To tie dye, you first soak the shirt or article of clothing in soda ash for a few minutes. This raises the pH level of the fabric so the dyes can better interact with it. You then wring excess moisture out of the shirt and tie the piece of clothing with rubber bands into sections and begin to apply the dye. The difference between wet and dry tie dyeing is the amount of moisture in the piece of clothing as you begin to apply the dye. For example, if you are wet tie dyeing, the article of clothing will be wet. But if you are dry tie dyeing, the article of clothing will be completely dry.
The big difference between the two tie dyeing techniques is how the dyes react with the fabric. For example, in wet tie dyeing, the dyes will tend to run more and blend in with the other colors. This occurs mainly in "transition areas," which are places where one color ends and another one begins. In these areas, typically the two colors will blend together to create a third color. Dry tie dyeing produces more crisp color definition because the dyes don't run.
In terms of ease, tie dyeing a wet article of clothing takes the cake. This is because the damp article of clothing allows the dyes to soak into the fabric better and produce the colors and patterns quicker. Dry tie dyeing, on the other hand, generally takes more time to complete and more dye to do so, as the dried fabric needs to absorb more of the dyes compared to wet fabrics. Dry tie dyeing also doesn't tend to spread the coloring out at the same rate as wet tie dyeing.
One of the lone drawbacks to wet tie dyeing is that it's a bit messier than dry tie dyeing. That's because in addition to working with the dyes, you're also working with an article of clothing that is damp. Furthermore, you must let your tie-dyed article dry after you're done dyeing it. In wet tie dyeing, these times generally take longer than dry tie dyeing. Dharma Trading Co. recommends letting the wet article dry four at least four hours, but as much as 24 hours to get brighter colors.