Mean time to recovery is calculated by adding up all the downtime in a specific period and dividing it by the number of incidents. So, let's say our systems were down for 30 minutes in two separate incidents in a 24-hour period. 30 divided by two is 15, so our MTTR is 15 minutes.

for calculating it, divide the total maintenance time by the total number of maintenance actions over a given period of time. In other words, you need to sum up the time you've spent on the restoration and divide it by the number of restores you performed.

1) Depende del tipo de piezas que pretendas restaurar:

--- siguiendo las Bellas Artes:

a) pintura (diversos soportes)

b) escultura (diversos soportes)

c) arquitectura (edificios enteros o partes de un edificio)

d) literatura (papel básicamente)

e) música (patrimonio inmaterial: sonoro; papel: partituras)

f) teatro y artes escénicas (patrimonio inmaterial)

g) cine (soporte cinematográfico)

(otras artes menores: cerámica, rejería, vidrieras, relojes, orfebrería, vestidos; ámbitos diversos numismática -metales-, filatelia -papel-, sigilografía -sellos-, etc.; nuevos métodos del arte contemporáneo: vídeo, performance, collages, nuevos pigmentos, materiales industriales, arte térreo, arte efímero, etc., etc.)

2) Depende de los procesos de conservación y restauración:

a) limpieza (de madera, de piedra, de papel, etc.)

b) recomposición (reunificación de fragmentos sueltos o desprendidos)

c) adición de nuevos elementos (basados en la investigación, anteriormente existentes y luego desaparecidos por diversas causas: con técnicas de diferenciación entre lo original y lo añadido-restaurado)

d) reencuadernación (libros, manuscritos)

e) reclasificación + presentación (creación de nuevos embalajes o de nuevos contenedores para la obra de arte y mejor presentación de la misma)

Entonces:

1.a. + 2.a = si he de limpiar un cuadro (óleo sobre lienzo; o un icono...), he de saber el tiempo que tardan en reaccionar los pigmentos (óleos, pan de oro, etc.) con los tratamientos de limpieza

1.d + 2.a = si he de limpiar un libro manuscrito del siglo XVII, he de saber cuánto tarda: desmontar la encuadernación (cosido, etc.) del libro; separar los cuadernillos, separar cada pliego y sumergir cada pliego en la solución acuosa determinada (nº de páginas x desmonte+separación+inmersión)

Y así con todo.

PD. No soy matemático, pero me doy cuenta de que las sorpresas en el momento de la conservación y de la restauración son múltiples, continuas y muy variadas (por ejemplo: en la catedral de Valencia, España, en el ábside, limpiaron las bóvedas, y se encontraron unos frescos más antiguos que cualquier otra cosa de la catedral... habían tenido un hallazgo: eso hizo que todo cambiara y que el proyecto se transformara: ya no sería sólo limpieza de las bóvedas, sino conservación de los nuevos frescos, investigación, divulgación, publicidad etc)

Saludos cordiales

fr. Ignacio Husillos Tamarit, ocd.

Hi Dr Olesia Lebedivna . See the following link: https://www.fiixsoftware.com/mean-time-to-repair-maintenance/

See the following link: https://www.atlassian.com/incident-management/kpis/common-metrics

Also see the following link: https://limblecmms.com/blog/mttr-mtbf-mttf-guide-to-failure-metrics/

Kindly see also the following link: https://www.reliableplant.com/mttr-31713

Dear Dr. Olesia Lebedivna ,

When it comes to Manuscript Book Restoration, the time used by a Restorer has no schedule, but it has a soul. The binding covers are cleaned, the wax drops are removed [for centuries they were read by candlelight because there was no other source of Light] with a scalpel and a balm is applied with cotton and tweezers so that the skin recovers its original texture. With the sheets already separated and pressed between blotting paper, the tears in each parchment are healed with very fine dressings, made with very young “calf gut”.

Although today it is somewhat impressive, the making of Medieval Booksrequired a large amount of animal matter, especially bones and skins. In large books such as the Medieval Canticles, each parchment sheet is the entire skin of an animal, so in total the skin of 200 calves or more was used to obtain all the pages. For the smaller Manuscript Books, goatskin was also used or the skin of a cow was divided between three or four sheets. The finer the parchment, the younger the animal, these were very refined and small Manuscript Books and were made with the skins of freshly born calves. For its restoration, the loin is glued with a natural string and pastry gelatin, obtained in turn from cooked and crushed bones, but “natural collagen” can also be used since it tends to adhere as much or more than glue. After so many years, the skin of the Manuscript Book covers is very delicate, which is why their recovery is rarely complete and the damage suffered by the Manuscript Book is almost always observed, but sometimes they are usually replaced by new wooden covers. The sheets that have less consistency are sheathed in transparent plastic so that the pages can be turned without risk of deteriorating their safeguarding, and the remaining sheets are kept uncoated. It is essential to maintain the original appearance of each Manuscript Book as much as possible and the paper should never be sprayed with fungicidesin case they have fungi or bacteria,so it is more convenient to eliminate them in the freezer or in a bag without oxygen, because the fungicides workonly for a time but do not remain on the sheet forever, what is recommended to do is to store the books in an environment without humidity or extreme temperatures. It is always advisable to digitize all content and store it.

There are also in the East the Restoration of palm leaf manuscript:

See the following Scientific Research Papers:

https://brill.com/view/journals/jim/1/1/article-p37_5.xml

https://brill.com/view/journals/qua/46/4/article-p251_2.xml

https://www.cabdirect.org/cabdirect/abstract/20123246079

DOI: 10.1109 / ICCV.2001.937649

for restoration of palm leaf manuscript see:

Chapter Digital Image Restoration of Historical Devanagari Manuscripts

Article A novel binarization technique based on Whale Optimization A...

Thank you very much for your "right response", Dear Researcher friend, Dr. Ignacio Husillos Tamarit