Processing of the archive began prior to 2008 by Museum staff. Processing was completed by Elizabeth Ehrnst in 2011. The finding aid was edited by Laura Ward in 2017.

In 2020, item level correspondence records from MS.6 were exported out of CONTENTdm for import into ArchivesSpace. This correspondence contained three different legacy unique ID systems, all using a three-part alpha-numeric system in the following format: MS-XXXX-###, in which the second section usually referred to the initials of the correspondent and recipient, and the third section used sequential numbering to uniquely identify the correspondence, and generally (but not perfectly) numbered the items so as to place them in chronological order.

The bulk of the materials fell under correspondence from Georgia O'Keeffe to Maria Chabot, with the unique IDs of MS-GOMC-001 through MS-GOMC-332. In addition to correspondence from O'Keeffe to Chabot, this ID system also contained 2 letters from Chabot to O'Keeffe, a letter from Mabel Ludlum to Chabot, Chabot to Ludlum, American Place brochures, Modernfold Doors brochure, Museum of Modern Art exhibition invitation, Art Institute of Chicago exhibition invitation, and a Donald Ferguson tour itinerary. While using the MS-GOMC-### sytem for unique identifiers, this set of correspondence used a separate system (formatted RC-2001-002-###, mirroring the accession numbering system) as the titles for the digital objects within CONTENTdm. The last three digits within both the MS-GOMC-### and the RC-2001-002-### systems matched, refering to the same item. [Please note that within this set, some numbers in the sequence were missed (MS-GOMC-124, 127, 160, and 231), and other numbers were duplicated. Among the duplications, items were distinguished from one another with the addition of capital letters: either A, AA, AAA, etc or A, B, C, etc.]

The second system of numbering refers to correspondence from Maria Chabot to Georgia O'Keeffe, with the unique IDs of MS-MCGO-333 through MS-MCGO-370 (the sequential numbering continued from the GOMC set). The digital objects within this set had titles of MS-MCGO-###, and did not use the RC-2001-002-### system.

Finally, the third numbering system contains correspondence primarily from Alfred Stieglitz to Maria Chabot, with unique IDs of MS-ASMC-001 through MS-ASMC-024 (it did not continue the sequential numbering at 371, and instead restarted at 001). This set contains one item from Stieglitz to O'Keeffe, with all other items from Stieglitz to Chabot. Like the second set, the digital objects in CONTENTdm for this set had titles of MS-ASMC-###, and did not use the RC-2001-002-### system.

During the process of exporting correspondence out of CONTENTdm and importing into ArchivesSpace, the decision was made to retain the legacy IDs in the format of MS-XXXX-### instead of assigning each a unique accession number for two main reasons. 1: Photographs from MS.6 already had item-level records in ArchivesSpace WITH accession numbers assigned, from RC.2001.2.1 through RC.2001.2.380. This means that the first set of correspondence, in which accession-formatted titles were given to digital objects in CONTENTdm, would need an accession number assigned that would conflict with the digital objects' titles. This would create confusion, as each item from that set would have two legacy numbers and one accession number that conflicted with the legacy numbers. 2: The physical letters were previously numbered with their legacy ID number on the recto, often in the viewer upper left corner. By maintaining the legacy IDs, the numbers on the physical items will match the unique ID.

Therefore, correspondence in this collection retains its legacy IDs, recognizable by the format MS-XXXX-###. Photographs in this collection are assigned accession numbers, formatted as RC.2001.2.XXX (without leading zeroes).