High-speed OH*	Luminosity 059	Schlieren + single-shot 355 LIF	Soot incandescence
Camera	Phantom + double intensifier	Phantom v7.1	Photron SA-X2	Phantom v7.1
Lens f, f/#	105 mm, f/4.5	50 mm, f/1.2	85 mm, f/2.8	50 mm, f/16 – check –
Filter center, fwhm	310nm, 10 nm	<600 nm	628 nm, 32 nm	<600 nm
Lighting	–	–	635 nm LED, 1 µs pulse, 355 nm YAG for LIF	–
Frame period [µs]	50	50	6.7	?
Exp. time [µs]	2	46	2	?
Movie: Play or right-click to download			Schlieren and single-shot 355 LIF;	–
Description	310 nm natural emission. Dominated by OH* chemiluminescence near the lift-off length, but includes some soot incandescence contribution downstream. Flame stabilizes and moves back to the injector after the end of injection. Blue border is 50% of OH chemiluminescence threshold. Movie obtained simultaneously (same injection) as the <600 nm luminosity (at right).	Combustion chemiluminescence and soot luminosity are visible from natural emission. Soot luminosity background is dynamically corrected. Flame stabilizes and moves back to the injector after the end of injection. Blue border is 50% of high-temperature chemiluminescence threshold.	The coincidence of formaldehyde (CH2O) planar laser-induced fluorescence (PLIF) imaging is compared to the “softening” of refractive index gradients in the schlieren imaging during the low-temperature ignition event.	–
References	–	SAE 2012-01-1239; Bardi, 2012;	Skeen, 2014;	SAE 2014-01-1252
Additional files	Time record of 310-nm lift-off from movie above Liftoff vs time (310 nm)	Time record of <600 nm luminosity lift-off from movie above Liftoff vs time (<600 nm)	–	–