Effects of surface reactivity and ambient pressure on ignition characteristics of cool flames have been investigated experimentally. Mixtures of fuel and oxidizer impinge on a heated wall, and the cool flame is ignited on the wall by increasing wall temperatures at a constant speed. Two typical hydrocarbon fuels, DME and n-heptane, are tested with different oxygen fractions to adjust the low-temperature reactivity. The wall is coated with a 200 nm-thick layer of specific materials. It allows one to solely control chemical boundary conditions without modifying thermal boundary conditions. Reactive surface materials such as Fe, Pt, and Ru are tested as wall materials. The cool flame ignition behavior on each surface is compared with that on the SiO₂ surface, which is considered relatively inert. To examine the pressure effect, the ambient pressure is varied in the range from the atmospheric pressure to 4 atm. The formation of HCHO molecules in the cool flame is measured by means of two laser diagnostics resolved with the wall temperature: the planar laser-induced fluorescence (PLIF) and tunable diode laser absorption spectroscopy (TDLAS). The measurement results show that both the surface reactivity and ambient pressure significantly impact the cool flame ignition process.