The influence of the oxygen balance, A, of an anthracene-type aromatic fuel in flare compositions on the spectral color ratio, that is the ratio of radiation emitted in band A (X = 1.8-2.5 mu m) versus radiation emitted in band B (lambda = 3.5-4.8 mu m), is investigated. Eight compositions based on potassium Perchlorate, polychloroprene binder and either of the following fuels, anthracene, C14H10 (1), anthracene-d(10), C14D10 (2), phenanthrene C14H10 (3), anthrone, C14H10O (4), anthraquitione, C14H8O2 (5), 1-aminoanthraquinone, C14H9NO2 (6), 1,5-dihydroxyanthraquinone, C14H8O4 (7) and 1,5-dinitroanthraquinone, C14H6N2O6 (8) were prepared and radiometrically investigated. The highest spectral efficiency, E, in A-band is obtained with the phenanthrene based composition D3. This mixture also displays the lowest spectral color ratio, theta(A/B). The highest color ratio is obtained with 1,5-dihydroxyanthraquinone as fuel. The burn rate is highest with anthracene and decreases steadily with increasing oxygen balance of the fuel. The thermodynamic equilibrium compositions, combustion temperatures and spectral efficiencies are given. For part II see Ref. [3].