I have been placing the freshly colored parts back in the heat treat oven at 350F and allowed to set for 30min and then turned off. At this point I have not had issues. Seems to darken colors. At this point the majority of my experimentation has been achieving colors more in line to the pre 1913 LC Smith's as the later marlin era guns as well as earlier Syracuse appeared different as expected. Currently the majority of my project guns that warrant a restoration fall in the hunter arms era so that is the look I am shooting for. As Mike has mentioned it takes looking at 97%+ condition guns colors to compare as what many are shooting for are not nowhere near close to factory even though they are nice.