Many subjects require painting reflections, from glass and mirrors to water. Reflections can be difficult to paint, but if the right technique is used they are much easier than they may seem. Acrylic paints are easy to use, and have a drying time that is much faster than oil paints. Because some of this method of painting reflections requires wet-on-wet painting, it is more easily achieved with oil paints. It can, however, be effective with acrylic paints if you paint quickly.
Paint the reflected image as usual, using the same colours as the object that is being reflected.
Determine the surface that the object is being reflected in. A mirror will require a slightly longer drying time before continuing than water. Glass will fall somewhere in between, depending on the distortion that the thickness and curvature of the glass would cause.
Allow the paint to dry for up to five minutes if the reflection is in water or is otherwise heavily distorted. Lengthen this to five to ten minutes if the reflection will not be distorted much. If the reflection is in a mirror, the image should be allowed to dry for at least 30 minutes before continuing.
Mix a thin glaze from a grey-toned paint and acrylic fluid or glazing medium. This should be, at most, one part paint to every five parts medium. A thinner glaze may be preferred. Water can be used to thin acrylic paints, but water can weaken the paint pigments so mediums are always preferred.
Dip a clean, soft brush into the grey glaze and cover the entire surface the image is reflected in, including the image. This technique may take practice, because the brush should barely touch the surface. You can add ripples and distortion by adding more pressure to the brush and disturbing the paint more.
Allow to dry for at least one hour before touching.