How to generate a simple RGB printer profile using ArgyllCMS and the CR30 colorimeter/spectrophotometer

[pharmacist]

Having some time now I write simple manual how to generate a simple RGB printer profile using ArgyllCMS and the very affordable CR30 colorimeter that has been proven to be very reliable and accurate by multiple users on this forum and as well by some at dpreview.com.

As the necessary program only will work under Windows, MacOS users need to virtualize Windows and run the program with direct access to a virtual COM port assigned to the CR30.

First obtain the CR30 colorimeter. I have bought mine here:

https://nl.aliexpress.com/item/1005..._main.153.37c71802Oj4RR0&gatewayAdapt=glo2nld

Available with reduction during 11.11 promotion period

The next thing download and install Argyllcms:

https://argyllcms.com/

add the necessary path settings to your Windows environment settings and/or config.sys in order to access the argyllcms commands from any place on your computer.

The next thing is to install the ColorQC2 program, which connects the CR30 and forces the device to sample in the standard industry settings (M0, D50, 1931_2) measuring mode. The standalone reading without the ColorQC2 will use the D65 and 10 degrees angle measuring mode, which you do not want to use when generating a RGB printer profile. The exact link of the ColorQC program is a bit cryptic to me, but the device has tiny paper included with the exact link where to download this program.

Start the ColorQC2 program and go to connecting devices (you already have connect the CR30 with a USB-C cable to your computer):

Mine is connected to COM 3, but it might differ from your configuration:

If succesful your CR30 will give a beep and then choose in the menu: measurement settings in order to setup the necessary parameters that needs to be registered in the csv-file, which is feeded towards a script that will convert it to a working ArgyllCMS ti3 file needed to create the printer profile:

The next setting is important, as we are going to measure in the D50 mode and at 2 degrees angle (the industry standard D50/1932_2):

Now we are going to specify the exact data needed for the csv-file in order to generate the ti3 from from the measured data from the CR30: we will need to include the spectral data from 400 to 700 nm in 10 nm steps, so be sure all the spectral data will be registered in the csv-file. This is what you want. NOTE: to include the spectral data you will need scroll down from the first column until you see the spectral data option to be seen on the second column: choose from 400 to 700 nm to the last column and click save and close:

Above you see we will register test mode / light source+angle / L*A*B* value / spectral data from 400 to 700 nm in 10 nm steps

Press on the icon: test target and the ColorQC2 app will ask you to calibrate the black tile (which is hold the device about 1 meter from the ground):

After it is sucessful you will have to cap the spectro with the magnetic white tile to calibrate for the white calibration point:

Now we start measuring: place the device on the first patch of the printer target and press on the button on top of the CR30 spectro: it will register the color value in LAB values and also the spectral data (which is plotted below in the graph):

Continu the reading until you have read all the patches of the target. A 300 patch target can be read in just about 10 minutes with some excercise:

If you are ready will export the data as excel data and then from Excel or similar into a csv (comma separated) file. For some unknown reason direct export into a csv-file gives me a gibberish-like file which cannot be converted properly into a valid ArgyllCMS ti3 file. Not sure why this is case in my particular settings as others don't have this problem.

After you have saved the data in a Excel compatible xlsx file we will open the file in Excel and we have a look how many rows the data has. This is an extra control if you have done the reading correctly. A 300 patch target will have 301 rows (301 minus the upper one that describes the row corresponding column names below like LAB, measurement condition and angle, spectral data etc). If you have less or more than 301 rows than you have registered incorrectly and you will need to redo the scanning again:

Now we are going to export the xlsx file into a comma separated file which will be fed to the dispensary in order to create the ti3 file and ultimately the final printer profile:

In the next post I will use this csv-file with all the necessary data needed to create the final ti3 file with help of the CR30 conversion tool and convert it to the final printer target.

Edit: here are the files needed for the profile making process (below for download in zip-file)
and the cr30 dispensary github:

https://github.com/beerjongen/CR30-ti3-Dispensary

 

[ThrillaMozilla]

If you are ready will export the data as excel data and then from Excel or similar into a csv (comma separated) file. For some unknown reason direct export into a csv-file gives me a gibberish-like file which cannot be converted properly into a valid ArgyllCMS ti3 file. Not sure why this is case in my particular settings as others don't have this problem.

The CSV format is not standardized, and import of a CSV file can be quite problematic.

Thanks so much for your work on this. I believe the pertinent question is whether the device is any good, and more importantly, whether the profiles are good.

 

[pharmacist]

To answer your questions: yes the device is very good as well as the generated profiles. It has been crossed checked by another member at dpreview comparing it with his i1Pro1 device. I have the i1Pro1 and i1Pro2 to compare the generated profiles using the same patch set (ArgyllCMS) and it does produce very similar profiles in terms of size, volume and ultimately result in printing.

 

[ThrillaMozilla]

Amazing! Do you know how it compares to the i1Studio with x-rite software?

 

[pharmacist]

Well actually my first impression is that the 300 patch ArgyllCMS/CR30-target (a single sheet of A4) is comparable to the X-Rite i1Studio 50 + 2x50 BW neutralising method (the version you are using the second patch series grey/near neutral steps to neutralise BW printing in color images). I am really surprised by the accuracy of this CR30 spectro. NOTE: you have to choose the greenish version (CR30 and NOT the white CR10 or the bluish CR20: both of them are much less accurate according to the specs).

 

[pharmacist]

To pick up the first post I will now show you how to use the CR30 dispensary.

Thanks to @crenedecotret efforts to make a special randomizing ti1/pxf-file generator I managed to make a new 300 patch target for the CR30 which is finally randomized (in order to get a sharp in color/hue between adjacent patches).

Here is the link from @crenedecotret (pkpatches.zip) where you can add randomization of the grey patches into the ti1 file while remaining patch order in the ti2 file, which seems to be necessary for the CR30 dispensary python script to successfully generate the final printer profile.

https://www.printerknowledge.com/th...and-convert-to-i1profiler-patch-set.17122/#10

(post 10: pkpatches.zip to be used with python)

Install python (for Windows or Mac) first and use this github file set:

https://github.com/beerjongen/CR30-ti3-Dispensary (many thanks to @x64)

Start the gui.py file to load the app:

Load the csv-file that has been generated from your measurement with the ColorQC2 program (after you have first saved into a Excel compatible xlsx file and saved into a csv-file) into the app and also the corresponding ti2 file that belongs the target has been printed on the desired photo paper (for which you want a printer profile), properly dried and scanned with the CR30 spectro.

For most of us you can leave the rest of the settings on default settings.

Let the app generate your profile and after it is done you can install the profile by right clicking on your generated profile and choose: install profile in order to be available for all programs supporting color management.

 

[pharmacist]

@x64, @micronica, @crenedecotret : please add extra information to this topic in order to improve this rudimentary how-to manual if I have forgotten something or made a mistake.

 

[Epatcola]

Here is the link from @crenedecotret (pkpatches.zip) where you can add randomization of the grey patches into the ti1 file while remaining patch order in the ti2 file, which seems to be necessary for the CR30 dispensary python script to successfully generate the final printer profile.

Or you could just not use -r in printtarg to generate a fully randomised target and my awk script to generate the ti3 file. The script also takes csv files straight out of colorQC 2 with (an untested) version for csv files with semicolons and commas messed up by locales.

That said I don't buy all the greys sequentially in vertical columns are going to print differently when scattered randomly and you can't (currently anyway) scan targets with the CR30 so you don't need significant color changes between adjacent patches to help patch detection.

Readme from the .zip posted in the main CR30 thread attached.

 

[ThrillaMozilla]

This is very interesting. I noted the claim of more neutral grays.

I'm also a little concerned, though, by the risk of running Chinese software, with apparently no alternative. (?)

And is there an actual manual or concise source of essential info for this? I see things like "B2A detail" and "Total ink limit", and I have no idea what much of this stuff is.

 

[pharmacist]

just leave those settings on standard settings (B2A detail and total ink limit: the last one is for CMYK profiles only and you are going to generate a RGB printer profile).