The artists and workmen responsible for decorating the tombs used a variety of implements in wood, metal and stone in different stages of the process. After cutting the tomb in the limestone bedrock, the walls were smoothed with copper and bronze chisels. Any cracks or imperfections were filled with plaster. A uniform layer of plaster was applied on the walls with flat tools called floats to assure the finished surface was completely smooth. When the surface was ready, a grid was traced on the walls by means of strings dipped in red paint.
Then actual decoration began. The tools used to carve reliefs included bronze chisels, wooden mallets, and stone blades. Paint was applied with brushes made of vegetable material, like reeds and bunches of grass. For the ceiling decoration and decoration high on the walls, scaffolding was mounted in the tomb.
The most common colors used in decorating the tomb were red, yellow, green, blue, white and black. The pigments were derived from vegetable and mineral sources. The minerals often came from a nearby wadi known today by locals as the "Valley of Colors."
A popular belief is that the red pigment used by the Egyptians was red ochre, but this is incorrect. Ochre is yellow naturally and only turns red when burned or calcined. Ochre normally contains between ten to twenty percent iron oxide. The reds of the Egyptians contain more than fifty percent iron oxide, and its orange/red hue marks it as being hematite.
All of the yellows used in ancient Egypt were made of the native ochre, a clay stained with iron rust.
The pigment is composed of copper-bearing wollastonite, also called green frit.
The Egyptian blues range from a light sky blue to a dark ultramarine. The principal blue pigment of ancient Egypt was an artificial frit consisting of a crystalline compound of silica, copper, and calcium. This was made by heating together silica and a copper compound (generally malachite).
White pigments are among the earliest painting materials, in use since the Predynastic Period. Calcium carbonate and calcium sulfate (gypsum) were the only two white pigments known.
The black pigment was almost always carbon, obtained as soot, probably scraped from the bottom of cooking vessels.
Once tomb walls had been carved and smoothed, a layer of lime plaster of varying thickness was applied as a final surface. Specialists known as "outline draughtsmen," probably working from some sort of copybook, laid out the actual decoration. Because some royal tombs were left unfinished (KV 14, KV 15, KV 17, KV 57), we are able to follow this decorative process. One of the best examples of such an unfinished tomb is KV 57, the tomb of Horemheb, where several stages of the work are preserved in the burial chamber. It seems that several different activities were simultaneously carried out in different parts of the chamber or even different parts of a wall. Some workmen might have been smoothing a wall while artists were painting another.
A series of preliminary or first draft drawings were made, usually in red ink, overlaid by the final, corrected version in black.
An innovation in royal tomb decoration technique, first found in KV 57, although long used in private tombs, was to carve figures and texts in either sunk or raised relief. Carving raised relief was the more time consuming process, and involved cutting away the surface surrounding the figure or text so that the figure was raised above the background.
Details, such as modeling of musculature or features of costume, then could be carved on this raised surface. Raised relief was most often used where the quality of stone was good and the surface needed little or no patching. Sunk relief began to be used regularly from the reign of Merenptah (KV 8) onward.
Once the figures were carved, the final step was to paint them. If time was short, walls could be decorated with flat, painted figures and texts, applied either directly to the wall or to its plastered surface. This technique was the preferred one in earlier royal tombs and was prevalent in private tombs of the New Kingdom.
After the preliminary layout was done, the artists filled in the outlined figures with red for flesh parts, white for clothing, and black for hair, using thick strokes along the inside edge of the outline and filling the interior with a preliminary coat of white paint, to be filled in later with other colors. They then added background color around figures. Finally, they added details in black as well as text and other colors on the red and white parts of figures. A good example of this process can be seen in burial chamber J of KV 57. In KV 15, only red and yellow paint had been applied.
The intended final form of the decoration of burial chamber J in KV 57 can be ascertained by the finished decoration in well chamber E and chamber I. There, painted raised relief figures and texts on a blue background show the king being received by deities in the netherworld. The ceiling is decorated with a grid work of yellow five-pointed stars on a dark blue or black background symbolizing the night sky.