The Bibliotheca Hertziana – Max Planck Institute for Art History has published a new resource called the Navigator (https://nav.biblhertz.it/), to complement the data curated for the online catalogue (https://foto.biblhertz.it/).[1] 

This new research tool offers direct access to digitised versions of around 600,000 analogue photographs in the best available format.[2]
Users can browse the collection using either the visual presentation of the collection or the classification tree. Alternatively, the text search function can be used to search all the labels on the photographs as well as those on their folders, boxes and drawers. 
The help page (https://nav.biblhertz.it/hilfe.html) describes the application’s features and the data, which are subject to continuous updates. 

The application is optimised for accessibility and for mobile devices, and enables users to browse the collection’s contents, replicating its physical organization for photographs that have not yet been catalogued. It also enables users to use contextual information to find relevant content in the different parts of the collection.  

Indexed data includes texts obtained through hand transcription, optical character recognition (OCR) and AI-assisted transcription. Although these methods are imperfect, they allow quick access to information.
 
The search function provides direct access to the contents held in the Navigator. It also provides direct access to the contents held in the Catalogue. Even images without metadata are presented with their label, where they are available, and all annotations on the recto and verso are presented alongside the catalogue data where present.

By expanding the digital range of the Photographic Collection[3] of the Bibliotheca Hertziana with the structured availability of the archive, the Navigator enables searches in a large portion of the collection from outside the institute's premises. Prioritising photographs over the accompanying metadata and utilises the collection's ordered structure as a means of access and retrieval. 

Link: https://nav.biblhertz.it

[1] The same records are also available with different functionalities in https://bildindex.de/  https://arthistoricum.net and https://artresearch.net.
[2] To respect copyright, the size and resolution of images that can be accessed from outside the Bibliotheca Hertziana network are limited. However, this applies only to images that are not expressly available.
[3] This includes also, for example, curated datasets for machine learning available in the open source repository Edmond (https://edmond.mpg.de).