Interesting experiment: using a cheap colorimeter to create printer profiles

[Apotheker]

At printerknowledge I am experimenting with a rather cheap colorimeter (called CR30 purchased at Aliexpress) to create printer profiles. With help of a programmer, who made me a python script I could generate very good RGB printer profiles with help of ArgyllCMS. The first preliminary tests and results are exciting: with only 228 patches I could generate pretty good prints on a cheap Canon TS705 printer on cheap paper with cheap aftermarket ink cartridges. The reason is that I could compare the whole procedure from scanning to generating the profiles side by side using a i1Pro1 scanning the same target (smaller patch adopted to the i1Pro1 specifications) and the prints are even more neutral (B&W) compared to its comparison profile generated using the i1Pro1.

I am still doing some tests with the same setting using different papers (glossy vs matte), ink sets (dye vs pigment) and printers (Canon TS705, Epson ET-8550 and Pro-900) to have a full picture of this nifty and relatively cheap colorimeter. The first results are very promising. I will post the results later when I can compare the results of my tests at printerknowledge.com

This way it will be possible to create satisfactory printer profiles at a fraction of the costs compared to the i1Studio/Colormunki/Calibrite Studio, the Spyderprint 4/5 colorimeters or even the very expensive i1Pro2/Pro3.

Possibility to convert csv-file with only L*A*B* values into a ArgyllCMS ti3 file

Yesterday I received a cheap aliexpress colorimeter that measures patches on surfaces and it gets only LAB-values registered. Is there somebody here, who is capable to convert this csv file into a CGAT compatible value so it can be converted to a ti3 file. My idea is to use this cheap...

www.printerknowledge.com

 

[kwaller]

Hi This is very interesting, been looking at the various printer / screen calibration tools, software but been put off by the prices.

Will be interested to see your completed results.

Regards

Keith W

 

[Apotheker]

OK, I have posted my results on printerknowledge.com and it is indeed feasible to use a cheap colorimeter to create satisfactory printer profiles with a limited budget.

The CR30 seems to create more neutral greys compared to my i1Pro1 (maybe because of its age and using a tungsten lamp (yellowing ???) versus the modern CR30 using LED illumination).

The CR30 has cost me about €55 at aliexpress, which makes a great deal als a poor man's spectro for generating printer profiles.

 

[Apotheker]

This is the CR30 colorimeter measuring the patch color:





Here a comparison in iccview between the same target: one scanned with the CR30 and the other a vintage i1Pro1 (GretagMacbeth) for the same printer/ink/paper combination:





Both profiles are very similar in cubic color units, shape and size.

This device can be purchased for about €55 (lowest price I have found).

--
printers, profiling, refilling, pharmacist @printerknowledge.com

 

[Apotheker]

After having some struggles with the previous version of the 247 patch target that has extra grey steps over the previous 228 patch target (unable to generate a profile due to the randomized patch order), I regenerated the target again to be non-randomized. Because this process gives a continuous grey ramp, making it sometimes difficult to determine visually where the border is of the next grey patch, I had to introduce a tiny space bar between the patches, so it is now instantly clear where the next (grey) patch will start.

In the ColorQC2 program is is important to set in the measurement settings:

measurement setting: M0, D50 and 2 degrees angle (as the colprof will use these settings as well to generate the profile: ..... i -D50 and -o 1931_2.....)

enable registration of the spectral data from: 400-700 nm: you will need this in the conversion script of python (many thanks/credits to @x64 at printerknowledge.com for the programming work), that will use these spectral data to convert it into a final ArgyllCMS compatible .ti3 file that depending on settings in the profile_config.ini of the python script package.

export in Excel format .xlsx and open in Excel to convert into .csv (comma separated file). DO NOT export directly from inside the ColorQC2 program, because there is a bug causing the data not properly written into a proper .csv file.

The Python script is flexible provided that the printtarg command must include the -r argument in order NOT to randomize your patches (otherwise you will run into trouble like me myself) and make sure the patch size is physically about 14x14mm in size after printing. This means a A4 page (210x297 mm). I will try to generate targets too for a larger patch target for 2 sheets of paper.

Possibility to convert csv-file with only L*A*B* values into a ArgyllCMS ti3 file

yes indeed, likewise my i1Pro1 and i1Pro2 white tile also is bound with a seria number to the device and cannot be exchanged, because each tile/spectro combo is factory calibrated to match.

www.printerknowledge.com

 

[Apotheker]

After I have done several tests with a side by side visual comparison and gamut 3D projection using iccview.de of the generated twin profiles (one with a i1Pro1 and one with the CR30 colorimeter) I came to the conclusion the CR30 is a very capable device to produce satisfactory printer profiles. I have made a single sheet 266 patch target that is good enough to stand up with the Colormunki/i1Studio 50 + 2x50 patch method (BW neutralising method). You can have a look and download the profiles and the python files (thanks to x64 and micronica at printerknowledge.com) to link the scanned csv file to the base ti2 and generate the ti3 file using a simple graphical user interface.

The CR30 seems to produce profiles that are a bit more neutral in greys compared to the ones created with the i1Pro1 (standard M0, D50/2, 1931_2 viewing angle).

The best of all the CR30 is available for about €55/$60 (lowest spotted price):





The white tile fo the CR30 for calibrating the device before spot reading:





--
printers, profiling, refilling, pharmacist @printerknowledge.com

 

[Ruby Rod]

Just got my CM30 today. Went with the $79 Amazon one, as I wasn't about to fool with Aliexpress or similar. Charged it up and initially it seemed like a dud- no display. Then I paired it with the computer's bluetooth and got the display working. I have no interest in a phone app, but using the QR code, that got me to the website and the PC app, which works surprisingly well. Only in the app can you change to D50, as the unit always defaults to D65. At any rate, the L*a*b* results match my ancient eye-one very closely. Also picked up a bunch of pointers on the printerknowledge site- Possibility to convert csv-file with only L*A*B* values into a ArgyllCMS ti3 file | PrinterKnowledge - Laser, 3D, Inkjet Printer Help

Thanks for the heads up on this incredibly cheap and surprisingly good device!

 

[Ruby Rod]

BTW, the website for this thing isn't spelled out anywhere, but this is it:

https://m.colormeter.net/index.jsp

 

[Apotheker]

After some PS and fiddling with the patch sizes I could cramp up 300 patches on a single sheet of A4 with 32 grey steps included. I have used my i1Pro2 to scan the same patch set and the profiles are near identical and also the white point is near identical (see printerknowledge.com latest link and download the files to see iccview.de).

 

[Apotheker]

I have made a 270 patch target especially for the US Letter format (216x279 mm) for those interested. It has 21 grey steps included. To be printed in the borderless setting, NO expansion retain size, color management: OFF. This is to guarantee the patches are maximized on the available paper surface to be scanned manually with the CR30 colorimeter. It has way more patches than the so-called SpyderPrint 225-patch "High Quality Target".

Possibility to convert csv-file with only L*A*B* values into a ArgyllCMS ti3 file

OK, so for the moment only non-randomized patches will work. This is not a big deal, but when using several grey steps, because the hue increased with each following patch with a little but and sometimes without spacebars it is difficult to determine the end/beginning of the next patch...

www.printerknowledge.com

 

[Apotheker]

A member at printerknowledge.com told me the CR30 is actually a real spectrophotometer and not (cheap) colorimeter using filters like the cheap Spyderprint 4/5 device that uses filters to determine the RGB values. The reason is the CR30 does indeed measures at different wave lengths between 400-700 nm and as such is much more accurate than the SpyderPrint 4/5 and is almost on pair with the expensive i1Pro.

.--
printers, profiling, refilling, pharmacist @printerknowledge.com

 

[Ruby Rod]

Yes, and it seems pretty accurate, though I haven't done an exhaustive test. Here's a screen shot using their ColorQC utility to show you the graph when measuring an orange card. This was with a Bluetooth connection- super convenient.







--
Ruby
(If you can't see my posts it's because I often say things that get them deleted!)

 

[Ruby Rod]

Here's the same orange card read with my elderly eye-one UVcut using Patchtool. The CM30 gives Lab 50.82, 58.49 and 49.60 whereas the eye-one gives 51.36, 59.15 and 51.00. Note that the CM30 is M0 and the eye-one UVcut is M2. I don't know what differences are attributable to that and what are simply calibration differences. This is also just one point, so don't make any huge generalizations.



--
Ruby
(If you can't see my posts it's because I often say things that get them deleted!)

 

[Adam2]

A member at printerknowledge.com told me the CR30 is actually a real spectrophotometer and not (cheap) colorimeter using filters like the cheap Spyderprint 4/5 device that uses filters to determine the RGB values. The reason is the CR30 does indeed measures at different wave lengths between 400-700 nm and as such is much more accurate than the SpyderPrint 4/5 and is almost on pair with the expensive i1Pro.

.--
printers, profiling, refilling, pharmacist @printerknowledge.com

That would explain why you obtained some reasonable results with the device. The i1Pro v1 uses an incandescent bulb which requires calibration and degrades over time. The newer ones use higher quality LED's which provide more consistent output.

 

[Ruby Rod]

Certainly, the bulbs degrade over time, but my guess is that when the unit calibrates on its ceramic reference tile, each spectral channel gets calibrated. So long as the bulb puts out an acceptable amount of light, the unit should be good to go. LEDs should be more stable than bulbs, but they also change a bit with age and temperature.

 

[E Dinkla]

I have made a 270 patch target especially for the US Letter format (216x279 mm) for those interested. It has 21 grey steps included. To be printed in the borderless setting, NO expansion retain size, color management: OFF. This is to guarantee the patches are maximized on the available paper surface to be scanned manually with the CR30 colorimeter. It has way more patches than the so-called SpyderPrint 225-patch "High Quality Target".

https://www.printerknowledge.com/th...s-into-a-argyllcms-ti3-file.17070/page-14#138

Nice to see that you found alternative hardware and created a path to use it. I was not sure whether it was really usable when I wrote about that possibility two months ago.

https://www.dpreview.com/forums/post/68414844

 

[E Dinkla]

Here's the same orange card read with my elderly eye-one UVcut using Patchtool. The CM30 gives Lab 50.82, 58.49 and 49.60 whereas the eye-one gives 51.36, 59.15 and 51.00. Note that the CM30 is M0 and the eye-one UVcut is M2. I don't know what differences are attributable to that and what are simply calibration differences. This is also just one point, so don't make any huge generalizations.

My i1Pro measures into UV but with its tungsten light not very deep into UV. I bought that version more than a decade ago for SpectrumViz to get info about the brighteners in inkjet papers. It delivers M0 readings but based on tungsten light. The ColorMunki Photo uses a LED light source but is UVcut so gives M2 readings. A similar UVcut spectrometer from X-rite is used in my HP Z3200-PS printer.

It will be interesting how far into UV the CM30 measures.

Met vriendelijke groet, Ernst
No photographer's gear list is complete without the printer mentioned !

 

[Ruby Rod]

It seems like almost every used i1 is a UVcut model. Mine is ancient, but seems to work well. I did some more tests that are on the Printerknowledge forum, showing the difference between papers with more and less OBAs. With the UVcut, the difference isn't nearly as much as with the CR30, pretty much as you'd expect. Reading the Red River papers on OBAs, I didn't know that they lose effectiveness over time, especially if not stored in the dark.

I have a few reflectance standards- https://www.labsphere.com/product/spectralon-diffuse-reflectance-standards/ and the CR30 shows very good flat response, with a slight roll off at the short wavelength end.

 

[Apotheker]

The CR30 reaches from 400 (outer limit of UV) to 700 nm wave length. The i1Pro2 from 380-730 nm, so very similar in range.

 

[E Dinkla]

The CR30 reaches from 400 (outer limit of UV) to 700 nm wave length. The i1Pro2 from 380-730 nm, so very similar in range.

The CR30 is then comparable to the HP Z3200 printer's integrated spectrometer which is a good instrument for printer profiling in my experience, both with the original HP profiling software (three versions over time) and ArgyllCMS. With the knowledge that OBA papers exposed to light sources containing UV, and no UV-cut filtering done one way or another, will throw them off balance. The ColorMunki Photo is similar. Spectral bandwidths vary in the specs sheets of the instruments though. EDit: my Z3200 measurement files show 10nm steps where the spec says 20nm. ArgyllCMS even allows another setting with finer steps for the manual X-rite instruments. Wonder whether that could be done for the CR30 too.





For my SpectrumViz measurements purpose the first i1Pro without UV filter was just better. It is not too often used for other tasks and I have also some primary colored acrylic tiles to control whether it shifted over time.



Met vriendelijke groet, Ernst
No photographer's gear list is complete without the printer mentioned !