Canon MF6180dw Manual page 517

<Data Size Priority>
<Normal>
<Image Quality
Priority>
7
Press [ ] (Menu) to close the menu screen.
Only a small amount of memory is required, but low-quality scans are produced.
The amount of memory required and resultant scan quality are somewhere in the middle
between <Data Size Priority> and <Image Quality Priority>.
A large amount of memory is required, but high-quality scans are produced.