If you look on the back of a can of latex paint you'll notice the manufacturer has printed a list of drying times. They will tell you to wait a certain time before touching and a certain time before you can apply another coat. It can be confusing until you understand how latex paint dries. Paint isn't like hair; just because it feels dry doesn't mean it really is. It must go through a lengthy process of curing that enables it to create a firm bond with the surface it is on.
As latex paint dries, the solvent and water within it evaporates. The more solvent that evaporates from the paint, the more durable the paint becomes. "Dry to the touch" is the shortest drying time listed on most paint cans. It means you can put your hand on a freshly painted surface without getting paint on your hand. It does not mean that the paint is okay to walk on or that you can add a second coat of paint to your freshly painted surface. The solvent has evaporated only from the surface of the paint, not underneath. Until all the solvent has evaporated, the paint is still easily damaged and needs to be handled with care.
Other Drying Times
Even though the paint is dry to the touch, it does not mean it has created a strong enough bond to withstand other uses. That's why paint cans also list a "recoat time" and a "use time." The "recoat time" is the amount of time that paint must dry before you can apply a second coat over the first. This time is usually one to two hours. The "use time" is the amount of time that paint must be allowed to dry before you can use it or place objects on it. This time will around 24 to 48 hours. But even 48 hours is not enough time to cure latex paint.
Curing is the time it takes for latex to become durable and harden. When all the water and solvent have evaporated, the paint has cured; it has created a firm bond with the surface. This is often listed on the paint can as the time you must wait before scrubbing or washing the paint. It usually takes two to four weeks for latex paint to cure. Curing time can vary depending on the paint. For example, low-gloss latex paint cures faster than high-gloss paint.
Drying and curing times given on paint cans are for optimal conditions. This means when the ambient temperature is between 65 to 85 degrees Fahrenheit and the humidity is below 50 percent. Painting under other conditions can speed up or slow down the drying and curing times. You don't want to do either, even if you're in a hurry. Changing the drying time either way can weaken the bond between the paint and the surface causing it to blister, crack and peel.