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Digital BW, The Print

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Re: [Digital BW] solarized print

Re: [Digital BW] solarized print

2014-02-05 by Paul Roark

Paul,

Be sure that all the nozzles are firing -- that is, do a nozzle check.

Assuming that is fine, print a Calibration Mode print on the Premier Art 205 with the slider at 100. Then print a 21-step test strip with the profile K-0-40. That is in the profiles Zip file. You can then compare the densities of the individual inks on the Calibration Mode print, at their ink limits, to the K-0-40 test strip. I'm assuming you're using the "Eb6-PA-205" profile for this paper. The K ink limit on that profile is 40.

If you don't have a spectro, scan the Calibration mode print and the 21-step K-0-40 test strip at the same time. As long as the scan is not clipped, you can use the eyedropper in Photoshop to compare the dilute inks to the 21-step K-0-40. This comparison gives you the "Density" values that QTR needs. If the profile is not accurate for you setup, change it and save it under a different name.
In any case, you'll probably want re-linearize the profile. Print a 21-step test strip with the profile (with the Linearization tab values cleared). Measure it with a spectro or using the QTR Step Wedge tool with a scanner, and put the Lab L values into the QTR boxes.

Good luck,

Paul
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On Wed, Feb 5, 2014 at 11:09 AM, <paulmwhiting@...> wrote:

Hope I'm not wearing out my welcome!

Finally got my carts to be recognized in my refurbed 1400. Am using Premier Art Smooth FineArt paper. Am presently using InkJet Mall carts because their auto-reset chips have been programmed to be resettable at the user's discretion.

Am getting rather pronounced solarization in my shadows. It's a color file that's been converted to B/W using channels in PS Elements 9.

Paul Roark has contributed his profiles to QTR - but the profile for this paper was Black Only so he sent me one that uses all six positions. I noted there were two curves, but Curve 3 was whited out. Anyway, I tried a print with just Curve 1 and then Curve 1 and 2, same result. So should I tweak those curves in some way to get rid of the solarization? I might need some tips on how to do that, however.

Or is there something awry in my B/W conversion?

Paul W.


Re: solarized print

2014-02-05 by Leslie Tihor

Paul,
Print head misalignment can produce a texture resembling solarization in shadow areas. Try head alignment in your printer menu.
Les

Re: [Digital BW] solarized print

2014-02-06 by <paulmwhiting@...>

Thanks, Paul... looks like l deleted my original post, but it was in your reply. I was going to reword it before anyone replied but I didn't act quickly enough.


At any rate, I did run a nozzle check, and got a perfect pattern. I'll get working on a new curve per your instructions and also the QTR manual.


What's interesting is that another photograph printed out just fine. It has some shadows too but they were not colorized.


Thanks for your help, as always.


Paul

Re: [Digital BW] solarized print

2014-02-06 by Paul Roark

Did I hear you say earlier that you used RGB files?

If so, you might want to go to a grayscale gray gamma 2.2 as a uniform format. QTR will use some standard RGB to GS conversion, but if something had altered your RGB layers in processing such that they were not equal, color "pollution" might impact the results. It's just one variable that is real easy to eliminate.

Paul
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On Thu, Feb 6, 2014 at 10:04 AM, <paulmwhiting@...> wrote:

Thanks, Paul... looks like l deleted my original post, but it was in your reply. I was going to reword it before anyone replied but I didn't act quickly enough.


At any rate, I did run a nozzle check, and got a perfect pattern. I'll get working on a new curve per your instructions and also the QTR manual.


What's interesting is that another photograph printed out just fine. It has some shadows too but they were not colorized.


Thanks for your help, as always.


Paul


Re: [Digital BW] solarized print

2014-02-06 by <paulmwhiting@...>

Thanks for the suggestion, Les. I tried that but it didn't help. Looks like I'll have to bite the bullet and create a new profile.


Paul

Re: [Digital BW] solarized print

2014-02-06 by <paulmwhiting@...>

I did say that the file where I'm having "colorization" issues was originally a color file, and I converted it to a b/w file making the channels 60, 40, 0. I think I'll make a new conversion, and try printing that.

Sorry, but I don't understand "go to a grayscale gray gamma 2.2 as a uniform format". Still learning, still learning!

Paul

Re: [Digital BW] solarized print

2014-10-20 by paulmwhiting@...

This is an old thread, I hope it's still viable.

For those who are new, I deleted my original post because I wanted to re-word it, but before I was able to post a new one, Paul jumped in with an answer. He's too efficient! But he quoted my OP and  you can see how this thread got started.

Anyway, the reason I didn't follow up on his suggestions was because somehow the solarization got cleared up. But now it's back, and I tried the suggestions in the second paragraph. Here's what I got:

percent      Calibration Mode      21 step file
0                   255                         255
5                   150                         144
10                 102                           98
15                  67                            67
20                  62                            69
25                  45                            44
30                  33                            37
35                  37                            35
40                  35                            35
45                  35                            32

After that, they both level off and stay in the mid to low 30's all the way to black.

Looks pretty good to my unpracticed eye. It was hard to get a definite reading in each patch, I tried to put the eye dropper in the middle of each one. But throughout each patch there was quite a spread.

If these figures are ok, here's a couple of other things I've noticed:

1) If I choose the BO driver, I get no solarization, but the the black is not really as punchy as with my old 3MK-1800 setup. I certainly do like the 1400 better than my clog-prone 1800.

2) This may be more significant: the prints that are solarized come from scans of b/w negatives, both 35mm and 6x6. Prints from b/w conversion from a digital color file are ok. Granted, I've not done a lot of printing from scanned b/w negs lately, perhaps not enough to be significant. But still, maybe I'm scanning my b/w negs incorrectly. I'm using an Epson 4490. I have Color Management turned off.

Thanks all,

Paul

Re: [Digital BW] solarized print

2014-10-22 by paulmwhiting@...

My apologies... I just discovered an error in my carrying out Paul's suggestions. Something gnawed at me to look at my K-0-40 printout of the 21 step file. I discovered my K-0-40 curve had its default ink limit set to 100. Somehow I must have altered that a lont time ago.

Now, when I compare the "densities" of that file with the Calibration there is a significant difference between the two. I'll just list the first several entries:

percent... Calibration Print.... 21-step file
0.................. 0........................0
5..................151.....................192
10.................97......................156
15..................73.....................127
20..................55.....................107
25..................44.......................92
30...................40.....................82
35...................36......................74
40....................34......................70

and so on. The Calibration print levels off after this, but the 21 step entries don't level off till about 75 or 80%.

Again, these are not true densities but they are eyedropper readings of the steps when the two are compared with the eyedropper in Photoshop.

Now what... all I can think of is relinearizing.

Paul

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