The world looks like a completely different place under the ocean. Everything looks like it's floating in suspended motion and the water makes the rays of sunshine bend in a way you never see above water. The underwater world is difficult to capture if you only have experience painting above-water landscapes, but a little patience and the right tools can help you paint an underwater image. Start out slow and evolve your skills until your underwater paintings turn into something you are proud to call your own.
Sketch the landscape on your work surface (a wall, canvas or piece of paper all work well). Your image can include anything from a vast coral reef to a lonely scuba diver, so use any sketch you feel confident you can paint. Remember, the gravity is not as strong underwater, so allow the shapes in your sketch to stretch and twist in ways they wouldn’t above water.
Mix different shades of blue to create the proper background shades for the image. Use three different shades of blue ranging from light to dark. The lightest color will go near the top of the painting to signify light shining through and it will grow progressively darker as you move down in the picture.
Apply the background colors to the image. Allow the brush strokes to mix the colors together where they meet, creating a soft mix of color that transitions smoothly from light to dark. Let the background paint dry before you continue.
Paint any items in the background, such as coral or sand. Use a tan color for sand but paint coral and fish with any colors you desire. The underwater world is a colorful one, so you can create bright orange fish and pieces of coral or simple gray-colored background pieces and they will both fit in well with the rest of the image.
Allow the main colors on the background items to dry and then add details like colorful strips or shadows. You should always paint small details last so the main colors of the object do not obscure the fine details.
Paint the focus of the image once the background items dry. The focus of the image can be a diver, a sunken ship, a whale or anything you desire. Paint it with vibrant colors you think suit the object.
Paint highlights and shadows on the focus of the image once the paint dries on its primary colors. Add smaller details as well.
Cover the entire painting in a light blue semi-transparent glaze for an added underwater effect. Cover your image in spay-on clear coat sealant to make the image last longer. Use acrylic paint because it dries quickly and it is easy to paint over your mistakes.