Sean, HX-HZ Persian Sand 1925 is different to HJ Persian Sand 1900. 1925 is the ONLY HX colour, all the rest are carryover HJ colours. Not sure what the actual formula difference is but I pulled tags off a HJ example in the 80's and the colour looks different to the HX colour. It almost looks redish or sort of has a burnt copper look. It was an Acacia Ridge build so has 2x tags painted in original colour, you can see them on my website in the Sandman section. Car had been resprayed hence the bit of fur on the ADR tag and the RH edge of the BODY tag, may have even been done in 1925. But under the bonnet was all original 1900, you can see that the colour is going to be one of thosr chameleon colours like Sepia that change drastically depending on the light.