Prior to its reignition V4334 Sgr is thought to have been cooling towards a white dwarf with a temperature around 100,000 K and a luminosity around . The luminosity rapidly increased about a hundred-fold and then the temperature decreased to around 10,000 K. The star developed the appearance of an F class supergiant (F2 Ia). The apparent temperature continued to cool to below 6,000 K and the star was gradually obscured at optical wavelengths by the formation of carbon dust, similar to an R CrB star. Since then the temperature has increased to around 20,000 K.