The Fototeca in the archives of the Veneranda Fabbrica del Duomo di Milano is made up of over 40,000 phototypes created between the second half of the 19th century and today using various photographic techniques.
The Fototeca Vecchia Grande section is one of the oldest and contains 269 negatives on large glass plates which primarily document the Cathedral, some drawings, and archival documents.
The photograph that we are showing you, dating from the first half of the 20th century as can be inferred by the clothing being worn, is printed from a large negative and, more precisely, is a “silver nitrate gelatin” print, a photographic technique that already in 1870 had begun replacing the use of albumen. The image is an accurate depiction of the tramway traffic in Piazza del Duomo; the circulation of public transportation around the Cathedral was allowed until 1972, the year in which certain restrictions were enacted by the Commissioner of Transportation-Traffic and Accessibility, engineer Luigi Ferrari, in agreement with Mayor Aldo Aniasi.
Beginning at 10am on 8 September 1972 the “closing of Piazza Duomo to traffic” measure was put into effect until further notice, following an official letter by the Prefect of Milan, Dr. Libero Mazza. The measure required the Municipal Authorities to immediately prohibit circulation of vehicles around the Duomo and the A.T.M. management to enforce a reduction in speed along the overlooking portion of the tramway and of the underground on the stretch of track along the monument in order eliminate, as much as possible, the vibrations caused by the passage of trams and trains.
This notice came after a public announcement made on 7 September 1972 by the Prefectural Commission for the Stability of the Duomo :
“The scrupulous attention with which the technicians of the Fabbrica del Duomo constantly monitor the stability of the Monument helped to reveal signs of a structural deterioration in 1962, identified through the existence of numerous cracks in the blocks of Candoglia marble which comprise the thick peripheral crust of pillars and, in particular, the four pillars that support the Tiburio, on the cupola of which is erected the spire of the Madonnina”.
Some of those "signs" were long-standing, while others seemed much more recent, therefore exceedingly accurate measurements were requested, to the millimetre, aimed at identifying any potential movements at the base of the Duomo's pillars, and any small movements in the foundation that indicated a lowering of the groundwater beneath the city were recorded. Therefore, in 1972, it was the Fabbrica that had accurate level readings of the city centre. Following several load tests, the need to restore some pillars was demonstrated (carried out in 37 days) and the detachment of several marble flakes from the pillars in the apse indicated the existence of “a state of tension difficult for the material to tolerate”. One of the causes identified by the commission were the vibrations of traffic around the Duomo. In order to minimize this effect, in addition to the measures described above, it was requested that visits to Cathedral's apse and transept be limited.
Since 1387 the Veneranda Fabbrica del Duomo has always striven to “heal” and safeguard the monument, in order to guarantee it “a long life through the centuries”. This photograph of the Duomo represents Milan's history, the daily life of each of its citizens, and chronicles an important evolution.
 According to the minutes from 23 January 1986, the current Prefectural Commission was established by decree of the Prefect of the Province of Milan (prot. N. 19.1/4452-Gab. dated 30 October 1985) and is assigned “an advisory role in the event of exceptional circumstances or other situation that could impact the stability of the Cathedral”. The members of the commission are appointed by the Prefect at the behest of the Administrative Council of the Veneranda Fabbrica and oversee an important collaboration between the Fabbrica, the Polytechnic University of Milan, the Superintendence, the Lombardy Region - General Management of the Urban Territory and Land Protection, the Municipality of Milan, and the Fire Department.