The images in question are from the same Triduum ceremonies (1936) as the Holy Thursday pictures, but show instead the papal ceremonies of Good Friday -- and evidently, since we are speaking of Pius XI, it goes without saying that these are the Holy Week ceremonies from prior to the time of their revision under Pius XII.
(Pius XI seated upon the papal throne in papal mantum, with Cardinal deacons in cappa on either side)
With regard to Pius XII, I would be remiss to not note that the Cardinal celebrant of this liturgy is none other than Cardinal Pacelli, the future Pope Pius XII.
While that is of some interest as well of course -- particularly given that it would be he who would enact the revision of these same ceremonies nearly 20 years later -- more interesting still (and herein lay the greater liturgical rarity to be found in these images) is the quite rare opportunity to see the use of folded chasubles within the context of the papal ceremonies, and upon Good Friday no less.
(Deacon and subdeacon in folded chasubles before the altar of the Sistine chapel. Cardinal Pacelli, the future Pius XII, is seated upon the faldstool on the Epistle side. The Assistant priest in cope is beside him)
(Note the stripped altar and the smaller cross upon the altar; likewise, there is no canopy above the papal throne)
As yesterday, I include a description of the papal ceremonies from The Ceremonies of Holy Week in the Papal Chapel at the Vatican by Francesco Cancellieri. (Take note of the interesting details such as the use of a Greek and Latin choir.)
The candles on the altar and balustrade are yellow; the Pope's seat, the benches of the Cardinals and assistants are uncovered and the maces reversed in sign of mourning.
The Cardinal Penitentiary who officiates this day, the Deacon and Subdeacon, enter in black garments, without censer or lights, to express the darkness spread over the earth by the death of the Creator.
The Pope, habited as at the Tenebrae preceded by the Cross, without his ring, without giving his blessing, enter the Chapel, deposits his mitre and says a short prayer.
The Cardinal celebrant prays at the altar which, being stripped, is emblematic of the nakedness of the Redeemer on the Cross. A chanter sings the prophecy of Hosea; the Tract follows; the Penitentiary reads the prayer; the Deacon sings flectamus genua, the subdeacon Levate and reads a lesson form the book of Exodus. Three chanters sing the Passion according to St. John, the only Apostle who followed his master to the Cross. At the word "inclinato capite emisit spiritum" the Pontiff and all assistants kneel: the Deacon then lays aside the folded chasuble, puts on the stole as a mark of penance, and without asking the blessing, or carrying either lights or incense, he reads the end of the Passion in the ordinary tone of the Gospel.
A sermon is then preached by a minor Conventual who approaches the Pontifical throne and kneeling claims the indulgence of only XXX days saying "Indulgentias Pater sancte" but the Pope answers "Triginta annorum" which is proclaimed at the end of the sermon.
Prayers, Adoration of the Cross
The celebrant laying aside the chasuble receives from a deacon a Cross covered with a black veil which is removed by degrees, and presenting it to the assistants says: "Ecce lignum crucis". The Tenors answer "In quo salus" and the whole choir "Venite adoremus" when all prostrate themselves except the celebrant who, advancing to the Gospel side of the altar uncovers the right arm of the Cross, repeating in a louder voice "Ecce lignum crucis," the choir responding as before. At the centre of the altar he uncovers it in full, saying in a still louder tone, "Ecce lignum crucis"; the same response being made for the last time; it is then carried to the steps of the altar, the Pope and all present kneeling.
When the Pontiff has resumed his seat, his shoes are taken off, the cope and mitre are laid aside; and following by the assistant Bishops he prays before the Cross, and orders his attendant knight to depose his offering which is brought in a purse of red damask silk fringed with gold.
The choir intone the Improperia composed by Palestrina... At the end of each Improperium is sung the "Trisagion", Sanctus Deus, Sanctus fortis, Sanctus Immortalis, miserere nobis, by one choir in Greek and by another in Latin.
The Cardinals, Bishops and other attendants proceed to the adoration: the candles are lighted and the Cross is replaced on the altar. The Improperia finish with the adoration.
Procession to the Pauline Chapel
The chanters lead to the "Sala Regia" and stop at the door of the Pauline chapel... the subdeacon, with the Cross uncovered, between two Voters of the signature carrying lights; the Cardinal deacons, priests and bishops; the Cardinal celebrant, and the Sovereign Pontiff, followed by the officers of his court, and Generals of religious orders. When arrived at the chapel, ten candles are lighted, the Pope kneels and prayers before the holy Sacrament. Monsignor Sacrista received the key from the celebrant, opens the Sepulchre while the Pope places incense in the thurible, and thrice incenses the boat.
Monsignor Sacrista takes the box from the Sepulchre; the Sacrament is put into the chalice, covered with a veil, delivered to the Cardinal and then to then the Pope who places it under a corner of the veil hanging over his shoulders, and the procession returns to the Sistine chapel.
The Assistant Bishops and Protonotaries supporting the canopy are in attendance at the door of the Pauline chapel to receive the Sacrament carried by the Pope...
The celebrant receives the chalice, places it on the altar, and incenses the host, while the Pope, remaining uncovered, puts incense into the thurible. The Deacon pours wine, the subdeacon water, into the chalice, which is placed on the altar; the celebrant says "in Spiritu humilitatis" and turning to the people invites their prayers, "Orate fratres", recites the Pater noster and sings the "Libera nos quaesumus Domine."
All kneel, the Pope goes to the "faldistorium" and there remains till the end of the communion. The Celebrant holding the Sacrament over the paten divides it, puts one particle in the chalice.... then striking his breast, he repeats three times Domine non sum dignus and Corpus Domini nostri at the communion; he then takes another piece of the consecrated particle, with the wine of the chalice, omitting the other prayers.
All rise; the Pontiff resumes his mitre, the Celebrant kneeling says, after purifying the chalice, "quod ore sumpsimus Domine para mente capiamus, et de munere temporali fiat nobis remedium sempiternum", then kneels to the Cross and returns to the vestry.
I hope you have found these images and the corresponding descriptions to be of some liturgical and historical interest.
Thanks again to my friend who found these in an Italian periodical from the 1930's and took the time to scan them.