DN LInearizations adding tone to black point

My DN linearizations are printing negs with some tone in the areas that should be clear. The tone will be preventing me from achieving max Dmax at my standard exposure time.

Walker - this is very similar to what was happening in my previous post where the neg was not printing enough ink for the highlights. You fixed the problem by copying in the first line of each channel from your master curve into my curve and smoothing the resulting curves.

Is it possible to do the same again for the last line of each channel? In my curve, the Y channel and LC and LK channels all have non-zero values in the last line. I can see a thin warm tone on my negative in areas that should be black on the print.

You can see it here in the screenshot of the curve you corrected for the highlights - several channels hit the Y-axis at a non zero point.

I’d be happy to give it a go - could you clarify the process?
Copy a zero value into the last line of Y, LC, and LK channels
Use the original curve as the starting curve and put this new adjusted curve into the curve blending tab. Set the blending amount to be say 25% only in the black end. Smooth the channels at 100%. Copy the resulting new curve.
Repeat a few times until those channels have a final value of zero.

Am I getting close? I don’t want to trash my curves completely by doing the wrong thing.

Many thanks!
David

please save and .zip and private message your linearizer to me with the curve and measurements added. I need to see your settings

-Walker

What was the solution to this? I was making curves that were just fine, using a 129 step target. Switched to a 256 target, and the curve from this is now printing tone in areas that should be clear. All other steps remain the same. Hmm.

Hi Pradip,

The problem was resolved in the following way. Walter suggested that somehow the algorithm had stopped printing the max black. (Perhaps from a glitch that can happen if the white value in a calibration is a “false” value, ie less than than the value of the measurement below it. I’m sure Walter can explain better than me.)
The solution is to set manually the first K value of the curve. For me, a value of 66,000 worked. I then did a couple of new calibrations and the curve began to work well again.

Walter should be able to review your curve and and suggest a similar solution. A hassle for sure but I can be fixed.

All the best
David

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Walker (with a K) thank you.

Yes - Sorry that was an iPhone Typo….