I work part-time. So I'm a bit perplexed on how to properly map in a GANTT chart a task that has a smaller duration that the scheduled days, for instance I have to develop a tool in 3 weeks, but the real time I will spend on it is 8 days.
I was thinking of putting the schedule in light green and the real days of work in dark green. If I don't do it, that can make really huge bars, that aren't really representative of the importance of the task...
I encounter the same problem when I have a task that is scheduled for more time than it would be in reality, for instance when the person doing it has other responsibilities in parallel.
How is that done in a Gantt chart ?
On a Gantt chart you can stack several time spans on top of each other. This means that several things can be done at the same time. If we apply this to your first example, you could mark the allocated time in dark green and append tasks that you do during this time. If you want to indicate when you have finished, just attach a point in time called 'task completed' or something like that. And maybe you can also show the time used, just below the assigned time.