In the western Church this depiction of the face of Christ on cloth is connected to the story of Veronica (which, by the way, means 'true image') who offered her veil to Jesus to wipe away the blood and sweat on his face as he carried the cross to Golgotha.
The moment of the process which was most moving for me was the step in which one has to bring themouth very close to the surface of the icon without touching it. Then a deep breath is taken and breathed heavily on to the icon, the same way you do when cleaning eyeglasses. This act of breathing hot, moist breath onto the icon places just the right amount of moisture on the surface of clay and glue mixture that has been painted onto the places that will receive the tissue paper thin gold leaf. It must be done over and over again because you can apply only about a square inch or so of gold at a time. As I breathed on the halo of Christ's image it felt as if I were breathing life into Him, bringing Him alive. I remembered the priest forcefully breathing the words "Hoc est enim corpus meum," (This is my Body) over the elements of bread and wine in the Latin Mass. And I connected with the charism at the heart of my own contemplative life, the call to be a "living memory" of Jesus Christ, to be His life in this world.