Digital BW, The Print

Tyler, Steve,

I ran a test image of a 1" 100% black square four times on the same 
piece of paper. Once on Torchon and once on Hahnemule Photo Rag 
188gsm. I scanned the 8 patches together with my Linoscan 1400 and 
its cheesy software. In Photoshop I applied a levels adjustment layer 
and brought the white and black points in to slightly outside the 
ends of the histogram. I then selected each square and did a 
histogram. Here is what I got:

Torchon: Luminosity - Mean, Std. Dev., Median 

Piezo Ink and Driver: 94.28, 21.88, 90
Piezo Ink and Epson Driver Black Only: 67.26, 9.68, 66
MIS VM Ink and Neutral Curve, Epson Driver RGB: 69.00, 11.40, 67
MIS VM Ink and Epson Driver Black Only: 64.70, 8.81, 64

Hahnemule Photo Rag: Luminosity - Mean, Std. Dev., Median

Piezo Ink and Driver: 89.17, 11.92, 87
Piezo Ink and Epson Driver Black Only: 64.18, 7.50, 63
MIS VM Ink and Neutral Curve, Epson Driver RGB: 64.34, 7.23, 64
MIS VM Ink and Epson Driver Black Only: 64.33, 7.91, 63

This information is obviously meaningless as an absolute value but 
should be a reasonable comparison. On Torchon the MIS VM black is 
slightly darker. On the Photo Rag I would say they are the same. The 
difference in Std Dev on the Torchon is probably surface related.

The Piezo driver must be running more of the lighter inks into the 
black giving a higher luminosity reading.

All this seems to confirm earlier reports that the Piezo and MIS VM 
blacks are very similar. Also confirms that the Piezo inks are 
capable of deeper blacks than the Piezo driver produces.

Hope this is of some use.

Martin


--- In DigitalBlackandWhiteThePrint@y..., "Tyler Boley" <tyler@t...> 
wrote:
> --- In DigitalBlackandWhiteThePrint@y..., sdmey4@a... wrote:
> snip
> > no good blacks with MIS VM BLACK on Jazz or Plush.
> 
> Comparative L values (from LAB Spectrocam measurements)-
> 
> Piezo ink , 3000, RGB driver- 15.14
> Steve's MIS VM, 7000, RGB driver- 20.75
> Old MIS set, 3000, PressReady (probably bumped with the next 
darkest ink)- 15.72
> 
> These were all on Lysonic Fine Art/ Royal Plush. The old MIS 
reading is from an old print I have here from years ago, so it's 
> the old MIS black (there was only one). The workflow from back then 
has gone to workflow heaven, I don't have the 
> specifics.
> The current black in the 7000 is clearly deficient. Any input from 
people experienced with both the Piezo and the MIS on this 
> paper, or Wells River, would help a lot.
> Any comments about the "double density" ink would be apreciated 
also.
> Thanks, Tyler