Table 1.

Instrument and user-to-user reproducibility. PQ SPAD and LEF were measured by two different users (30 measurements each) with three different devices (#62, #157 and #242, n = 10 for each device) on the youngest fully expanded leaves of tobacco (Nicotiana tabacum) plants grown in a growth chamber at 100 µmol photons m⁻² s⁻¹ and a 18 h photoperiod. Each of the MultispeQ devices was calibrated for SPAD against a Minolta SPAD 502 Plus, using a printed colour card with different hues of green, black and different thicknesses, averaging multiple measurements. LEF was measured using the standard procedures described in the text after appropriate calibrations of the PAR measurements and LED output as described for the data in figure 2. The table presents the normalized residuals between the values for each experiment and the expected values obtained from a hyperbolic saturation curve obtained by nonlinear fitting of the aggregated results.

measurement	device #62	device #157	device #242	user #A	user #B
SPAD	23.1 (0.9)	22.0 (0.4)	22.6 (0.4)	22.3 (0.5)	22.7 (0.9)
LEF (normalized)	1.02 (0.04)	0.98 (0.04)	0.99 (0.01)	0.99 (0.02)	1.0 (0.05)