone Elementals drop quite a few vials of Dyes as well.
 * Black dye or White dye are very rare drops. These have the obvious effects of increasing the market value of their specific vials of dye. New players are often unaware of this fact and occasionally fall prey to scammers (see dye scams for details).
 * Silver dye has the same drop rate as all other dyes except for black or white. However, its market price is generally higher than other non-high-end dyes because it is more sought after. Recently the prices for silver dye have dropped substantially due to the inclusion of gray dye.
 * Since the release of Nightfall, when you put a dye on your armor, a Dye Preview panel will open that allows you to see what your dye will look like on that armor, along with other items such as weapons, shields, bags, or even the end result of dye mixes.
 * If you are wielding a 2 handed weapon (bow, scythe, daggers, hammer, staff) and try to dye a one handed item (wand, sword, axe, shield, offhand) the said item will not appear, as when wielding a 2-handed weapon anything wielded by the other hand is omitted.
 * The same colored dyes can not be mixed together alone. For example, you cannot mix only two silver dyes; you must have a separate color to go with the dyes, such as yellow or red.
 * Dying your armor or weapons is completely optional and will provide no bonus whatsoever.
 * Green/Unique Weapons cannot be dyed (with the exception of Straw Effigies)