Editing Terracotta (section)

==Properties==
{{See also|Clay|label 1=Clay: Properties}}
Terracotta is not [[waterproof|watertight]], but its porousness decreases when the body is [[Burnishing (pottery)|surface-burnished]] before firing. [[Ceramic glaze|Glazes]] can be used to decrease permeability and hence increase watertightness.

Unglazed terracotta is suitable for use below ground to carry pressurized water (an archaic use), for garden pots and [[Olla#Use in irrigation|irrigation]] or building decoration in many environments, and for oil containers, oil lamps, or ovens. Most other uses require the material to be glazed, such as tableware, sanitary piping, or building decorations built for freezing environments.

Terracotta will also ring if lightly struck, as long as it is not cracked.<ref>{{Cite book |last=Dasgupta |first=Chittaranjan |title=Collection of Essays on Terracotta Temples of Bishnupur |year=2015 |isbn=9789385663109 |language=Bengali}}</ref>

Painted ('''polychrome''') terracotta is typically first covered with a thin coat of [[gesso]], then painted. It is widely used, but only suitable for indoor positions and much less durable than fired colors in or under a ceramic glaze. Terracotta sculptures in the West were rarely left in their "raw" fired state until the 18th century.<ref>Grove, 2, i, a</ref>

===Advantages in sculpture===
As compared to [[bronze sculpture]], terracotta uses a far simpler and quicker process for creating the finished work with much lower material costs. The easier task of modelling, typically with a limited range of knives and wooden shaping tools, but mainly using the fingers,<ref>Grove, 2, i, a; Scultz, 167</ref> allows the artist to take a more free and flexible approach. Small details that might be impractical to carve in stone, of hair or costume for example, can easily be accomplished in terracotta, and drapery can sometimes be made up of thin sheets of clay that make it much easier to achieve a realistic effect.<ref>Scultz, 67, 167</ref>

Reusable mold-making techniques may be used for production of many identical pieces. Compared to [[marble sculpture]] and other stonework, the finished product is far lighter and may be further painted and glazed to produce objects with color or durable simulations of metal patina. Robust durable works for outdoor use require greater thickness and so will be heavier, with more care needed in the drying of the unfinished piece to prevent cracking as the material shrinks. Structural considerations are similar to those required for stone sculpture; there is a limit on the stress that can be imposed on terracotta, and terracotta statues of unsupported standing figures are limited to well under life-size unless extra structural support is added.  This is also because large figures are extremely difficult to fire, and surviving examples often show sagging or cracks.<ref>{{cite magazine|last1=Scultz|last2=Hobson|first2=R.L.|title=A New Chinese Masterpiece in the British Museum|magazine=The [[Burlington Magazine]] for Connoisseurs|volume=25|issue=134|date=May 1914|page=70|jstor=859579}}</ref>  The [[Yixian glazed pottery luohans|Yixian figures]] were fired in several pieces, and have iron rods inside to hold the structure together.<ref>Archived at [https://ghostarchive.org/varchive/youtube/20211211/2T-EG7Bjcig Ghostarchive]{{cbignore}} and the [https://web.archive.org/web/20140414223523/http://www.youtube.com/watch?v=2T-EG7Bjcig Wayback Machine]{{cbignore}}: {{Cite web|url=https://www.youtube.com/watch?v=2T-EG7Bjcig|title=Lecture by Derek Gillman at the Penn Museum, on their example and the group of Yixian figures. From YouTube| website=[[YouTube]] |date=8 August 2011 }}{{cbignore}}</ref>