ArgyllCMS 875-patch printer profile with i1Pro 2

[The Hat]

Here below a print with a test image: upper image with the 875-patch target profile and lower image with the low 480-patch target profile:

To me both of these prints look perfect and would be more than acceptable to all concerning artists, which ever amount of patches used it’s all down to proper scanning, great job..

to calculate these correction factors for all of the in between 2 exp 24 = 16 million - possible RGB (8 bit) colors.

Noted you correctly mentioned 8 bit and not 16 bit, as most others think is possible with their printers..

On occasions in the past, I have over printed the same image twice to get the desired effect, and now I’ve learned that the newer modern printers don’t allow this over printing method anymore.. Can’t print on a previously printed page..

 

[pkk]

Gentlemen, you have been MORE than helpful. Making these profiles with Argyll has a pretty steep learning curve and you are both helping me get to the next level.

Thanks again!!

 

[Ink stained Fingers]

Can’t print on a previously printed page..

It could be that a paper sensor would not recognize a pre-printed sheet anymore as a blank sheet; I never tried that.

8 bit vs. 16 bit - it's a matter of internal calculations - the profile correction value for every image pixel needs to be calculated from the profile tables, this value need to be applied to the color value of each image pixel, and there is another step modifing the color values - the up- or downscaling of an image to the selected print resolution which is defined by the print quality parameter for the user , that's already 3 multiplications after each other, and there are probably more internally -e.g. when you use plug-ins in Photoshop or another editor. And the software then - at the end of all this converts 16 bit values to 8-bit values for print. The default setting of profile tables is 16 bit today, it was quite different 20 or more years ago - the processing power of processors was much lower and it took some time until the data went to the printer. So 16 bit internal arithmetic makes sense and is pretty much standard since a long time for lots of software packages. But using it outside this software environment is not necessary in most cases, but there are always exceptions like new image formats - e.g. HEIC - or HDR files.

There are those 16 Million RGB (8 bit) colors, a significant part is not printable, that's where the rendering intent of a profile comes into the game. The profile provides the information which color ranges can be replicated with the printer - all those colors within the gamut, and what should be done with those colors outside the gamut . You could compress all color data of an image such that all colors fit within the gamut , this works but with a loss of color saturation, or you print all colors within the gamut as they are and compess all out of gamut colors to the closest color on the gamut boundary, that kills color separation in saturated areas. Such considerations are worked into the profile slightly more sophisticated , so some more math is going on there - this at the time of profile calculation/generation, and all that works more accurately with 16 bit than with 8 bit.

 

[cerberus]

Actually the black level is now normal to my eyes when compared to other matte papers. However: the purple/blue has the about the same blackness as your black point. Maybe you did print with the HP Premium Glossy paper setting on this matte paper, which omits the black ink when printing "black".

Hello everyone, I followed the due care in the creation of this profile, paper type (Glossy) and 441 patches (only for tests), and I am satisfied with the results of the final print, although the equipment uses only the 4 CMYK colors, I am aware of its limitations in the color gamut. Thanks to all the comments as they helped me a lot.
Another question, I'm having problems profiling for an EPSON sublimation printer (F6370), because the colors are too far from what was expected, I'm sending the profiles I created separately (HP and EPSON).
In the case of EPSON, I used different densities of ink in EPSON's own RIP software, EPSON EDGE PRINT, 41%, 60% and 80%, with D50 and D65 filters.
The measurements were made patch by patch on the final fabric, and the results were the same as the measurements made on strip by strip.
I suspect that the paper used has FWA Additive, and I'm trying to create a .sp file in Argyll's illumread function (https://argyllcms.com/doc/illumread.html), but I can't find out if i1pro2 works, or even evaluate the final file created.
Any idea what I might be getting wrong?

 

[Ink stained Fingers]

The target of 875 patches, I am using in manual, is created with 729 colour patches in mind: if you consider the RGB colour space as a 3D-model with the XYZ-axes, the colour samples are taken with 9 steps in each XYZ-axes: for 0% for no ink ("white") and 100% for maximum saturation of one of the colours in mind: Red, Green and Blue (RGB). This means that you will have 9x9x9=729 colour patches to encompass all the possibilities in the RGB-colour space when making steps of 10% for sampling the colour space,

I checked the 875-target.tif mentioned above, the file shows a total of 4398 unique colors and not just 875, there are additional colors as borders between the color patches. Could you please recreate the target sheet with all borders set to black, I like to see if and how the 9x9x9 3D matrix has been created, and all the other 3500 colors create a color cloud overlaying and hiding the 9x9x9 matrix in the display. You may use the .png file extension instead of the typical .tif file format even zipped, .png does a lossless compression down to 2oo kb, and with all borders black it'll even be smaller.

 

[pharmacist]

You can regenerate the target again:

printtarg -v -ii1 -n -a0.8 -T360 -P -pA4 875-target

this produces patch layout for i1Pro (-ii1) with a smaller (80%) of the normal patch size at 360 dpi with 16-bit TIFF format (-T360), without spacers (-n) on A4 paper size (-pA4) from the 875-target.ti1 data

The above command will squeeze al patches on a single A4 size file

The above command will be without spacers so only the pure colours for the patches.

The 875-patch files include the 875-patch.ti1 and 875-patch.ti2 files, so you can generate the tiff-file yourself with our own customized layout with or without spacers.

The problem is caused by the spacers, but this can be easily removed by regenerating the target again with the commands above. But I have don it for you (smaller version 100 dpi)