To change the color of leather, it's best to dye it so that the color permeates the leather and doesn't sit on top. But you can't use just any dye; you need a special leather dye to ensure a deep, rich and lasting color. Before you can stain or dye leather, identify the type of leather you have, as bonded leather, for example, doesn't take a dye well. Aniline leather takes dye the best.
The Leather Type
The four basic types of leather finishes include aniline, semi-aniline, pigmented and suede or nubuck, in full-grain, top-grain, genuine or bonded leathers. It helps to know the type of leather and its finish before you begin the cleaning, preparation and dyeing process. Look at the furniture or item's tag for identification. Full and top-grain leathers are quality leathers that take dye well once you prepare them for the colorant. Genuine leather, which represents what's left of the hide after the top is removed for higher grades, accepts dye easily, as opposed to bonded leather, which is scrap leather ground up and mixed with glue with a surface that replicates the look of leather.
Move the leather couch or other piece to be dyed to an area with adequate ventilation where you can work on it easily, such as a garage, workshop or spare room. Cover the floor with a dropcloth to protect it from spills. Wipe down the leather with a lint-free cloth dipped in warm water to remove stuck-on debris or dirt. Clean it thoroughly, but don't overwet the leather. If you have a leather cleaning -- not conditioning -- product, you can use that to remove the grime. For items that have a protective topcoat, such as semi-aniline or pigmented leather, apply a leather deglazer to remove this finish, even on all of the cushions' sides. Let it dry.
Apply the Dye
Working in small sections, first spritz the area you plan to dye with a spray bottle filled with distilled water. The area requires a bit of moisture to help spread the dye. Add the well-mixed dye to a soft sponge or lint-free cloth and apply it, working it into the selected area. Repeat these steps across the entire couch and individual cushions, if removable, until you have a single coat of dye or stain covering the leather. Allow it to dry at least two hours or longer, until it is dry to the touch, before applying a second coat. The leather may need a second or third coat to deepen the color, especially if you apply a lighter color over a darker one. Remove excess dye as you work, using a clean cloth.
After the leather has been stained or dyed and is completely dry to the touch, add an acrylic leather sealant to protect the leather and its new color. Some sealants may have a colored tint that dries clear. Apply the leather sealant with a clean and soft damp sponge or lint-free cloth to avoid fine cloth hairs from becoming attached to the sealant coat. An acrylic leather sealant provides a water-resistant surface that protects the leather from spills.