A lightning direct effects, LDE, testing system comprising: a test chamber; a test article disposed in the test chamber; at least one capacitor coupled, via a capacitor wire, to the test article, the at least one capacitor operable to inject a current, simulating a lightning strike, into the test article, to create a spark on the test article, the spark emitting a spark spectral signature, and the spark having a spark light intensity, and the test article coupled to a ground wire dissipating the current to a ground, characterised in that the lightning direct effects testing system further comprises a digitally-controlled reference light source disposed in the test chamber, the digitally-controlled reference light source operable to emit a reference light source spectral signature simulating an observed spark spectral signature of sparking in tested test articles, and the digitally-controlled reference light source having a reference light source light intensity equivalent to an observed spark light intensity of an observed spark having an energy equal to a minimum ignition energy threshold; a camera positioned at the test chamber, the camera having a camera lens facing the test article and the digitally-controlled reference light source, and having a field of view to detect the spark and the digitally-controlled reference light source, and the camera operable to capture an image that includes the spark spectral signature, the spark light intensity, the reference light source spectral signature, and the reference light source light intensity; a controller system having a controller operable to digitally control the digitally-controlled reference light source, the controller system having an input portion coupled to the ground wire, via a current sensor probe assembly, and the controller system having an output portion coupled to the digitally-controlled reference light source, via a fiber optic link; and a computer system coupled to the camera, operable to receive the image, and to determine a passing result or a failing result of a LDE testing criteria for the test article, by measuring and comparing the spark light intensity of the spark on the test article against the reference light source light intensity of the digitally-controlled reference light source. a test chamber; a test article disposed in the test chamber; at least one capacitor coupled, via a capacitor wire, to the test article, the at least one capacitor operable to inject a current, simulating a lightning strike, into the test article, to create a spark on the test article, the spark emitting a spark spectral signature, and the spark having a spark light intensity, and the test article coupled to a ground wire dissipating the current to a ground, characterised in that the lightning direct effects testing system further comprises a digitally-controlled reference light source disposed in the test chamber, the digitally-controlled reference light source operable to emit a reference light source spectral signature simulating an observed spark spectral signature of sparking in tested test articles, and the digitally-controlled reference light source having a reference light source light intensity equivalent to an observed spark light intensity of an observed spark having an energy equal to a minimum ignition energy threshold; a camera positioned at the test chamber, the camera having a camera lens facing the test article and the digitally-controlled reference light source, and having a field of view to detect the spark and the digitally-controlled reference light source, and the camera operable to capture an image that includes the spark spectral signature, the spark light intensity, the reference light source spectral signature, and the reference light source light intensity; a controller system having a controller operable to digitally control the digitally-controlled reference light source, the controller system having an input portion coupled to the ground wire, via a current sensor probe assembly, and the controller system having an output portion coupled to the digitally-controlled reference light source, via a fiber optic link; and a computer system coupled to the camera, operable to receive the image, and to determine a passing result or a failing result of a LDE testing criteria for the test article, by measuring and comparing the spark light intensity of the spark on the test article against the reference light source light intensity of the digitally-controlled reference light source.