As a portrait artist, I can attest to the difference between drawing a person's portrait in graphite and painting their portrait. When painting a person's portrait, you are doing more than just capturing their likeness. Through the use of color and the texture of the paint you have the unique ability to capture their character as well. As you study art, you should become familiar with various styles in painting and explore all of them. This not only helps you learn the differences in painting styles first-hand, it also helps you to learn and adapt your own style. There are many mediums for you to choose from (watercolor, acrylic, and oil paints) and each medium offers a wide range of uses. When you are painting portraits for fun rather than through a commission, it is easier to choose the medium based on your knowledge of the subject. However, in the real world of portrait commissions, until you have established a reputation, the person commissioning you already has a medium in mind or a tight budget that dictates which to use.
If you are fortunate to be able to afford a studio with all the proper lighting and props needed, painting from a live model in front of you is ideal. There will be times when you are doing commissions as gifts for others or they may be out-of-state making this either too expensive for traveling or just not possible at all. You may be forced to work from photographs and this becomes more of a challenge. How can you capture a person's likeness and deliver a true portrait when you haven't met the person let alone talked to them and witnessed first-hand how they laugh and the way they carry themselves?
When this is the case I request several photographs and use every one. I interview the person who knows them best and is commissioning me and ask them questions such as "what is their best feature?" It is also important to note the color of their eyes, hair, and skin. One photograph I request is of a studio shot showing them at their finest and the others are snap-shots taken when they are relaxed and having fun. In doing this, I am not just copying another artists interpretation of them but creating one of my own the same as though they were sitting in front of me. (This also saves you from inadvertently violating copyright laws.) Now, the good stuff
1. Composition. Your portrait will succeed or fail through the position you have it on your canvas and if you are painting from a live model, you only have one shot.
2. Drawing your subject is key to any painting - portrait or otherwise and should not be overlooked. The key to every successful portrait is to map out all of the significant landmarks ahead of time right on the canvas.
3. Learn when and where to simplify. Beginning artists have a tendency to want to simplify that which is challenging to them and pass it off as artistic license.' Hands are the biggest. If you completing a full-body portrait, don't just simplify at random. Know when and where it is appropriate.
4. Understanding light. One mistake that is often seen in the amateur portrait is the use of hard lines to determine a person's features: too many sharp edges delineating the nose, hairline, jaw etc. This stems from a person drawing what they know and not how they are seeing the light on these features. An easy description would be drawing each individual tooth in a person's smile. If you are tempted to paint every eyelash and every strand of hair, don't.
5. With light comes shadow. Understanding the differences of shadow can make or break your painting and should not just be painted simply as flesh tones with black added.'
6. Understanding color. Every color has hue (name of the color: i.e. red), value (lightness or darkness) and intensity (strength or saturation). Before you start adding color into your paintings you should understand these and use them accordingly. Once you understand these, you can use any hue as long as the values are correct.
7. Know when to stop. This is probably the hardest stage in any painting. The moment you feel that you have captured your subject, stop. Unless you have adopted a realist style where every button and bead needs to be painted then it's okay to stop at suggesting them from time to time and walk away from the painting when you feel it's finished.