How many different dyes exist and are they permanent?

How many different dyes colors exist? Can they be all bought at the merchants or are there any specials/rare that could be obtained differently?

And finally, which equipment categories can be colored? Is this color permanent or can I apply another dye if I am not happy of the result?

Solution 1:

There are 22 dyes, per: http://us.battle.net/d3/en/item/dye/

Dyes:

• Aquatic Dye: Light Blue
• Spring Dye: Light Green
• Tanner's Dye: Brown
• Winter Dye: Gray
• Autumn Dye: Orange
• Cardinal Dye: Dark Red
• Desert Dye: Light Brown
• Ranger's Dye: Yellow Green
• Royal Dye: Purple
• Elegant Dye: Fuchsia
• Lovely Dye: Pink
• Mariner's Dye: Blue
• Summer Dye: Yellow
• Abyssal Dye: Black
• Forester's Dye: Green
• Golden Dye: Gold Yellow/orange
• Infernal Dye: Red
• Purity Dye: White

Collector's Edition Dyes: (unlimited uses)

• Bottled Cloud: Beige
• Bottled Smoke: Dark Gray

Special dyes:

• Vanishing Dye: Makes invisible
• All-Soap's Miraculous Dye Remover: Returns to original color

Dyes are permanent in that they do not wear off, but you can re-dye armor.

Items/slots that can be dyed: (No legendary items can be dyed!)

• Helm
• Shoulders
• Chest armor
• Pants
• Gloves
• Boots

Solution 2:

Diablo 3 has shipped with 21 dyes, and 2 dyes exclusive to the collector's edition (Bottled Smoke and Bottled Cloud, listed as Beige and Pale on the above link). There is also 1 dye remover, that removes a previously dyed piece of equipment. All dyes can be dyed over each other without issue.

The collector's edition dyes are not consumed with use, but the regular dyes are.

Every visible piece of armor is dyeable, which means Shoulder, Chest, Pants, Boots, Hat, Gloves and Bracers (but not belts, amulets, rings, or weapons).