Digital BW, The Print

Given two reported failures in the field on top of the three fade tests conducted by Paul Roark which consistently showed very rapid fading and warming of the PiezoTone black ink, I strongly recommend that you stop using either the Selenium PiezoTone or Warm-Neutral PiezoTone inks until the issue has been clarified and/or corrected. It appears that the PiezoTone black ink potentially can warm and fade to the point of extreme image degradation within a very short display time. Whether this is limited to a specific batch of ink, manufacturing defect or some other cause, is unknown.

This is extremely disappointing as I have found the Selenium PiezoTone ink set to be my favorite in terms of hue and tonal rendition and I have produced a large number of prints with the ink over the past few weeks.

The problem appears to be isolated to the black ink in the set and the gray inks appear to be fine. In fact in Paul Roark's testing the gray inks gave some of the very best mid tone performance to date.

As an alternative to stopping use of these ink sets completely, I have tried a substitution of MIS Neutral Full Spectrum black ink in the Selenium PiezoTone ink set. This appears to work quite well in step wedges and in test prints. I do not see any shift in hue. Unfortunately the Dmax of the FS black is not as high as the PiezoTone black. One positive effect of the decreased Dmax however is that it seems to be a better match for the existing PiezoBW paper profiles giving less compacted results in the lower tones. However, even with these drawbacks, I prefer the Selenium PiezoTone inks with the FS black over the other PiezoBW/R9 compatible inks for its hue. This makes a very neutral ink set.

Dmax on EAM was 1.69 for the PT-black and 1.59 for the FS-black.
Dmax on Photo Rag was 1.84 for the PT-black and 1.68 for the FS-black.

In test prints I noticed that prints optimized for the standard Selenium PiezoTone ink set on Photo Rag required small adjustments in contrast and/or brightness. One way to adjust this difference is to add two Brightness/Contrast layers at the top of the image. Set one for +5 Contrast and the other for -5 Brightness. If these are not appropriate for all print areas paint in masks on these to layers to control the effected portions of the print. Some of you will no doubt think of some better methods.

Another possible black ink that would match the PiezoTone black Dmax but not meet the FS black fade resistance would be the Generations 4 black. I hope to do some trials with this later in the week and will pass on what I find.

You will find spectrophotometer readings of test wedges below but given the text nature of the Yahoo groups the data may be difficult to follow. I have posted the data and a graph in the Files section of the Digital B&W group homepage in folder:

Files > Ink Sets > PiezoTones



      Dot % Sel-PT w/PT-K on EAM Sel-PT w/MIS-FSN-K on EAM Sel-PT w/PT-K on Photo Rag Sel-PT w/MIS-FSN-K on Photo Rag 
      100% 1.69 1.59 1.84 1.68 
      99% 1.66 1.57 1.77 1.64 
      98% 1.65 1.55 1.73 1.62 
      97% 1.62 1.53 1.69 1.57 
      96% 1.61 1.49 1.66 1.56 
      95% 1.58 1.47 1.64 1.52 
      90% 1.46 1.38 1.48 1.40 
      85% 1.32 1.27 1.32 1.28 
      80% 1.19 1.18 1.22 1.20 
      75% 1.10 1.09 1.15 1.11 
      70% 1.01 1.00 1.06 1.03 
      65% 0.92 0.91 0.97 0.94 
      60% 0.82 0.82 0.87 0.85 
      55% 0.74 0.73 0.80 0.77 
      50% 0.68 0.68 0.73 0.70 
      45% 0.62 0.62 0.65 0.63 
      40% 0.56 0.57 0.60 0.58 
      35% 0.50 0.51 0.52 0.51 
      30% 0.44 0.45 0.45 0.43 
      25% 0.38 0.39 0.39 0.38 
      20% 0.32 0.33 0.32 0.32 
      15% 0.26 0.26 0.25 0.25 
      10% 0.19 0.20 0.19 0.19 
      5% 0.12 0.12 0.12 0.12 
      0% 0.06 0.06 0.06 0.06 

Martin Wesley

http://www.borderless-photos.de/guests.html





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