Linearize with flatbed scanner?

I copied A1 through D137 into Notepad and saved them as a txt file (cool.txt, neutral.txt, and warm.txt), then put them on the Desktop along with the cool, neutral, and warm quad files, then selected both “cool” files and dragged them over the QTR-Linearize-Quad droplet and I got a “cool-lin.quad”. Then I did the same for the neutral pair and got a neutral-lin.quad file, but when I followed the same procedure with the warm pair (warm.txt and warm.quad) it generated a “warm-out.txt” file, not the “warm-lin.quad” I expected. Attached are the two files in question - can anybody point out what I’m doing wrong here?

warm-1.zip (3.25 KB)

You have a reversal on line 118 and 119 probably due to an improperly typed in L* value.

 

best,

Walker

I saw that the values on the two lines seemed reversed so I re-wrote lines 117, 118, and 119 so that the numerical values are descending but after dropping them both on the QTR-Linearize-Quad droplet I still end up with a file named “warm3-out.txt” instead of “warm3-lin.quad”, like the first two. Any more ideas?

warm2.zip (3.25 KB)

As I said, you need to look at the numbers that you type into the 21step tool. It’s somewhere in there that the reversal happens. Probably 2 numbers are very close together, no?

 

best,

Walker

Probably 2 numbers are very close together, no? Yes, there were two cells with the same value. I changed one and I got the -lin.quad file. Thanks for everything!

In the manual concerning printing the 21-step target it says:

  1. Open the file in Photoshop. Go to Camera Raw Filter and do a Luminance noise
    reduction at 100% strength.

  2. Add a curve layer. Select the black dropper and click the darkest patch to make it
    totally black. You may have to bring the black datapoint in just a bit past where it is to
    fully make the blackest printed patch 100% black.

  3. Select the white dropper and click the whitest patch (or paper white) to make it totally
    white.

…but when using the Piezography Error Corrector to print a 51-step target it says:

  1. Print and let dry a 51 step Piezography target with your desired QuadtoneRIP curve using No Color Management.

  2. Read the target with the device of your choosing

  3. Measure your 51 Step Chart with your hardware of choice.

Does this mean that when using the Piezography Error Corrector to print a 51-step (or 129-step) target the noise reduction and curve layers are unnecessary ?

When using the Piezography Error Corrector you must have a spectrophotometer (not a scanner). Doing anything in photoshop is not necessary when dealing with a spectrophotometer.

 

best,

Walker