What is the difference between manual and automatic film processing?

This is a very interesting question. 

Manual Processing:

You manually move the film from one tank containing a specific chemical solution (developer, stop bath, fixer) to another, following a strict time and temperature regime. It takes significantly longer time, typically around 60 minutes per roll of film. Manual processing offers finer control over the development process, potentially leading to more customized results. It demands a good understanding of the chemicals and the processing steps to avoid errors. It is very much feasible as it requires minimal equipment - developing tanks, chemicals, and a thermometer. Manual processing is ideal for those who want more control and enjoy the hands-on experience.

Automatic Processing:

Here, films are loaded onto a feeder and the machine takes care of transporting them through various chemical baths, maintaining temperature and timing. It enables processing films much quicker, often around 8 minutes per roll. Automatic processing reduces variability in processing due to precise control of temperature and timing and less hands-on work, but some supervision is needed. It requires a dedicated machine and ongoing maintenance. Automatic processing is preferred for high volume, consistent results, and faster turnaround times, but comes at a higher cost.