"Tengujo can be made so thin that, at a certain point, it is too insubstantial for even the most gentle, decorative uses."

"At the width of a couple of kozo fibers, the paper becomes as thin as the wings of a mayfly. Only one use remains then: paper conservation. Trying to aggressively mend a document is risky because long-term chemical and physical effects are highly variable and relatively unknown. 'The more and more I am in this field, I feel that I should do less and less,' Ms. Choi said. So, as far as reinforcement material goes, the thinner the better.... The width of this thinnest tengujo is the same as the diameter of a single kozo fiber: 0.02 millimeters.... Slicing a 3-millimeter strip of Hidaka Washi tengujo with an ethanol-activated adhesive brushed onto one side, Ms. Choi gently covered an imperfection in Pinckney’s yellowing page. With a little push, the papers melted into each other. From a normal reading distance it looked as if nothing had been done, but under close examination you could see tiny strands of kozo gripping onto the ink....."

From "The Thinnest Paper in the World" (NYT).

Kozo is material — stems — from mulberry trees.

Choi is Soyeon Choi, "the head paper conservator at the Yale Center for British Art."

Pinckney is Eliza Pinckney, who was "a prominent American agriculturalist" and who wrote that letter in 1753.



From her Wikipedia article:

Eliza was 16 years old when she became responsible for managing Wappoo Plantation and its twenty slaves, plus supervising overseers at two other Lucas plantations, one inland producing tar and timber, and a 3,000 acres (12 km2) rice plantation on the Waccamaw River. In addition she supervised care for her extremely young sister, as their two brothers were still in school in London. As was customary, she recorded her decisions and experiments by copying letters in a letter book. This letter book is one of the most impressive collections of personal writings of an 18th-century American woman. It gives insight into her mind and into the society of the time.

From Antigua, [her father] Col. Lucas sent Eliza various types of seeds for trial on the plantations. They and other planters were eager to find crops for the uplands that could supplement their cultivation of rice. First, she experimented with ginger, cotton, alfalfa and hemp. Starting in 1739, she began experimenting with cultivating and improving strains of the indigo plant, for which the expanding textile market created demand for its dye. When Col. Lucas sent Eliza indigofera seeds in 1740, she expressed her "greater hopes" for them, as she intended to plant them earlier in the season. In experimenting with growing indigo in new climate and soil, Lucas also made use of knowledge and skills of enslaved Africans who had grown indigo in the West Indies and West Africa.

After three years of persistence and many failed attempts, Eliza proved that indigo could be successfully grown and processed in South Carolina. While she had first worked with an indigo processing expert from Montserrat, she was most successful in processing dye with the expertise of an indigo-maker of African descent whom her father hired from the French West Indies.

Eliza used her 1744 crop to make seed and shared it with other planters, leading to an expansion in indigo production. She proved that colonial planters could make a profit in an extremely competitive market. Due to her successes, the volume of indigo dye exported increased dramatically from 5,000 pounds in 1745–46, to 130,000 pounds by 1748.[4] Indigo became second only to rice as the South Carolina colony's commodity cash crop, and contributed greatly to the wealth of its planters. Before the Revolutionary War, indigo accounted for more than one-third of the total value of exports from the colony....

This letter book is one of the most complete collections of writing from 18th century America and provides a valuable glimpse into the life of an elite colonial woman living during this time period. Her writings detail goings on at the plantations, her pastimes, social visits, and even her experiments with indigo over several years. Many scholars consider this letter-book extremely precious because it describes everyday life over an extended period of time rather than a singular event in history....

There's a Pinckney Street in Madison, Wisconsin because of her son, Charles Cotesworth Pinckney, who was one of the founders of the United States Constitution.

You can read some excerpts from Eliza Pinckney's letter book here. Example (from May 1742):

Wont you laugh at me if I tell you I am so busey in providing for Posterity I hardly allow my self time to Eat or sleep and can but just snatch a minnet to write you and a friend or two now. I am making a large plantation of Oaks which I look upon as my own property, whether my father gives me the land or not; and therefore I design many years hence when oaks are more valueable than they are now — which you know they will be when we come to build fleets.  I intend, I say 2 thirds of the produce of my oaks for a charity (I'll let you know my scheme another time) and the other 3rd for those that shall have the trouble of putting my design in Execution. I sopose according to custom you will show this to your Uncle and Aunt. “She is [a] good girl,” says Mrs. Pinckney. “She is never Idle and always means well.” “Tell the little Visionary,” says your Uncle, “come to town and partake of some of the amusements suitable to her time of life.” Pray tell him I think these so, and what he may now think whims and projects may turn out well by and by. Out of many surely one may hitt. . .