Diagram showing the intrinsic color parameter c, after subtracting the extrinsic color component E(B − V), as a function of redshift for our subluminous sample and the full ZTF DR2 sample. This isolates intrinsic color effects, revealing that our subluminous SNe Ia tend to be redder, with higher values, compared to normal SNe Ia. We note that the number of SNe included is reduced for both normal and subluminous subtypes, as this analysis requires reliable fits from both SALT2 and SNooPy.