Sketching and Line Drawing
When painting a thangka, after preparing the frame, canvas, and tools like various paintbrushes and compasses, you enter the thangka painting process. Its typical steps include: sketching, coloring, line outlining, gold polishing, eye-opening, etc. Sketching mainly consists of steps like squaring, positioning, and line drawing.
Principles of Sketching
Sketching is called "Jiangbeng" in Tibetan. The core principle of sketching is to strictly follow the iconometric measurements for Buddha images. Iconometric measurements mean that the central figure or Buddha in the thangka must be drawn with a proportion grid based on specific proportional relationships; other elements can be arranged freely, but symmetry is generally maintained. The common measurement units for thangkas are: Tuo, Suo, Gangba, and Nai.
In actual painting, the eye width of the central figure or Buddha image is defined as one Suo. The conversion relationships between these units are: 1 Tuo = 12 Suo, 1 Suo = 4 Gangba, 1 Gangba = 2 Nai. These units are not actual physical sizes, but fixed proportional relationships—artists can scale them freely as needed. Texts such as Condensed Sutra of the Kalachakra, Jiezang Kangliu Sutra, Wish-Fulfilling Pearl of Iconometric Measurements for Sakyamuni Buddha’s Form, and Source of Knowledge on the Methods of Painting and Sculpting Sacred Images specify detailed dimensions for Buddha images, incarnate and sambhogakaya forms of Buddhas, as well as figures like yidams, wrathful deities, bodhisattvas, and dharma protectors.
Steps of Sketching
As specified, the first step of sketching is squaring and positioning. Squaring typically uses the red string mentioned earlier—called "Touge" in Tibetan: use "Touge" to draw the diagonals of the canvas, take their intersection as the center, and use a wooden compass to draw circles 1/4 the length of the diagonals outward, getting four new intersections. Then take these four points as centers to draw more circles; the overlapping circles form four upper-lower and two left-right intersections. Connect these points in the up-down-left-right directions to get the central vertical line of the entire canvas and four neat borders—this completes squaring.
Next, position the main Buddha: connect the intersections formed by the four circles on the upper-lower and left-right center lines into an oval shape. This oval is the area for the main Buddha’s body and aura.
Steps of Line Drawing
Once the main Buddha’s position is fixed, strictly follow the iconometric dimensions of Buddha images specified in Buddhist scriptures, grasp the proportional relationships, and draw a proportion diagram. Then carefully connect relevant points in the diagram to outline the Buddha’s shape. This outlining process is line drawing, which requires at least three passes:
- The first pass uses a charcoal pencil, with lines that are even and smooth;
- The second pass revises and refines the first, still using a charcoal pencil;
- The third pass finalizes the line sketch, usually with a pencil, and the lines should be more precise.
