What key do you hold down to speed up a transformation value change by a factor of 10?

Holding down the Shift key while adjusting a transformation value in Adobe After Effects allows you to speed up that change by a factor of 10. This is particularly useful for making large adjustments quickly, as it enables you to fine-tune parameters like position, scale, rotation, and opacity more efficiently. When you are making such transformations, holding down the Shift key ensures that each increment you make is multiplied, allowing for swift and significant changes without the need for repetitive adjustments.

The other keys mentioned don’t provide this specific enhancement when altering transformation values. The Control key generally invokes different functionality depending on the operating system and context, while the Alt and Command keys serve unique purposes like creating duplicates and other shortcuts that do not relate to speeding up transformation value changes. Thus, using Shift is the correct practice in this scenario.