how do i calibrate the monitor on my new iMac24 for photography?

Thank you, Mal-S. This author prefers X-Rite over DataColor spider colorimeters, but admits he hasn’t tried the new SpiderX products. It looks like I would have to run it through Rosetta program, since I have an M1 chip if I buy the SpiderX. I don’t know whether that matters. Either way, I’m guessing I have to buy the hardware, not just download the software. I’m not sure how these products go about altering the colors on my iMac. Any insight would be appreciated. I don’t want to mess with my monitor and then regret it.

BTW, in the meantime, I lowered the brightness level on my screen down to a bit over one-third. It was set to about 2/3rds level from the factory. And I clicked the automatically adjust brightness button off. Both of these helped. My yellows now look more accurate. But my blues are off in color. Since I do a lot of landscape photography, blues are important for my skies. This was also a major problem on my last IMac. I’d like to resolve that problem with this new iMac.

Thanks again for any assistance. I’m trying to educate myself and reduce my waste in printing pix that are off in color and brightness.