QTR ink separation image prints with marks in the high density areas with fixxons

Hi all,

I'm having some struggles getting started with ink profiles and QTR. I've been making digital negatives for a while, but this is my first time trying to set up a process in my own home with my own printers (and it’s all making me feel exceptionally dumb! ).

I've made an inkjet print (on an Epson P5370 using the Premium Luster 260 paper profile) of the ink separation image to begin making an ink profile for UV printing. When I print it at 100% ink density I get marking in the densest portions of the image (90-100%).

When I print the separation image at 70% ink limit everything is grand (but the whites aren’t quite white).

I believe what’s happened here is I’ve saturated the fixxons and the marking is the print head running through the puddle. But I’m unsure.

What if anything should I do about this? I think I can continue building a profile with the instructions I have but I’m not super confident.

Any guidance would be appreciated!

The bands are posterization. Given that the ink load seems to drop back towards 100, you've got a weird curve setting with which you've printed that chart. I think you need to go into the curve creation tool and double check the settings for that curve. In particular, I can see how you're getting this issue if you mistakenly set this field to something lower than 100:


However, the main thing is to just go through the steps outlined in the QTR user manual and follow them diligently; odds are you're straying from the path there somewhere.

koraks said:

The bands are posterization. Given that the ink load seems to drop back towards 100, you've got a weird curve setting with which you've printed that chart. I think you need to go into the curve creation tool and double check the settings for that curve. In particular, I can see how you're getting this issue if you mistakenly set this field to something lower than 100:
View attachment 410766

However, the main thing is to just go through the steps outlined in the QTR user manual and follow them diligently; odds are you're straying from the path there somewhere.

Click to expand...

Hmmm this is printed from calibration mode at 100% ink density. I don’t have an option to select a curve in this mode and QTR bundles the image so I haven’t don’t any preprocessing. I attached a screen shot (so sorry that this was taken from my phone) of the settings that I printed with.

Hmm, that's odd. And you don't see this drop in density if you set the ink density slider to 70?

Btw, as long as you observe sufficient blocking power at lower ink densities, it might be possible to just ignore this issue.

koraks said:

Hmm, that's odd. And you don't see this drop in density if you set the ink density slider to 70?

Click to expand...

Exactly! I attached an image of the separation chart printed at 70%. At 70% the highlights are not entirely white, but no streaks are observed.

koraks said:

Btw, as long as you observe sufficient blocking power at lower ink densities, it might be possible to just ignore this issue.

Click to expand...

I’m mostly confident I can, but also wanted to go find advice from folks who had been down this path before. It would suck to do a lot of work only to discover that I had been off at the start!

Looking at the 100% wedge it probably goes full white around 80-85%, importantly before the streaking and reversion of density.

I think this should mean that as I go forward dialing in ink densities I should be fine for at least new cyanotype. It leaves me a little concerned about some of the other processes.

Oh! And the reason I mentioned my printer and paper settings was because what I haven’t done is adjust printer settings like the platen gap. I wasn’t sure if this is puddling whether I could improve the behavior by adjusting the paper settings. But the number of concurrent rabbit holes I can go down are limited.

Thanks; that cyanotype looks OK to me; I'd just proceed on that basis. I suspect that the phenomenon you're running into is an odd software glitch that may even be specific to this particular printer model.

I wouldn't worry too much about most other processes for now since New Cyanotype is on the high end of the scale of density requirements. You generally end up with something like 2.2logD being ideal for this process, which is also just about what works nicely for salted paper. The only process that comes to mind where significantly more density may be required (under specific circumstances) is carbon transfer - but even then there may be ways to avoid having to go so high up in density.

PS: I don't think the cause is the kind of smearing that you proposed in #1; in my experience you really get to see smears and ink deposited elsewhere if that happens - often along the edge of the sheet where there's a tiny little bump and the head rides a little lower across it. The reduced density steps look very neat & tidy to me, which makes me think that they are really a glitch on the software side of things.

Follow up on this, I continued to have this issue, and continued to hunt and peck. This post on pieziography.com seems almost identical to my issue: https://forums.piezography.com/t/print-problem-on-last-centimeters-with-p800/2250/5

I have since then tried a bunch of different settings adjustments. Of the adjustments I've made (suction, platen gap, paper thickness) the /only/ setting that has resolved the issue is that I increased the top border (leading edge) to 35mm, even then I just try to keep my print away from the edge of the print.

This is a bit of a bummer as it's just wasteful of materials, however it does seem to have completely resolved the issue, so if anyone has any other things that might be useful to try let me know!

Oh, that's remarkable.
In terms of wasting materials - you could consider the old trick of taping the transparency sheet onto a longer sheet of paper so the trailing 35mm is not the actual OHP film. Maybe that helps?

Okay, I think I found it. However there is a wrinkle.


This seems to be /exactly/ the issue. "microbanding" within one inch of the leading and trailing edges of the paper where rollers change hands. With the wrinkle that I am not using a "small" printer but a rather nice large one

I've left a message on the QTR groups.io forum (but I've left a couple now and not a single one has been responded to ha!)

[edit: direct link to Roy Harrington's post on the QTR forum referencing microbanding as a result of the roller hand off and how it's either bundled or not bundled in the driver for various printers https://groups.io/g/QuadToneRIP/message/12496]

Last one I swear:

Christina Anderson on using QTR with her school’s P5370.

“The only other thing I noticed at first was printing a half inch of less dense along the first or last edge of the image, but making an image only 9 inches tall and not up to the edge of the OHP solved that.”

But I don't see much of a sign of microbanding in your pictures...if you take a powerful loupe to those test sheets, do you see that pattern?
Is it indeed the first inch that's printed that's affected in your case as well?

koraks said:

But I don't see much of a sign of microbanding in your pictures...if you take a powerful loupe to those test sheets, do you see that pattern?
Is it indeed the first inch that's printed that's affected in your case as well?

Click to expand...

The pattern is only visible within the first inch and a half (or last inch and a half) of a print made with QTR. Otherwise (either beyond that margin or with another print driver) there are no visible signs of any anomalies to me.

Oh! And that margin is larger with roll feed, with sheet feed I’d say it is probably closer to the half inch that Christina Anderson mentions.