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QTR-Quadtone RIP

Index last updated: 2026-04-28 23:12 UTC

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Re: Calculating Ideal Density

2017-01-30 by richard@...

The short answer is that the ideal densities are being calculated from the Linear Lab L* values. That requires one additional conversion from reflectance percentage to XYZ_Y to Lab_L to calculate the ideal linear densities for each 5% step.

Here is a dropbox link to a spreadsheet tool I made a while back that does that conversion for you: The formulas are

https://www.dropbox.com/s/nrcxze38fmbruiu/BWMASTERY%20Lab%20to%20Density%20Conversion%20Tool.xlsx?dl=0



I converted the densities from your post to Lab L* and pasted them below. If you graph them you'll see that the ideal one from the ideal density PDF is a straight line, and yours is a curved line (that would print too light compared to the QTR Linear Standard).

Step My ID 0 100 100 5 98.05771213 95.80416674 10 96.06190196 91.5948099 15 94.01654174 87.38510882 20 91.84284155 83.18773869 25 89.6309833 79.01481401 30 87.30578826 74.808114 35 84.8768059 70.58805598 40 82.27838004 66.37422138 45 79.60002134 62.1852188 50 76.70958903 57.9817595 55 73.63094787 53.78969857 60 70.32262847 49.58300658 65 66.81798427 45.34671649 70 62.90865773 41.16426922 75 58.55177521 36.98154954 80 53.68264961 32.76684459 85 47.99184854 28.54421631 90 41.03279505 24.34514889 95 31.76663589 20.15136133 100 15.94905296 15.94905296


Hope that helps,
Richard Boutwell

http://www.richardboutwell.com/




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