> the tech support person had the gall to tell me they have different ink for different regions because the climates are different. I nearly swallowed my teeth at the stupidity of such a claim.

Can you explain why it is a stupid claim?

High humidity is known to affect things such as ink drying time which can affect print quality, so it isn't immediately obvious to me that it would be stupid to have different ink formulations for different climates.

Edit: note that I'm not saying that HP was telling the truth. I just wanted to know how the very idea that of different inks for different climates is apparently stupid.

Yes, in most places the humidity varies a good amount. But there are regions where it tends to be high most of the time, and regions where it tends to be low most of the time. It doesn't seem inherently absurd that an ink company might have say low, high, and regular humidity ink formulations designed for areas that are persistently low, persistently high, or neither.

You might expect this to be pointless because humidity often swings a fair amount each day, but that the way humidity affects printing is by changing the moisture of the paper. A place where humidity swings from low to high and back on something like a daily cycle is likely to have much smaller swings in paper moisture content. The paper will remain closer to the some sort of weighted average of past humidity.