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Author Topic: Any way to boost black ink?  (Read 6936 times)
Mack
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« on: September 09, 2013, 04:13:48 AM »

Did a little experiment.  I put a drop of ink of two ink carts out of the Epson 3880 onto some glossy paper, shook it off to the side a bit and blotted with a Q-tip the excess, let it dry for 30 minutes in the sun, and then measured the black matte and photo black of the two inks.

I got a reading of 2.254 for the Photo Black, and 2.337 for the Matte Black.  Really a nice black out of either, just the Matte was a little duller and not so glossy as the Photo Black.

However, the best black that I can get out of the printer is 1.724 with a profile made for that same paper and reading it as sRGB 0,0,0 in QU.  I read that "QuadTone RIP" has some "Black Ink Boost" but it only works for the 4900 I think and it is primarily a B&W print driver software for Epson only?  Surely there is a way to boost the black ink a bit more in Qimage without destroying or compressing the contrast for the darker dMax areas and bunching them all up?

I did see some Ink Color boost in the Epson driver (under Paper Config I think), but I don't know if that is the same thing and would need to be set each time.

Also been wondering if the Paper Thickness (or Platen/Printhead distance) would have any bearing on the black?  Head closer to the paper and maybe more ink into the pores and less spread out elsewhere?  Dunno.


Mack
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Ernst Dinkla
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« Reply #1 on: September 09, 2013, 08:27:17 PM »

On gloss paper with a 3880 and using PK you should get a Dmax above 2.0 and typically around 2.2, with whatever driver. My guess is that the media preset you use does not take the PK ink but stays with the MK. If that is a media preset for say bond paper it also lays down little ink.

What surprises me is that you get 2.3 with MK on a gloss paper, even with the dripped ink. Is that measured after the black surface gets a matte look so 24 or more hours later?

The high Dmax on gloss paper with a gloss black ink is that high because the resulting gloss black does reflect the light away from the spectro, colori or densitometer with the usual 45 degr angle illumination. A matte black still reflects light in more directions so the sensor gets some too.

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Met vriendelijke groet, Ernst

http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
July 2013, 500+ inkjet media white spectral plots.
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Mack
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« Reply #2 on: September 11, 2013, 02:38:19 AM »

On gloss paper with a 3880 and using PK you should get a Dmax above 2.0 and typically around 2.2, with whatever driver. My guess is that the media preset you use does not take the PK ink but stays with the MK. If that is a media preset for say bond paper it also lays down little ink.

What surprises me is that you get 2.3 with MK on a gloss paper, even with the dripped ink. Is that measured after the black surface gets a matte look so 24 or more hours later?

The high Dmax on gloss paper with a gloss black ink is that high because the resulting gloss black does reflect the light away from the spectro, colori or densitometer with the usual 45 degr angle illumination. A matte black still reflects light in more directions so the sensor gets some too.

--
Met vriendelijke groet, Ernst

http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
July 2013, 500+ inkjet media white spectral plots.

Ernst-

Yes.  I let the ink drops dry overnight outdoors and in the 100 degree daytime temps too.  Maybe 24 hours passed before I picked the paper up an read it in the i1.  Actually, the drops all appear to be a semi-gloss once dried but they are thicker than the inkjet would spray too.  The Matte Black may be more diffuse once sprayed.

I will note that I am using Jon Cone's "Dye" ink and not the Epson 3880 OEM "Pigment" K3 ink as I'm not fond of pigment on metallic papers and some super-gloss film that I sometimes do.  Might be his inks have a better dMax, but I dunno as I never dropped the ink out of the Epson OEM tanks to compare.  However, when I run it through the printer, the PK shows about 1.8 at dMax now.  Disappointing that is is quite a bit less than an ink drop test.  However, I did do some Matte black on a thick velour and it was black as charcoal, just I never measured it (yet).

I'm also playing around with the QuadTone RIP which is sort of bug-ridden (I/O 32 errors?) in Windows 8 with the GUI that is old.  So far using its old-tech GUI and dropping the image onto it and going straight to the printer, it produces a nice tonal range a nice black.  If I output the 21 step wedge they use to set it up with the same readings out of the i1 Photo Pro 2, and then pass it through their ICM script-maker executable, the ICM profile made is not as nice in the tonal range (blocks up the black end) and has some coloration added too.  It's odd that it bypasses the ICM profiles and Epson driver both on the "Drag-and-Drop" method, but using the ICM profiles generated with the Epson driver & QU it makes two very different images, no matter if I turn Color "On" or ABW (B&W) "On" in the Epson driver window either.  Best is the non-ICM one for me now and a more even tonal gradation too than the ICM made one.

I still have to play around with QuadTone RIP some more with B&W images.  Very different program and quirky setup.  I guess it makes sense if you work through it all.  I posted the odd curve image it made for the 3 gray inks out of the 3880 in the Technical Software part of this forum.  But they sure look nice on some of the "Northern Light B&W test images" where you can see well into the shadow details over the ones made using a ICM profile.

I probably should sign up for one of Jon Cone's ink classes where they even mix ink by hand for color control in B&W.  Then dump the 8 different shades of grey inks into some 3880 for fun and supposedly better tonal range and sharpness both.  The piezo ink printing guys doing all this black/grey ink stuff only are really excited over this stuff.


Mack
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Ernst Dinkla
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« Reply #3 on: September 11, 2013, 09:38:54 AM »



Ernst-

Yes.  I let the ink drops dry overnight outdoors and in the 100 degree daytime temps too.  Maybe 24 hours passed before I picked the paper up an read it in the i1.  Actually, the drops all appear to be a semi-gloss once dried but they are thicker than the inkjet would spray too.  The Matte Black may be more diffuse once sprayed.

I will note that I am using Jon Cone's "Dye" ink and not the Epson 3880 OEM "Pigment" K3 ink as I'm not fond of pigment on metallic papers and some super-gloss film that I sometimes do.  Might be his inks have a better dMax, but I dunno as I never dropped the ink out of the Epson OEM tanks to compare.  However, when I run it through the printer, the PK shows about 1.8 at dMax now.  Disappointing that is is quite a bit less than an ink drop test.  However, I did do some Matte black on a thick velour and it was black as charcoal, just I never measured it (yet).

Mack


Hello Mack,

Now that you added the right information, Cone dye inks, it becomes a bit more clear.
I assume you measured the density on a normal white gloss inkjet paper, not a metallic mirror type one? Which meter?

Black dye ink should give you a Dmax beyond 2.2 on white gloss papers and actually does a better job than pigment MK in Density on matte papers too. I can also understand now why your dripped "MK" ink on paper gets that high in Density, it is a dye ink, light drowns in thick black dye layers (or grey dye layers if thick enough) where it is reflected off the surface of pigment particles and off the pigment particles deeper within a pigment ink layer.

Did the Cone dye ink already replace the original inks in the 3880 ink tubes, both black channels ? Is the nozzle test pattern correct? Could it be that the PK black dye is not a black dye but a grey dye ink or not in the correct cartridge>ink channel of the 3880 ? I also think there is no reason to make a distinction between PK and MK black with dye inks, one of the advantages of dye ink but you need the two black ink cartridges + ink channels of the 3880 filled of course.

Do not think about QTR as a solution yet, the black dye should give you more than 2.2 D on gloss papers with any driver or RIP, there is something at the hardware/ink side that is not correct. If that is solved you can possibly add a 0.1 D with a black boost in QTR (for B&W prints only) if bleeding of the ink is not too high. I have worked with QTR and it does not have a color engine or ICC color management itself. Features of and problems with QTR are better discussed in the QuadTone list at Yahoo.


--
Met vriendelijke groet, Ernst

http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
July 2013, 500+ inkjet media white spectral plots.
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Mack
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« Reply #4 on: September 11, 2013, 03:59:08 PM »

Ernest-

Thanks for the feedback.  Yes, the Cone dye's have been in the 3880 for some time now.  In fact, I recently had to refill them all so they are getting a workout.  I don't think there is any residual OEM ink in the system lines now.  Printer nozzle checks are fine as I run those weekly on all my printers (I got a few.) and to keep clogs down on the unused ones.

What I may try is feeding a sheet of paper "twice" through it with a black B&W image via QU and see if the dMax builds beyond the 1.8 that I get now to the values of the ink drop.  I don't get why the "i1 Photo Pro 2" head that I use to read the density goes so high on the drops of ink.  I did find a bug in their software (Seems I'm good at that. Ask Mike.) where their ColorPort software only reads 255 for any RGB readings too.  It is stuck there in their software, but the L*ab side works correctly.  They are working on it - I hope.

I can set a black at sRGB 0 0 0 in PS and the inks are not hitting that value of the ink drop.  That's why I posed the question about a "Black Boost" in QU if the QuadTone RIP can do it (Haven't gotten that far yet.).  I don't believe the "Exposure" QU checkbox raises the dMax or does anything to that value in QU if the values are seen/set as sRGB 0 0 0 ?  I did see the ICM output the QuadTone RIP does (Some quid (sp?) file extension and some other one and not an ICM.) and they are simple text files that must apply density to each color ink.  I could see maybe a way there to kick the black up via those numbers as they build up in the table without mashing up the black tonality range much.

I think the Canon printer drivers allow one to raise each ink value independently of QU in the driver menu setup, but don't know if one turns Color to "Off" in QU if it affects that setting to some neutral value?  Epson only shows a Color Boost and not an independent for all the colors?  Someplace the "dye" may be laying down less ink out of the printer than the pigment ink is my theory right now even though I have re-written all the ICM profiles for dye.

Odd part is why I get such a dark black dMax with the dye via an "ink drop onto the paper" yet cannot out of the printer via an ICM?

Fwiw, this reminds me of the old Ansel Adams and Minor White tests of putting paper in sunlight and developing it to determine the paper's dMax (max. printing black) in the old chemistry baths, just messing with ink now.  Probably where I got the idea too.  Printing a sRGB 128 128 128 gray is hard enough, much as when our color darkroom instructor made us print a Kodak gray card with those damn CC filter packs.  Ugh!  In fact, I have a sRGB 128 128 128 file loaded on a card stuck into another printer and the readings off a test print out of it vary by maybe 6 points day to day and any of the colors both.  You can see the color differences day to day easily off it too.  Has to be ink or head issues, but it is OEM only and it changes all by itself.  I dunno.

Fwiw, a local auto color paint shop has all sorts of wiz-bang color analyzers and they still have to do a test spray-out and tweak the paint after they let them set for a day to match.  Boss showed me a white car and you could see maybe 5 shades of white, maybe different factories for some panels/bumpers/handles.  Never noticed it until he pointed it out.  Much like the same print to 5 different labs comes back differently I guess.

Oh well.  Guess no way to boost the black ink in QU that I can find, if it cannot be done somehow in the printer's driver menu.


Mack
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Ernst Dinkla
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« Reply #5 on: September 11, 2013, 07:42:47 PM »

It is simple, take QTR, a white gloss inkjet paper sheet (any good RC gloss inkjet paper will do), print the QTR partitioning target that lays down a 21 step tone range for every ink channel. See the manual how to do that. Switch the PK to MK black and do it again. Let the prints dry for 24 hours. Measure the 100% black and some steps below that. If that does not show a Dmax of more than 2.0 then something is wrong with your hardware/inks. That is as RAW as it gets from a printer. Printing the QTR linearisation target from Qimage Ultimate, driver setting at "Let application do color management", Qimage loaded with a Cone 3880 profile for that ink + gloss RC paper (I would expect Cone has that) should not give a much lighter black either. If it does then check you do not have an absurd Printer Filter in Qimage working at print time.

Dye ink prints are not stable just after printing and they are not stable a week later either. The main reason why proof printing on inkjets for offset presses etc is done with pigment inks these days. A HP Z3200 with OEM pigment inks like I have is consistent in output, the more when the schedule for calibration with its integrated spectrometer is kept.

Your messages tend to divert to all directions but first you have to fix this low Dmax.

My last message, complain at Cone's forum that something is wrong with the inks if this all does not give you a decent Dmax on gloss paper.

--
Met vriendelijke groet, Ernst

http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
July 2013, 500+ inkjet media white spectral plots.
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