素描基礎proko（全集） 肖像繪畫教程 3-16：嘴唇的解剖結構

探討東西方哲學 理解宇宙的神祕奧祕 Hello and welcome to Proko. My name is Stan Prokopenko. Today we're learning about the lips. Lips are very expressive. There are many muscles working together to pull on the various parts of the lips. Also, it's the only feature that involves bone movement. Let's start by talking about the basic forms. The tooth cylinder that fits right between the nose and chin can be simplified into a bloated tunican. By bloated, I just mean that the wall of the cylinder curves out rather than being flat. This comes into play when looking at the lips from an angle other than straight on. The bloated tunican affects the surface forms of the lips. The center line of the lips gets pushed outward, and when viewed from the top or bottom, the lips wrap around the cylinder. Notice that from this angle, the corners of the lips are actually lower than the bottom of the bottom lip. Try to avoid drawing the lips as if they were on a flat plane. The major planes The major planes of the lips are very simple. They are very much like a staircase of three steps from the chin to the base of the nose. In fact, if you look at the head from profile, the entire front of the face is like a staircase. The major planes alternate from top plane to bottom plane. When drawing from a front view, this staircase is usually indicated by alternating dark and light shapes. Dark light, dark light, dark light, dark light. Now let's go over a little bit of anatomy. I'll probably go into more depth on the anatomy in a future series. I plan on covering facial expressions, and the anatomy is important to understand for that. For now, let's just take a little peek. The red portion of the lips and the part directly above and below is called the orbicularis oris. It originates at the corners of the lips called the nodes. These nodes are visible as bumps since so many muscles meet and overlap here. In this simplified diagram, you can see that there are a lot of muscles that attach around the orbicularis oris and pull on it to form various expressions. The orbicularis oris can also tighten to form an O, or to blow a kiss. The lips attach to the tooth cylinder at the base of the nose and the top of the chin. Moving on to the minor forms. The top lip has three forms, and the bottom lip has two. Think of these forms as squishy little pillows. The rounded form in the middle of the top lip, called the tubercle, is shaped like a heart and wedges between the two forms of the bottom lip. When looking at the lips from an angle, these forms overlap each other, adding depth. When drawing a foreshortened object, I always look for overlapping lines to show a form is in front of another. Overlapping forms are indicated by T intersections. The lower left overlaps the tubercle, the tubercle overlaps the lower right, the lower right overlaps the top right, and the top right overlaps the far corner. The local value of the red portion is different from the local value of the skin. The relationship depends on the race of the person. With darker skin, the lip could be lighter, and with lighter skin, the lip could be darker. If the person is wearing lipstick, that would change the local value of the lips. Because the lips have a bit of moisture, the highlight will appear brighter and sharper than the highlights on the skin. Unless, of course, the skin is also wet. When shading the lips, pay attention to the minor plane changes of both the top lip and bottom lip. The darkest tones will usually be around the crease, corners, and core shadows at the top of the top lip and bottom of the bottom lip. This upper region of the lips usually has a gradation, revealing the rounded, tuna-can-shaped tooth cylinder underneath. In the middle of the upper lip region is the philtrum. It's a concave depression composed of two planes. The darker plane of the philtrum will be on the opposite side of the dark on the overall upper region. The edge of the upper lip has a small ridge, or a top plane that sometimes catches light. I try to play down this effect to avoid drawing a white outline. This could look like a milk mustache. The ridge that borders the bottom lip is steep in the middle and softer on the outsides. The lower lip region has two pillars that angle inward towards the top. Together, these two pillars form an arch under the bottom lip, which is often in shadow since it faces downward. At the corners of the lips, there are bumps where many of the muscles connect. The volume of the nodes is similar to a bean. When shading, make sure to think of it as a rounded form that pinches inward. The roundness of the bean creates a soft edge at the outside and top. The pinch creates a sharp edge at the inside and bottom. That's it! Thanks for watching, and thank you for being a premium member. If you're enjoying the course, don't be all selfish. Tell your friends. And if you want to subscribe to the Proko newsletter, go to proko.com slash subscribe. Bye bye!