Thermo Scientific NanoDrop 1000 V3.7 User Manual page 41

Section 8- Protein A280
(default setting), after each new report, or accumulate plots until
prompted to clear. The 'Clear Now' setting will clear all current and
previous plots. When the overlay function is active, the software
module will auto scale the y-axis based on the sample with the
highest absorbance at 280nm. Note: When the overlay function is
active, the 'Blank' function does not clear the existing overlaid sample
spectra.
8-5