Install Python

You have to check one non-default option when installing Python!

Download the Python installer from python.org.
Check the Add Python to PATH option on the very first screen.
Open a console with administrator rights (see FAQ).
Install photon_ptm which will automatically install its dependencies.
```
 pip install photon_ptm
```
Make sure the installation was successful by opening Perseus and selecting the generic Python processing step. The entry for the Python executable should be filled-in automatically and the button should be green.

Updating packages

Open a console with administrator rights and run

pip install --upgrade <package name>

How do I open a console with administrator rights on Windows?

Open the start menu and search for cmd.exe. Right click and select Run as administrator.
Who can I check if Python is correctly installed.
- Open a console
- python --version should give the expected Python version
What if Python is already installed but not in the Path?
- Open the environment variable editor as described here
- Append the Python installation location the the Path. It should read something like: C:\WINDOWS\system32;C:\WINDOWS;C:\Program Files\Python 3.6