How to measure densities to insure proper linearization of WNK7 inkset

qtr
curves
piezography

#1

Having successfully installed the WNK7 inkset and QTR, I have printed both the 21 and 51 step wedges along with an image. By visual measure only, it appears that the tonal scale is not achieving maximum density. It appears perfectly linear, however, the blacks are not as black as they should be. This also is corroborated in the image file, which has lots of dark shadow values (90-99%) that are not printing as dark as they should. THis 9800 printer previously had Epson color inks, and was also not printing with the proper density in the darkest values, something that I was concerned about when I purchased the printer recently. At the time Jon suggested a custom curve could be made to accomodate this printer issue once I switched to the K7 inkset, and I am almost ready to do that. However, if you could guide me about using the Eye-One to measure density, it would give me a better idea if I am barking up the right tree or not. I have previously used it in conjunction with the StudioPrint RIP to linearize, but am not sure what software to use to measure the step wedges that I downloaded from QTR. Where can I find info on this? Thank you!!!


#2

Just to add to the above, the image has an embedded gamma 2.2 profile, I used the proper QTR profile for the paper, and feel comfortable that all procedures for output were followed (no color mgt, 2880, unidirectional, etc.). Thanks!


#3

Answering my own questions, I have found “Piezography Custom Profiling Manual”, which seems to be exactly what I need next. I will read through and perform the linearization check, using the Measure Tool and my Eye-One. Will post results or any further questions. Hoping this is the correct path.


#4

If you have Photo Rag and can measure the L value or density value on the black patch and let us know what is - we can tell you if you are at dMax or if your head is not able to produce the type of micro dots required to make more density. You did mention 90-99%. Only 100% prints as a black. 99% is lighter visibly, and 98% is visibly lighter than 99%. You used to be on Studio Print and it can not differentiate between all 256 gray values as can our K7 curves. So you have stepped into a much higher fidelity system. If you find your black patch on the 21 step to measure at or near 1.64 dMax - then you can produce black and you will just need to move more of your intended black bits to actual black. Make sense?


#5

I understand you in theory! I am not sure what procedure to use to measure the density value of the black patch. I have an Eye-One, but have only used it to measure densities through the StudioPrint RIP, so not sure how to do it otherwise. I’ve read through the “Piezography Custon Profilling Manual” and see the steps to follow on “Linearization CHeck Printing Insturctions”, pgs 8/9- do I follow this whole procedure, including using the “Measure Tool” from the xrite.com site and Excel? Help is muchly appreciated!


#6

Looking on the xrite.com site under Support for any downloadable pkg named “Measure Tool” and coming up empty. I have an x-rite Eye-One purchased several years back. Can anyone direct me to the proper place?


#7

More questions… I found the Measure Tool 5 on the xrite.com site, however, it is unclear if I should download "FOGRA REference Files (39 and 40)- or the Profile Maker 5 which seems to be the compatible software for Snow Leopard (which I am on). I am very confused. Can you explain?


#8

Garie,

We maintain OS X 10.4.7 for using X-Rite and the Measure Tool. It may be the last supported Mac OS X which supported many different color management tools. Certainly it was the last OS X version that allowed “no color management”.

Profile Maker 5 requires an expensive dongle. You would not want to buy it just to make this measurement.

Send in the 21 step that you print using the correct K7 curve and we will measure for you and let you know if the system is working and whether if you want more black you need to make more black pixels (100%). In Piezography K7, 90% is very dark gray. 95% is even darker gray - not black! Only 100% is black. Purposely, 99% is most definitely not black. We are making 256 tonal separations that you can specify using Photoshop. We are printing tens of thousands of gray levels. Black is only L = 0 or density = 100%. L1 is lighter than black. 99% is lighter than black. Studio Print can NOT make that same tonal separation. So files that used to print black in the 90-99% range are very dark grays with K7 curves.


#9

Thanks so much Jon- I will print and send to you right away! As you’ve described, my files are adjusted for the StudioPrint output scenario although I was able to discern the differences between 100, 98 and 96%K, …but as you are saying, with QTR I will have to shift the tonalities downscale more than I was used to. At least I’m hoping that’s the issue. If my 21 step does not get a good dmax at 100% can you use what I am sending to make a custom curve? Thanks for all your help.


#10

I will keep my eye out for your print and let you know my findings as soon as I measure and plot your output linearization.
No, we need a printed 256 patch target to make a custom curve. You can find everything you need to have a custom curve made (instructions, master curve + printable target), here: http://shopping.netsuite.com/s.nl/c.362672/it.A/id.3682/.f?sc=15&category=-115#

All the best~ Dana :slight_smile:


#11

Hi Garie~

I just received your printed samples on Friday, and checked them today.

Based on the printed 21 step strip you provided, your output linearization is nearly perfect, and dMax is 1.61, which is normal for Photo Rag paper.

One thing that immediately jumped out at me is the yellow color staining in your highlights, caused by stubborn yellow color ink remaining in the line and/or damper. I recommend you do a few more power clean cycles or print pure sheets from the yellow channel to eliminate the color staining. Instructions for printing pure ink from an individual channel can be found here: http://www.inkjetmall.com/tech/content.php?144-Print-Ink-Separation-Image-thru-QTR-Calibration-Mode

Other than the yellow cast to your highlights, I feel your output is good/correct.

Please let me know if you have questions or there’s anything else we can help you with.
Best regards and happy printing~ Dana :slight_smile:


#12

Garie,

So, if there is too much shadow detail for you, simply compress the shadows with a curve to make more of the shadow detail black. K7 and K6 has a lot more tonal variations than you are used to with the StudioPrint RIP. It also has more breath in that it is producing tons more gray values than StudioPrint. You will get used to it and eventually not look back!

Jon


#13

Thank you both! Sorry I have been unable to work this week and just now saw your comments. It is reassuring that the linearization and DMax are good, and I guess I will get used to how different the files need to be with QTR and K7 from my previous StudioPrint/piezotone setup. I am now getting a sense of how challenging it must have been to translate my old files to your system at Cone Editions. Dana- I will follow your advice about the yellow staining. Will be in touch and thanks again for your help!


#14

You’re on the right track Garie!
Now it’s a matter if getting used to the output with Piezography K7 inks and QuadTone RIP after using PiezoTone and StudioPrint for so many years.
Keep in mind, when we print your work in our studio, we are using K7 inks, but still use StudioPrint to get as close to your previous output as possible. QuadTone RIP prints linear Gamma 2.2, for open shadows and highlights- so it will look slightly flat and take some getting used to at first, after printing with the more contrasty gamma 1.8 for so long. You have two choices for printing with your new 9800 Piezography K7 setup- learn QTR and get comfortable working with the linear output, or continue using StudioPrint and just get used to the ink (and printer) change. I suggest you try both to compare the output before deciding which you prefer, and you may find you like things about both, but I suspect you may go with QTR and some contrast adjustments in your files, due to the detail and smoothness QTR produces.

Keep us posted and let me know if there’s anything else I can help you with.
All the best~ Dana :slight_smile:


#15

Thank you! I was taken a bit by surprise at the contrast difference, and will follow up on doing a StudioPrint comparison as well. I am finding QTR very simple to use- it’s just the redistribution of tonalities that I will have to get used to. Thanks for your help. Enjoy what looks like a glorious fall! All the best- Garie


#16

Sounds good, keep us posted!
Best regards and happy printing~ Dana :slight_smile: