Initial Color Density Setting?

W. Fisher

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I profiled some new matte paper on 3880. The i1Photo 3D display of the profile showed the black to be a bit weak for my taste.

Looking in the Epson Properties > Paper Configuration > Color Density it is possible to lay more ink down. I went from the default of 0% up to 25% which did make the black lower by 8 RGB numbers from when it was 0%. This was using the first profile made with the zero density setting.

Question is should one make a density check and setting BEFORE on makes a profile? Maybe just print some RGB=0 image square and adjust the density until the black cannot go any lower than RGB=0 if it even can? My black Dmax is only RGB=50 at a 25% color density now and is not that black on the matte paper. Should I maybe raise the color density up to 50% first and also maybe slow the paper feed speed down as well?

Fwiw, the paper surface is not that flat and smooth and maybe why the ink or the spectrometer cannot get a good black reading. It's more of a ripple than a smooth matte (Red River Palo Duro Etching 315). Hopefully, I am printing on the correct side too - at least isn't running all over the place as it does on some papers if wrong.

Tia.
 

Ink stained Fingers

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- It is quite typical that 'black' on a matte like paper is not as black on a glossy paper, and it is quite typical that 3rd party papers may require different ink density settings than they are given as a preset via the normal paper selection . It could very well be that the paper supplier additional information to the user about their papers like providing an ICC profile or indicating a change of the ink density setting.

But I'm a kind of confused about your other statements

My black Dmax is only RGB=50 at a 25% color density now and is not that black on the matte paper.
You do not specify or measure the Dmax at RGB=50

Maybe just print some RGB=0 image square and adjust the density until the black cannot go any lower than RGB=0 if it even can
There is no way at all to reach a black level below RGB=0 , you'll always have a value slightly above 0.

If you want to use the density adjustment option via the driver you should do the testing before you do the actual profiling , that black density is needed to print your patch sheet correctly to profile that paper. This step is part of a linearization process which you do when you run your printer via RIP software bypassing all pre-settings of the driver and paper selection.
 

W. Fisher

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Thanks. Think I may need to do some sort of ink load prior to profiling with the matte paper. Glossy always seemed to make a better initial profile than a thick matte paper which may be sucking up the ink so not as black overall. The OBA paper may have less of a coating layer without the brightner added so the ink is duller overall, but don't know.

The Dmax RGB=50 is what I measured on the darkest black I got out of the profiled black. I would expect something lower than 50, but with the ink density load I used, it didn't happen to go blacker, but it's more of a dark gray than a black like I expected on a glossy paper.

I have a RIP when I did the K7 piezo ink thing, but I don't want to go down that rabbit hole again. Never saw any improvement by using it. Seemed more of a ink salesman gimmick, imho.
 

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The Dmax RGB=50
How do you measure such value with R=G=B ?

I assume that your RGB=50 is meant as about 20% in the range from 0 to 256 ? A luminance of L=20 is not very dark - I agree with you - but that is pretty much driven by the paper and its coating, I have seen matte papers as well with such a weak black level. You are right with your attempt to get some more ink onto the paper via the ink density setting, and you need to do some tests to see if an increase of density really improves the dark level, I assume that this density setting via the driver is a global parameter applying to all colors alike, be aware that you may reach a point that an increase of the density may not improve the color saturation anymore or may even reduce it - there is a point of color saturation reversal. This ink density setting gives you some additional room already, but a RIP would let you to control the ink density by color separately and as a total for mixed colors.
Piezography is a pretty special subject, and that RIP is just usable for piezography printing; it's RIP software in the sense that it bypasses the regular driver. RIP software for larger format printers start at about 500€ and higher - EFI software may be one example - or software by Shiraz , and there are more competitors.
 

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You are correct that a Lab 20 is around the RGB-50 for al three RGB values. The Color Picker in the ColorMunki Photo software reads in RGB and Lab both on a spot, and the i1 PhotoPro 2 only reads in Lab but one can convert the Lab to RGB with an online converter like this one: https://www.calculatormix.com/conversions/color/lab-to-rgb/ or going the other way in RGB to Lab with this one: http://colormine.org/convert/rgb-to-lab.

I have a RIP but haven't used it since my piezography days. I may try a Color Density on a black patch printed to the maximum 50% and see how that goes. Wasted paper making profiles with too weak of an ink load. Need to watch out doing that on matte papers I guess. Never thought it would be that weak in black
.
 
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Ink stained Fingers

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The Lab color space is more popular when dealing with profiles and similar, it separates the color related values from the luminance. Yes, there are several converters available like here - scroll down and you can convert into any conceivable color space

http://colormine.org/color-converter

The dark point is always a matter of the ink and the paper combined, I have seen several matte papers with similar black levels like L=20 , you can improve it to a degree with a higher ink density, but you'll stay far away from dark black levels you can get on particular glossy papers - down to L=2 . As soon as you go with 3rd party papers you have to do some testing to get the best out of it and whether such paper meets your requirements at all.

Printfab would be an entry level RIP for desktop printers which gives you access to ink level settings, but I don't like that software at all for the layout, parameters and user interface.

https://www.printfab.com/en/
 

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My computer SSD crashed and I had to buy and new one and reinstall Windows 10. What a mess! All profiles were wiped on the re-install so back to square one again.

I am printing B&W since getting a monochrome camera. My initial setup was to make a profile for the Epson Premium Glossy Paper. I used the 21 step gray scale off the QTR website download section ( 21 step wedge ) and printed it via Qimage Ultimate. I then entered all the RGB values read from my ColorMunki into a spreadsheet to see how linear the values were to what the charts values are (They are in Lab values 1-100, but I read the thing in RGB since the ColorMunki shows that first over Lab values.). In Qimage I made a slight alteration to the mid-line area of the curve (Lifted it a bit by maybe 6 points in Qimage and saved it as a B&W preset in the program.) which made the two lines almost perfectly linear.

Only matter is the Black Lab 100 value which the inks showed not a nice Lab=100 black, but more of a RGB=20 value (Not fully Black) which I sort of expected.

I made a duplicate run of the chart on top of the first one which put down more ink atop the first one. The Black patch 100 dropped to RGB=9 so it was darker with the second application of ink.

I suspect the initial ink load when I made the first ColorMunki profile was too light at zero in the Epson printer ink load parameters. Maybe setting a +25% more ink in the preferences might help before making an actual profile?

Ink linearity spreadsheet.jpg


W.F.
 
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W. Fisher

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I suspect that the ink load needs to be done BEFORE one makes any profile.

I printed the 21 step wedge above at a 0% load, and then increased in increments of 10%. I made six, one below each other on same page, at 0%, +10%, +20%, +30%, +40%, and +50%.

RGB value readouts off the ColorMunki Photo of the last black patch, or 100 on the step chart was:
0% = 19
+10% = 16
+20% = 14
+30% = 12
+40% = 14
+50% = 18

I forget what the term is for reversal of the black values when too much black is called, but it seems like I should set the printer preferences to print at +30% more ink than OEM of 0%.

W.F.
 

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Made a profile on same Epson Ultra Premium Glossy paper. One is OEM ink load density of 0% (The solid color below.). Second one (In larger wireframe below) was at a +30% ink density load inn the printer settings.

30 percent ink load.jpg


Going higher than +30% reduced the wireframe a lot, especially the black area underneath. So +30% on mine it is. prior to making any profile. These were with the InkjetMall K3 Ultra pigment inks and their HDD Photo Black inks.

The additional +30% ink load also increased the color gamut volume over 60,000 more than the OEM set to zero density ink load.

Color Volume of OEM inkload and plus 30 percent load.jpg
 
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