Don't know how I missed this until now. Andy_K did you make a decision? I am also trying to pick a Bianchi powdercoat color... Celeste is probably my goal but still undecided. I've got many of those same pictures you've shared saved for comparison.

Just to confuse you more, mine was originally black (ISO 1990 Bianchi Giro Paint Advice). This is the black I found closest match after ordering swatches, called matte black (as was the 1990 Giro) but more of a satin. https://www.prismaticpowders.com/sho...55/matte-black

Some of those white Bianchis of the era with the same style decals as the black, also just look extra sharp to me, don't know why. But the SLX models didn't come in white I don't think.

I have those same celeste swatches sitting in the garage. I stare at them time to time to no avail! I still am leaning towards RAL-6027, should it come to celeste.

Edit: thought I would add some photos from an old Pros Closet listing, as they were taken in good photography lighting I think.