Using GutenPrint with a custom B&W inkset

Maybe I'm not doing something right but I've never been a fan of QTR. It's output for me has always been subpar and error prone. I.e. unsharp results compared to the Epson driver, ink running off the paper when limits are too high etc. So recently I started looking at GutenPrint as a custom RIP for a custom B&W inkset. As far as I can tell no one has attempted this except possibly the GutenPrint developers...

I've managed to come to a working solution with GutenPrint after some experimentation. Advantages I see in GutenPrint:

* Density is easily controlled using Print driver settings - if you want a digital negative with more ink blocking you can up the density at the time of printing by changing "Output Controls Extra 1 -> Density" when printing.
* Better printer support- this procedure could be used by printers other than Epson since GutenPrint supports many more printers than QTR. The caveat being I'm not sure how many non-Epson printers have a defined Quadtone inkset type yet available for customization.
* GutenPrint has a 5760x2880 DPI printing mode for Epson printers which QTR seems to lack. Results are visibly sharper, with the disadvantage being very slow printing times (not a concern for me)
* Many many more options are customizable. QTR is based off an earlier version of GutenPrint (then known as GIMP Print). GutenPrint has evolved since so you have more fine grained control with more algorithms available for things like Dither method etc

Here's the basic procedure for using an Epson 1430 with a custom B&W inkset with GutenPrint on a Mac.

* Mix your ink as you would normally and fill up your refillable cartridges. Sandy King's recently released manual of Carbon Printing has detailed instructions on designing and creating a custom B&W inkset. I based mine off mixes of ConeColor Pro Photo black, Light black and Light light black ink available from Inkjet Mall. Since you only need 3 inks it's quite economical.
* Use QTR to print off a calibration chart and then use a scanner or densitometer to get the relative densities of your inks. I.e. Photo black should be 1.0 and has a density of say 2.0. If your next darkest ink has a density of 1.6 then it's relative density is 1.6/2.0 = 0.8
* Install GutenPrint, add a printer using the Mac Dialog box select the printer and "Select Software" to find your Gutenprint driver for your printer
* When printing go to "Printer Features" in the System print dialog.
* Adjust these settings:
* General -> Adjust resolution to 5760x2880 dpi unless you want faster printing times at the expense of quality
* Output Control Common -> Select Photograph for the media type
* Printer Features Common -> Change Inkset to MIS Six tone
* Output Controls Extra 5 -> Scroll down to the Hextone section. There should be a section for each Hextone value from 5 to 1. 5 being the next darkest ink after black. For each of the value's put in the relative density.

Make a test print. The test print should print reasonably well but will probably have transition problems. I don't quite yet grasp the Hextone transition values but experimentation has led me to put a Hextone transition value going from 0.1 for Hextone 5 to 0.5 for Hextone 1 to work well. Basically linearly adjusting the transition values for each lighter ink. More experimentation/research needed here.

Hope this helps. This post wasn't intended to be a dig at QuadTone RIP but as a starting point for those who want to experiment with different printing methods. If anything else it adds another tool to the toolbox for those using all-gray inksets.

Is it possible to control output from the individual shades of gray with GutenPrint, as in QTR?

Sandy

Sandy,

It appears you can. I mentioned in my first post, if you set the Hextone Density Values to be a relative density value of the blackest ink then the output is basically equivalent to "GRAY_VAL" in QTR. If you want to further control ink density values per shade you can apply a Hextone Density Scale (per channel) in Gutenprint, which seems to be basically a multiplier on ink density.

Note- one thing I forgot to mention in the original post- in order to establish a mapping between a Hextone "X" value and an actual Ink Channel you need to read the Gutenprint XML file that defines the MIS Six Tone ink set (in the case of the Epson 1430 anyways). Here's the claria.xml file that defines the MIS Six Tone and basically defines the mapping between the Hextone 1-5 values and an ink channel.

Each subchannel node has a color and subchannel attribute which maps back to a ink channel. See the Standard Six color Photo at the top of the file to figure out which channel is which. For example - color="0" subchannel="0" is Black. color="1" subchannel="1" is Light Magenta etc.

Again not saying anything of this is particularly easy but it seems to be possible. For me the results I'm getting with the 5760 dpi mode makes it worth it.

Hi there. I realize I'm resurrecting an old thread, but I'm wondering how this project worked out. I'm trying to use Gutenprint right now to print with a 6-tone B&W inkset with Ubuntu. I'd love to be using QTR but I live in Thailand, and QTR is not compatible with Epson's Asian models, at least the ones I have. It's too bad because the Epson L1800 seems absolutely ideal for black and white printing, because it's basically an Epson 1400 with 'eco-tanks' built in. So no chip resetting at all. Unfortunately, QTR simply won't work with this model through Windows.

I'm struggling with figuring out all the settings in Gutenprint, so I'm curious if this method worked out for you. I'm able to get prints through Gutenprint, but the transitions are way off so my current prints are very poor. I don't really understand all the Gutenprint setting and what I should change.

Quote:

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Originally Posted by EdtheTruth

Hi there. I realize I'm resurrecting an old thread, but I'm wondering how this project worked out. I'm trying to use Gutenprint right now to print with a 6-tone B&W inkset with Ubuntu. I'd love to be using QTR but I live in Thailand, and QTR is not compatible with Epson's Asian models, at least the ones I have. It's too bad because the Epson L1800 seems absolutely ideal for black and white printing, because it's basically an Epson 1400 with 'eco-tanks' built in. So no chip resetting at all. Unfortunately, QTR simply won't work with this model through Windows.

I'm struggling with figuring out all the settings in Gutenprint, so I'm curious if this method worked out for you. I'm able to get prints through Gutenprint, but the transitions are way off so my current prints are very poor. I don't really understand all the Gutenprint setting and what I should change.

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Following up on this thread. I still do believe Gutenprint is a viable option. My main problem at the moment isn't with Gutenprint though but with my Epson 1430 which is giving inconsistent nozzle checks no matter what software I use. That aside I did find a better way to get relative ink densities that avoids the transition issues I was having early on, posting this below so hopefully it helps someone.

Finding transition points- My previous approach to using QTR's calibration sheet to come up with relative ink densities doesn't seem accurate enough, i.e. the transition points always seem to have issues. I have found a method to generate a "calibration sheet" with GP instead.

The basic idea is to modify your printers ink XML files so that for each ink you temporarily map it as the "black" ink. I do this on the default "Six Color Photo" ink definition for my printer (make sure to check it back to defaults after). For each ink channel modify the XML file so that it's now considered black then run `sudo cups-genppdupdate` (in the GutenPrint install directory under /Library/Printers on Mac) to make sure the files are updated.

Next print out your 21 step tablet, but make sure to go to the Gutenprint options before printing and set GCR Lower Bound and GCR Upper Bound to 0. This ensure the printer only prints black ink and since you remapped your black channel to color X you will get a dedicated print-out using your selected ink. Repeat for each ink and now you should have a print out with a 21 step tablet for each channel.

Once you find the transition points, simply put them in your ink xml (described in early post) file under the all-black inkset (MIS Six Tone in my case) run `sudo cups-genppdupdate` again and you should be ready to print.

First many thanks taking care and sharing your knowledge!

I just tried your method but with no success. Some words on my setup: I have an EPSON Stylus Pro 3800 with a home brewed inkset based on the the Carbon 6 -C6b - receipe of Paul Roark (https://www.paulroark.com/BW-Info/In...0Generally.pdf).
I performed an ink separation workflow with QuadToneRIP and created new ink and media entries in the Gutenprint xml files:
- one for the Hextone based ink (more details on request)
- one for my media / ink combination with HGray"X"Value set with the relative density value and HGray"X"Trans values set to 0.5 - best for printer. (more details on request)
The result is already very good.

With the intention to be QuadToneRIP independant I tested your approach. But I must have missed something because my values are completly different from the QTR ones. I tried the following: First I created a media with no curve and no particular entries. I tested different densities with black ink using your method (Six Photo Color) until I got one that have perfect black at 100% and a measurable change at 95%. Already noticeable the 21 steps looks really different from the ones at the QTR ink separation. E.g. 50% ist there much darker. Then I changed the ink channel for each of the other 5 inks (in my case C,LK,LC,LLK,Y). The relatives densities are much higher than the ones from the QTR ink separation process.

Any idea what I'm doing wrong? Help or advice very much appreciated. Many thanks in advance.