Good holy reading! Thank you.
A few additional details about the sketch, you might like this... :

...Sister Geneviève, Céline Martin, sister of Saint Thérèse, who painted the Holy Face
THE HOLY FACE OF CÉLINEhttps://crc-canada.net/liens-utiles/archives-de-notre-bulletin/le-pere-eugene-prevost-et-la-devotion-a-la-sainte-face Saint Thérèse of the Child Jesus and the Holy Face died on September 30, 1897. The following March, an exhibit of the Holy Shroud took place in Turin. It is on this occasion that, at the instigation of the Salesian Noguier de Malijay, the King of Italy asked his photographer, Secundo Pia, to take the first photographs of the holy Relic that will make appear, in positive, the true portrait of Our Lord. In 1902, Paul Vignon published his first book
, The Shroud of Christ, illustrated by the photos of Pia. Uncle Isidore Guérin immediately procured it and lent it to his niece Céline, in religion Sister Geneviève, the last of the Martin family to have entered the Carmel.
Let his biographer tell us what happened:
“In the evening in her cell, at the hour of silence, the nun unfolds the planks that reproduce in positive the negative form imprinted on the cloth soaked with aromatics. She remains silent with emotion. “It was indeed my Jesus, as my heart had sensed him... And, looking for the traces of his pains, I followed by the wounds the imprint of the cruel crown of thorns. I saw the blood coagulate in the hair, then flowing in large drops. At the top of the head, on the left, we feel that the crown must have been torn off with difficulty. This effort kept the hair stuck together by blood... So, not being able to contain the feelings of my heart, I covered this adorable face with my kisses and watered it with my tears. And I made the resolution to paint a Holy Face according to this ideal that I had glimpsed. ”
“Sister Geneviève could not take up the task until Easter 1904, and first executed a charcoal drawing. The publishing houses to which she addressed represented that the reproduction would be defective. Better to make a greyness in paint {Grisaille ...First an outline, values, movement in crayon, shades, even black, usually gray; then watercolors. See att. YTube short Td.}. She applied herself there in 1905, till Pascaltime, dedicating all her free time: Sundays, feast days and hours of silence. She worked standing, which was a torment, facing an image, full natural size, of the Face of Christ, striving to follow the least threads of fabric and the corresponding traces. Sacrificing the nap, she was content to lie down in a ball at the foot of her canvas, the last ten minutes, her head leaning on her handkerchief rolled in a ball: what she called “doing the dog”.
She mobilized all Heaven to her rescue, laying every evening brushes and work before the Virgin of the Smile, wearing, when she was alone, her painting before the Blessed Sacrament, as if to subject it to her divine rays. She also interested in St. Joseph, the whole heavenly militia and her own family from up there. When the effort was too hard, she thought of the Painful Virgin at the top of Calvary. During these few months, it happened to her three or four times – whether under the effect of an imagination haunted by her subject or a privilege of choice rewarding such a labor – to see before her, the space of a minute (“it was not the eyes of the body,” she says) “the face of Jesus suffering, of a striking beauty and sharpness.”
“The finished canvas, she carried it to the Blessed Virgin” to give her the first fruits. Then she had the inspiration to consult the Gospel and fell on the verse of St. Matthew:
“All those who were there and who saw what was happening said: This one is truly the Son of God. ” »
...______________
In French.
https://www.youtube.com/shorts/BB5LcyDtam4Lots of results in English btw.
Apparently she used a technique called "Grisaille", an advanced 'aquarelle' technique.