Before experimenting on your home bathtub and wall tiles, it is better if you call professional refinisher that can help evaluate whether your home tile can be transformed or just need a replacement. If the tiles are in good condition, you can paint them and restore the new look at minimum cost.
Painting wall tiles is the most convenient project that you can tackle in a weekend and renovate your bathroom instantly. However, you must know that painting wall tiles is just a temporary solution and you can depend on it for few years until you get a budget to retile your bathroom space.Things needed for the project-
It is crucial to clean the tiles well and make them dirt or grime free, as this will affect the bonding between paint, primer, and tile surface. Other tip is to fix every crack in grouting prior painting. You can mix a grout batch to fix the cracks and let them dry. Once these are dried, clean the excess. Do check that all windows and doors are open for proper ventilation.
In case you are using tile primer with oil based enamel paint, you must apply the primer before paint. You can use a foam roller to distribute primer evenly on the tiles surface. This will take whole night to get dry. However, if your bathroom is not humid or moist, you can start painting as soon as primer gets dry completely.
Paint your wall tiles and apply double coats for better result. Apply the second layer once the first layer of paint dries. Make sure your bathroom is not humid because it can affect the paint and result in peeling paint in a few months.