For some of my recent printing and paper tests, I have been using my office scanner to scan and evaluate results. To achieve neutral scans, in my recent test of the PRO-1000’s black and white mode I have been using a grey card as reference for color temperature corrections. However, for future tests I would prefer to have a properly profiled scanner for most accurate results, ideally without having to invest into an expensive photo scanner or commercial scanning software. An inquiry in the German DSLR-Forum lead to some good hints, and was able to successfully create and apply an ICC profile for my scanner using an inexpensive profiling target and the open source CoCa/ArgyllCMS software. In this blog post I’d like to document the steps I took, hopefully helping others with their scanner profiling.

Note: while “profiling” and “calibration” are both terms often used for generating ICC profiles for an input or output device, “profiling” is actually correct. “Calibration” would entail changing the configuration of the device, for example setting a monitor to a certain luminance or color temperature is a “calibration”, while generating an ICC profile for that monitor is “profiling”.

There are three steps to profiling a scanner:

• Obtain a profiling target
• Generate an ICC profile
• Apply the ICC profile to scanned files

Below a description of each of these steps.

Obtain a Profiling Target

The profiling target is an standardized test sheet containing color patches for profiling, which is scanned and then processed by profiling software. A common standard supported by most profiling software is IT8.7, and an inexpensive source for IT8.7 targets is Wolf Faust (www.coloraid.de). For scanner profiling you’ll need his “RF” target, described as “IT 8.7/2 Reflective Scanner Target on FUJICOLOR Crystal Archive paper (incl. CD)”.

That RF target comes at 10 Euro plus 5 Euro delivery within the EU and I ordered my target by directly transferring the money via Paypal, as described on the website. It took about 10 days for Wolf Faust do confirm the order and then another 2-3 days for the target to arrive.

The IT8.7 target from Wolf Faust

Generate an ICC Profile

ArgyllCMS is an open source color management system, and while it is command-line based, with CoCa there is a graphical frontend available for the generation of ICC profiles for scanners and cameras. The CoCa installation package already includes Argyll, so you do not need to download and install it separately.

To start the profiling process, you’ll first need to scan the profiling target and if necessary crop the image. Make sure that any image correction or enhancement settings are disabled in your scanning software. Here some screenshots from the scanning software of my HP scanner, however this will of course look different depending on the software you use:

Next you will need to convert the scan to a TIFF file, JPEG will NOT work with CoCa/ArgyllCMS.

When starting CoCa you’ll be presented with a straight-forward user interface.

To generate an ICC profile, first select the target image (1), the reference file supplied with the target (3) and the target type (6). At least on my system CoCa sent invalid values for the whitepoint adjustment and dark areas emphasis (5) to Argyll when they were left on default, so I had to change the values first and then set them back to their default of 1,00. In section (7), fill data on your device, with the “Internal Profile Description” being the name displayed in Photoshop and other applications. And finally, you need to select the algorithm/profile type to be used. ArgyllCMS recommends “Shaper + matrix” for scanners, and quality “High” should be sufficient for most applications.

After completing all these settings, press “Create Profile” and save the profile. To install the profile, go to its location in Windows Explorer, right-click and select “Install Profile”.

Notes: The ArgyllCMS documentation describes the usage scenario for scanner profiling, with some background information that is also relevant when using the CoCa frontend. Most important is the recommendation to generate a shaper/matrix profile for scanners (algorithm = “Shaper + matrix” in CoCa), and only if that does not lead to satisfactory results try a LUT profile with XYZ as profile connection space (algorithm = “XYZ cLUT” in CoCa). Another interesting piece of information regarding the IT8.7 targets from Wolf Faust is that Argyll contains a dedicated target template for those (argyll\ref\it8Wolf.cht instead of argyll\ref\it8.cht). During my test the standard template worked fine. CoCa does not allow you to choose the template, so if you’d like to use the dedicated Wolf Faust template with CoCa you will need to rename the it8Wolf.cht to it8.cht.

Apply the ICC Profile to Scanned Files

Once the ICC profile is created, it needs to be applied to scanned files. Most office-type scanning software does not support ICC profiles, as is the case for my HP scanning software. However, the profile can be applied after the scan in image editing software.

To do that in Adobe Photoshop, open the image and use the “Edit”, “Assign Profile…” command to assigning the scanner profile. Using the assign command will make Photoshop use the color values already stored in the file but interpret them according to the scanner profile, without any conversion. To then continue working with the file it should be converted into a working color space such as ProPhoto RGB or sRGB, using the “Edit”, “Convert to Profile…” command.

Here an animated before/after comparison of a scanned sample image. The difference is not night and day, but you can see that the second image with the applied profile is a bit brighter and warmer, and in my eyes closer to the original than the unprofiled scan shown in the first image:

Original image from the scanning software …

… and now with the scanner ICC profile applied.

Note: Firefox on a wide gamut monitor will oversaturate the animated GIF above. To avoid that, enable full color management in Firefox, by setting the gfx.color_management.mode configuration parameter to “1”.

Final Words

All in all I am quite happy with the results. At the cost of only 15 Euro for the profiling target and the use of CoCa/ArgyllCMS I was able to noticeably improve my scanning results without breaking the bank. 

If you are willing to spend a bit more you could also take a look at the Professional Edition of VueScan, coming in at 99,95 Euro. VueScan is a third party scanning software supporting thousands of scanner models, and will both generate the ICC profile for you and then apply it directly during the scanning process. It also supports the IT8.7 profiling target from Wolf Faust.

As always, I’d be happy to hear your comments or answer any questions you might have, feel free to contact me.