Portrait painting is a challenge, particularly if your goal is a high level of realism. Begin with simple, straightforward poses as you adjust to matching the symmetry and subtle nuances of the human face. As you get used to painting portraits, you may grow into more challenging poses. The other great difficulty of portrait painting--one that may often be overlooked by first-time portrait painters--is capturing the personality and subtle qualities exhibited by the subject. This is something that comes with time. Getting to know your subject will help with this aspect. Acrylics are a water-soluble medium, great for first-time portrait painters because their handling can more intuitive than oil or water colour. Acrylic's fast drying time, however, may pose a challenge for colour blending.
Begin by selecting a subject. You may choose to paint a live person as your subject, although for a first-time painter, it will probably be easier to paint from a photograph. This article will assume that you will be painting a bust only--that is, a head and shoulders.
Mix the skin tones of the face. You should start with a palette of the primary colours red, yellow and blue, plus black and white. For the sake of realism, do not rely on premixed skin tones. Do not mix too much, especially at first. Skin tones are tricky to match and acrylic paint dries very quickly. If you mix too much of the wrong colour, the paint will quickly be wasted.
Thin the paint with a little water and apply it to the canvas in a wash. Paint the features first very generally and without any details. The face will be a skin-toned oval, the shirt will not feature shadows or highlights. Quickly, and without regard for neatness, cover the entire canvas.
Mark with fast, light strokes the position of the eyes, nose and mouth with a medium to large round brush. Step back from the painting and examine the position of these features. Alignment of the eyes and nose is a common problem, especially for first-time portrait painters.
Use a slightly smaller round brush to begin filling in the facial structure with greater detail. Use a thicker coat of paint if you want, but keep in mind that acrylic's fast drying time may leave you wanting to thin the paint with water for blending. Begin to build up a respectable layer of paint. Although acrylic's fast drying time is a disadvantage when it comes to blending, it is never more handy than when you find yourself trying to cover mistakes. Block in shadows and the shine on the hair. Add some detail to the clothing, like shadows and creases in the cloth.
Use a detail brush to add more minute details over the larger, more general shapes of the eyes, nose and mouth.
Go back in with the medium-sized round brush and blend the finer details with the larger structural portions of the face.
Leave the painting for a while and return when some time has passed, so that you may look at the painting with fresh perspective. This is the time for touch-ups and details.
One trick to try if you think something is wrong with the portrait but you're not sure what, is to look at the canvas in a mirror or--better yet--turn it upside down. Small mistakes, misjudgements and inconsistencies will often jump out when you look at the painting from a fresh perspective. Some artists will even correct the problems while the painting is upside down. This is especially useful with portraits because the slightest misplacement of an eye or nose will throw off the entire face.