The :command:`specgrid_to_photgrid` tool convolves a spectroscopic grid with a passband to make a photometric grid, writing it to a :f-schema:`photgrid` file. It accepts the following command-line arguments:
.. program:: specgrid_to_photgrid
.. option:: <specgrid_file_name> Name of input :f-schema:`specgrid` file.
.. option:: <passband_file_name> Name of input :f-schema:`passband` file.
.. option:: <photgrid_file_name> Name of output :f-schema:`photgrid` file.
Note that it's not always necessary to create :f-schema:`photgrid` files, as MSG can convolve with passbands on the fly (as discussed in the :ref:`photometric-colors` section).