A lighting panel includes a first circuit including a first LED configured to emit light at a first wavelength, a second circuit including a second LED configured to emit light at a second wavelength, and an adjustment circuit connected in parallel with the first circuit and configured to adjust a current through the first circuit. The adjustment circuit may include a trimmable resistor connected in parallel with the first circuit. Methods of manufacturing a lighting panel include mounting a plurality of lamps on a frame, each lamp including a first LED configured to emit light at a first wavelength and a second LED configured to emit light at a second wavelength, connecting selected ones of the first LEDs in a first circuit and selected ones of the second LEDs in a second circuit. An adjustment circuit, which may include a trimmable resistor, is connected in parallel with the first circuit, and a resistance of the adjustment circuit is adjusted to adjust a chromaticity of light emitted by the plurality of lamps when the plurality of lamps are energized.