Relinearize QTR Quad Files
THe only Service of its kind That allows you to bypass the QTR linearization Stage or Relinearize your existing Quad Files for new Papers
With this service you are able to upload your original .quad file and a measurement file of a 51-step target printed with that profile, and then receive a corrected QTR Quad file linearized to either a linear Lab_L target, or one with slightly compressed shadows.
This could be UC K3 profiles, Eboni-6 profiles made with the QTR curve creation tools, or existing Piezography profiles.
Features and Benefits
Those familiar with creating custom QTR profiles know that one of the most common problems is the potential for errors in the linearization step. There can be many reasons for these kinds of errors, but solving this problem on your own can be a frustrating cycle of printing a target, measuring it, running into the error, editing the profile, and reprinting the target, again and again... Sometimes the problem might just be that your densities are just a little too close for the QTR curve creation script to work with, or that they might actually be reversed in some places. With this service it doesn't matter how close your measurements are from one patch to the next, or if they are "not constantly increasing" as the QTR error will say.
In addition to correcting for hard-to-linearize profiles, this can also be used if you already have a perfectly linear profile but would like to increase the shadow densities to better match your screen without the blocked up shadows often created when printing with an ICC profile and using a rendering intent with black point compensation. When you choose the Option "Slightly Compressed Shadows," you will receive a relinearized quad curve file that increases the shadow density from about 60%-100%. This adjustment is fine-tuned by hand each time to ensure that the shadows remain smooth and open. It might not look like much, but it results in a richer feeling print compared to the default linear QTR profile.
HOW IS THIS DIFFERENT THAN WHAT INK JET MALL OFFERS WITH CUSTOM PIEZOGRAPHY PROFILES?
This service as an affordable alternative for people who can print and measure their own 51-step target. My method doesn't require printing and mailing a full 256 step grayscale file that their PiezoProfiler requires, and while my correction curve and quad value interpolation method is very good and extensively tested, it does not work with the same kind of lookup table for determining the final quad values.
This is meant as a way to affordably test new papers, correct for printer problems, or just map the existing linear profile to one with a slightly richer shadow curve that doesn't create the blocked up shadows that occur when printing with an ICC profile and Black Point Compensation.
WHY A 51X3 MEASUREMENT FILE?
I've tested this with the 21x4 random target included with QuadToneRIP and found that 21 data points is not enough to correct for the small bumps that often occur when using so many overlapping inks. I've determined that 51 control points allow enough precision for the functions to work accurately, without being too arduous to print and measure. However, there are always small errors in measurements of the same patch and/or target, and I've found that averaging three different measurements of the same printed target is sufficient to smooth out any measurement errors. It is better to measure the same target three times than to print three targets and measure each target once.
You can download the 51x3 reference file for X-Rite's ProfileMaker5 MeasureTool and measure the 51-step target included with QuadToneRIP. For those with Mac OSX Lion and later, I've created an i1 Profiler workflow and updated 51-step target that works with the i1Pro photospectrometer. You can download these at the link below. Those with the Spyder Print photospectrometer can print the current 51-step target and use the reference file included with QTR to measure and save three separate measurement files.
Alternatively, for an small additional charge, you can mail me the printed target for me to measure. The page to upload your quad curves and instructions for mailing your printed target is here: http://www.bwmastery.com/quadlin-mail-target
SPYDERPRINT OR X-RITE PROFILEMAKER5 MEASURETOOL
Print the Step-51-gray.tif using the QTR Curves you want to relinearize.
Download the special reference file to measure the QTR-51-step grayscale three times.
Measure the 51-step target three times and save the measurement file with the same name as the quad curve and include 51x3 at the end of the file name before the .txt extension.
Upload the Original Quad Curve File and the Measurement File of the 51-step target using the form below.
Download and extract the i1Profiler 51x3 workflow folder.
Follow the instructions here for printing and measuring the updated 51-step target for i1 Profiler.
- Upload the Original Quad Curve File and the Measurement File of the 51-step target using the form below.
Can't find your .quad files?
These QuadToneRIP curves are buried in the system folders and can be found by navigating to the file path below:
- Mac: Macintosh HD/Library/Printer/QTR/quadtone/
- Windows: c:\Program Files\QuadToneRIP\QuadTone
- Choose the folder for you printer model and ink set ex: Quad3800 or Quad1430-MIS
- You can then drag the quad file you want to relinearize to the field in the upload form below
Still have questions?
Use this contact form for any additional questions about this service or for help with any of the steps.