The 2018–2025 ZTF data show a small colour change in the eclipses of ZTF J070412.91−112403.2

We measured the colour change during the known 34.57-day eclipses of ZTF J070412.91−112403.2. We used public ZTF DR24 photometry from 2018 to 2025. A fixed rule gave 68 pairs of g and r measurements at most 57.6 minutes apart. The eclipse core is 1.257 mag fainter in r than the bright phase. The median g−r colour increases by 0.175 mag. A bootstrap of whole orbital cycles gives 95% sampling intervals of 1.157–1.380 mag and 0.040–0.268 mag. The colour change divided by the r change is 0.139, with an interval of 0.033–0.209. A correction from nearby quiet objects gives a colour change of 0.177 mag. Tests of phase windows, image limits, errors, and overlap fields retain a small colour change relative to the eclipse depth. A stricter 28.8-minute time limit leaves only five core pairs and gives a colour interval that includes zero. Thus the evidence for reddening depends on the sample choice. Two filters do not determine the dust properties or the system geometry. The package preserves raw responses, query records, source code, figures, derived tables, and offline reproduction instructions. This work adds a measured colour contrast; the star, period, eclipses, and extra variation were reported before.

ZTF · ZTF J070412.91-112403.2 · eclipses · stellar variability · photometry · colour change · dust occultation · reproducible astronomy