J-PLUS photospectrum of the cataclysmic variable J0743+4106. The blue side of the spectrum is dominated by the WD emission, while the red side is dominated by the secondary star. The J0660 filter shows the prominent Hα emission of the disk. For comparison, the spectrum from SDSS DR12 is shown in gray (but multiplied by a factor 0.012 to match the bluest filters). This spectrum was clearly obtained during a high mass-accretion phase, while the J-PLUS photometry was obtained during a low mass-accretion phase.