Linearization check with a Color Munki-is it possible?

InkjetMall Customer Support Piezography Inks & Printing
1

Hi to all, I wish to check the linearization of my recently scrounged 3800 and 7880 printers.
I do not have access to an i-1 device but DO have a Color Munki photo.
Any thoughts on if this could be used, before I start printing test charts?
Any links to relevant articles/sites or just guidelines would be much appreciated.

2

It’s been a while since I’ve done this, but you can riff off of this demo at northlight.

http://www.northlight-images.co.uk/article_pages/bw_printing/bw_print_colormunki.html

Cheers,
Walker

3

I recently tried using the Colormunki for a Linearization Check using an EPSON R2400 printer with Ultra Premium Presentation Paper. I tried both Spot and Scanning and saw different results.

4

It would be really informative if you could somehow manage to get that scanned by an i1 as well, to get some sense of which is more accurate. I’ve compared patch mode vs strip mode for the i1 using Measure Tool (Win7) and there was no significant difference.

5

That offer has been made and ignored before.

6

I will ask around to see if I can borrow an i1. I’ve been mulling over the purchase for a long time but haven’t been able to justify it. As far as my results go, I was wondering if I’m able to get the Colormunki properly centered on each of the small patches with the EYE-1.tif print. I performed the spot checks several times and the results were fairly close. So it seems you would say the differences are significant?

7

My experience has been that if I do one and plot the results, and then the other and paste in the results over the top in the spreadsheet, any movement in the black line is barely perceptible, and only if I look very, very carefully as I do the second paste. It’s been a while since I tried this, life being too short. So compared to that experience, I’d call this significant.

The departure from linearity is not all that bad, and back in the days before Roy Harrington’s .quad file relinearisation droplet I’d have been happy to print with either. Certainly not bad enough to pay $99US for a custom curve. The spot measurement suggests the highlights will print a little dark compared to linear, and the scanning measurement suggests that the mid-tones will print a little light and the shadows ever so light compared to linear.

What I wouldn’t do without knowing which is more accurate, is to run either through the .quad file relinearisation droplet, since in at least one case any inaccurate measurement may make matters worse rather than better.

8

Yes, agreed. Can’t seem to get my hands on an i1, so I will continue working out why the discrepency between spot and scanning on the Colormunki.

9

I recreated the Eye1.tif file so the patches were larger for me to scan and spot check off of. In the previous measurements I used the Eye1.tif for spot measurements and then used the Northlight 21-step target for the scan. The paper was the same for both though. Assume the different targets contributed to some of the differences. Using the same target for both scan and spot made the results about the same. Albeit not hugging the pink line through out, looks like midtones will be an issue. But I think I can go ahead and run the Harrington’s relinearisation droplet now?

By the way, is it adviseable to take multiple measurements and average doing a linearization check?

Thanks

10

I don’t claim to be an expert, but it does seem like you’ve achieved consistency, so I’d assume so.

With the same caveat, I nearly always work with the 21x4 which QTR uses to average measurements of four sets of patches. It’s not just measurement error that you’re looking to average out, but also printer variation. I sometimes plot the variation between the four sets and while not huge, there’s more than you’d expect. Sometimes there’s one aberrant patch, caused by printer variation since re-measurement on its own doesn’t fix it. One amongst four doesn’t have that much overall impact, but it would if you only measured a single set.

11

Thanks Brian! I assume you are using the i1 ? Do you think it’s a worthwhile investment (over the Colormunki)? I plan on getting into digital negatives soon, I assume I will need to take density measurements, not sure if the i1 has that capability, but I shall investigate.

I am also using my R2400 for piezography. I am considering moving it over to my 9800, wondering if you have any thoughts about that.

Lastly, I read somewhere you have a version of the Linearization_check.xls that doesn’t have the “File error: data may have been lost.” message upon opening. Could you share that?

Thanks!

Mark

12

So I’m not the only person who receives that damn error message…

13

I have never used a Munki and I know next to nothing about digital negatives, so I can’t really comment about those aspects. The i1 is an impressive piece of kit, and it seems that it does most things very well. Unfortunately the price reflects that. You have to take a deep breath to buy one, but most people who do don’t seem to regret it. You have to view it as a long-term investment.

The big advantage of the i1 over the Munki, as I understand it, is that the i1 can measure smaller patches. So you can print profiling charts with more patches on the same amount of paper, or use less paper for the same amount of patches, or some combination. I would not be surprised if the i1 is more accurate, but I don’t know whether that’s actually the case.

I have written a blog article containing my thoughts on printer selection. I have only very limited experience with Pro printers and none using Piezo. That said, my general advice to people is to take (another) deep breath before moving to a printer with ink lines and dampers for Piezo. But if you already have a 9800, you already know most of that.

I’m not sure what you read, but I haven’t said that. I’ve never seen that error. As you can see, the spreadsheet is locked. You could create your own version. All you really need is the luminosity tab, and it is fairly easy to create your own spreadsheet that does that. The pink line plots your luminosity data as the QTR linearise program spits it out. The black line is just a straight line between the max and the min values, the maths for which is pretty simple.

The density tab is effectively plotting the same data - i.e. it’s converting the density data that you enter into luminosity in order to plot it, so it doesn’t really add anything. It’s just an alternative way of entering the measurement data. Piezo is linear in luminosity. If you were to plot the density version it is a curved line. So if you really have problems, create your own using just the luminosity data, or download a fresh copy of the IJM one.

My advice would be to edit your post to remove your email address to prevent it being harvested by spammers. PMs are a better way to communicate email addresses…

14

I’m getting the error as well on the linearization checker xls w/ OS X Excel v 2011.

I’ll work on fixing this shortly. Other than the error, everything still works.

Best
Walker

15

Zooskifilms, did you successfully relinearise with your colormunki?

Shouldn’t it be possible to use the 21x4 patch Brian suggests with the colormunki? (perhaps the patches have to be enlarged?)

Larry