Since the action is sometimes very violent, especially when the bullion is treated in the granulated form (it is steadier when thin plates are operated upon), it is found expedient to add the acid in several portions.
Being able to hold the camera steadier can lead to better shots.
The rain was steadier and the day was darker as they moved from their arrival gate to find the connecting flight to Norfolk.
This will help keep your hand steadier, resulting in a better line that doesn't wobble unevenly.