Even if you don’t understand a word said, the video is well worth watching to get an idea about how Haltadefinizione created the HD file used for the Shroud 2.0 app. (Also see Neat Trick with the Shroud 2.0 App (including comments) if you want to save HD images for detailed examination)
From the company’s website:
Haltadefinizione® was in charge of the shooting of the cloth of the Shroud between January 22nd and 23rd 2008.
On the occasion of the extraordinary opening of the preservation system ordered by Cardinal Poletto, the then Custodian of the Holy Shroud, in agreement with the Holy See, Haltadefinizione® was authorized to acquire high definition (HD) digital images of the Shroud. These HD images represent a milestone in the history of the Shroud. During the shooting of the Shroud, the entire surface of the cloth was captured for the first time using advanced HD photographic techniques. A process very similar, on a small scale, to that used for topography.
The image reached an unprecedented optical resolution not visible to the naked eye, allowing clearly to distinguish the individual elements that compose the cloth: elements of a diameter of a few hundredths of a millimeter.
[ . . . ]
Therefore, 1649 photographs were taken, each of which represents the area of the size of a business card, creating a single image of 12 billion points stored in one file of 72 Gigabytes, equal to the contents of 16 DVDs.
In order to reproduce the entire image at its maximum enlargement, a humongous cloth would be needed, 68 meters wide and 18 high.