Partifi.org is a "free and automated tool for creating parts from music scores." This tool was created by those who seek to support and encourage the study and performance of early music who found that instrumental parts were often not readily available. Not only can you upload your own score PDF, you can import public domain scores from IMSLP or browse the "publicly accessible library of user-contributed parts".
If you upload scores and create parts from your own PDFs, please be aware that you should only do this for works for which you hold the copyright. If it is possible to purchase the parts you need, do not use Partifi to create new ones. Also, don't forget to check the Library to see if we have parts you can check out either in print or to download from Library Music Source.
How it works
You can search Partifi to see if the parts you need are already there.
If it's not, you can upload your own PDF or one from IMSLP.
Once you've done that, "Partifi attempts to automatically identify the position of each line. For optimal results, you may need to add, delete, or reposition the generated segments."
The next step is to "Preview the parts for accuracy. At this stage, you can combine two or more parts into a single one (e.g., “violin I” and “violin II”), and add additional page breaks to avoid awkward page turns."
The final step is sharing. "To distribute the partified score, simply share its download link. Be sure to respect the copyright laws of your country. To later edit the parts, add the score to your “favorites” or bookmark the score's admin page. If we determine a score to be in the public domain, we may add the score parts to the Partifi library as a service to the music community."