Chemiosmosis in chloroplasts is primarily driven by the translocation of protons from the thylakoid lumen to the stroma. This is the main process that generates the proton motive force used to drive ATP synthesis.

However, there is another, less significant, movement of protons that also contributes to the proton gradient:

* From the intermembrane space to the stroma: This happens through proton leak channels in the inner chloroplast membrane. This movement is less efficient than the primary one across the thylakoid membrane, and its contribution to the proton gradient is relatively small.

It's important to remember that chemiosmosis in chloroplasts is primarily driven by the proton gradient across the thylakoid membrane. The movement of protons from the intermembrane space to the stroma is a secondary process that contributes to a lesser extent.