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Example of color calibration and device profiling resources

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PrimeGoat:

Hi everyone,

I mentioned color management in previous posts.  Color management involves ICC profiles.  There is actually another way to do color-correct scans without needing ICC profiles.  This involves color calibration using color targets in the scans themselves.  The trickiest part of doing this is finding the right software for it.  I'm currently working on coding my own once I figure out the formula for transforming pixels based on 2 sets of color charts (source and target).  In the example, I'm using RoboRealm, which is currently a $2500 piece of software that I paid about $40 for years ago, which allows me to use their old version that I bought.  I'll show you some screenshots here to demonstrate what color calibration can do.

The chart being used here is the MacBeth ColorChecker standard, which uses 24 color patches.  These are typically used for calibrating cameras, but they work for scans as well.  There is also a more advanced kind called IT8, which uses many more patches, and is typically used for profiling printers.  It too can be used for staight calibration of an image.

The way that it works is all the color patches are defined in a reference.  When scanned, their apparent color is corrected for what color the reference says it should be, and all other colors in the image are corrected based on the difference profile between apparent and correct colorsets.

Original image:



Calibration in RoboRealm:


Calibrated image:


As you can see, the colors of the chart in the image were changed to match the colors in the color samples list, and the rest of the colors in the image followed suit.  The result is the color-correct version of the photo.  What was originally mis-colored blue, ended up as the properly colored tan carpet.  This method takes care of one third of the work - the scan.  The other two thirds are the editing and printing.  The printing would have to be with a profiled/calibrated printer.

If you want to get an ICC profile for your printer so that your printer will print colors exactly the way they're supposed to look as per PANTONE and sRGB colorspace standards, I recommend using one of the profiling services below.  All you need is to mail them a printout of a color chart that they provide (follow the instructions), pay them, and they will email you an .ICC profile for your printer.  Using this ICC profile will make all your prints have accurate colors.


* $25 - http://profilesbyrick.com/ - This is the one that I've used personally, and I've always had good results.
* $40 - https://www.greatprinterprofiles.com/how-to-order
* $99 - http://www.rpimaging.com/services/custom-icc-profiling.html
* $50 - https://www.drycreekphoto.com/custom/customprofiles.htm
* $50 - http://www.wattsdigital.com/customprinterprofiles.html
* $99 - http://www.chromix.com/colorvalet/pro/FAQ.cxsa
* ~$11 - https://www.permajet.com/Products/PermaJet-Custom-ICC-Profile-Services
* $25 - https://www.itsupplies.com/ProductDetails.asp?ProductCode=PROFILES
When printing out color charts, be sure to disable all color management and color correction in the printer and Photoshop settings.  You want it as RAW as possible.  The profile you'll be receiving will take care of all the color correction, so you don't need anything enabled.

If you want to get an IT8 target for profiling your scanner, go here: http://targets.coloraid.de/
IT8 target looks like this:

You can also use a scanner profiling service.  They'll require that you buy color targets that they specify, then they'll guide you through scanning them, you'll send them the scanned image, and they'll provide you with the .ICC profile.  I'm not sure of the pricing.  Visit them here: https://www.colourmanagement.net/services/camera-profiling-and-scanner-profiling

So, what is the result of having your scanner and printer both color-managed?  It means you can scan something and then print the image out, and the printed result will have colors that are identical to what you originally scanned.  If you're familiar with the process of copying, you'll know that colors are always slightly off.  This fixes the problem.  It's actually quite amazing when done right.  How does this help you with covers?  This allows your scans to be color-correct, so when you touch them up and print them out, they will look just like they're supposed to, just like the original.  This is of course a very good thing!

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