I'm working with people over the internet to scan and document collectible cards. We each have different scanners, so a challenge we're facing is accurately syncing the colors between them. We have each purchased an R1 color target from http://www.targets.coloraid.de/. I generated ICC profiles using the target scans and LPROF. Then I applied the color profiles to scans of identical cards using Photoshop and converted the document profiles to sRGB ICE61966-2.1. I used Photoshop's default color settings and I've tried all 4 rendering intents for conversion. Yet the colors do not match! How can I use the color profiles to sync the images?
I've zipped up the color target scans, the ICC profiles that I created, and the card scans for your reference (All images reduced to make a reasonably sized download). Zip is 2.7 MB: https://www.dropbox.com/s/5x3vs968odwp73r/SO-Color-Profiles.zip
It seems that the colors do match. But the histograms do not line up. So if I manually apply a curves adjustment to set the white and black points for each scanner, the documents look accurate. This confuses me, since the color targets have a white to black range on them. I'd expect a color profile would adjust the darkness and lightness of color in addition to the hue. Is there any way to resolve this?
So according to joojaa, color profiles don't fix black and white values in the images. So my question then is, what can I do to correct the values using Photoshop?