How do I calibrate the black and white point of a scanned image?

[lansing]

When I scanned my images to the computer, they don't look like the actually thing, where all the shadows have been brighten. How do I calibrate it?

For example, in this image, the clothes should be a lot darker:
https://i.imgur.com/ai1cncsh.jpg

[Asmodian]

To actually calibrate it? Something like this: i1photo pro2 (https://www.xrite.com/categories/calibration-profiling/i1photo-pro-2)

If you simply want to tweak it I have had decent results with IrfanView (http://www.irfanview.com/). You can have a histogram window open while adjusting the image, though the histogram requires manual updating after a change. If you are OK with command line I have done batch correction of scanned images with ImageMagick (https://www.imagemagick.org/script/download.php). I found -sigmoidal-contrast (https://www.imagemagick.org/script/command-line-options.php#sigmoidal-contrast) very useful.

[lansing]

I want to know how do I tweak it so that the color of the image match the real thing, and what's the logic behind it.
The i1photo doesn't have many videos that talk about scanning.

[lansing]

From what I read here, a cheap way to calibrate the scanner is to get one of those target image where it has a color palette of all color, print it out and then scan it back to the computer, and then generate a LUT matching the scanned image to the original target image. And that LUT would be the calibrate profile of the scanner. Is this correct?

http://www.booksmartstudio.com/color_tutorial/scanners.html

[Asmodian]

The problem with that solution is that the printer is in the middle so the colors on the paper being scanned are not those displayed on the screen. You need to profile the printer first. :(

[Ghitulescu]

Everything must be profiled, not only the printer or the scanner.
Also the monitors for graphical design are not regular monitors one find in the next corner shop.

What would be interesting would be a plugin that takes the colour of a click as "would be white" and makes it true white. Something professional cameras have onboard for a quick setting of a white balance.

[lansing]

A new way I found is to buy one of these colorcheckers. It has reference patches for all colors as well as white balance. Just scan the colorchecker with the scanner and match it with software like 3dlut creator, which has color templates for the popular colorcheckers already. The resulting lut would be the color profile for that scanner.

colorchecker (https://www.amazon.com/X-Rite-ColorChecker-Passport-Photo-MSCCPP/dp/B002NU5UW8/ref=sr_1_1?ie=UTF8&qid=1526899894&sr=8-1&keywords=colorchecker)