If you’re interested in the whole topic, it’s probably a good idea to read each section in order. If you just want to do the calibration and have access to Rawdigger, Photoshop, and Excel, read this: Preparing for monitor-based UniWB and do this: A one-step UniWB procedure.
Image processing for in-camera histograms
Making the in-camera histogram closely represent the raw histogram
Preparing for monitor-based UniWB
[…] summarized most of what I’ve learned about in-camera histograms and ETTR here. I’ll be adding a few details in the next few days, but it’s nearly […]