Digital BW, The Print

Paul,

Very good points.

The distribution of density values per my Stouffer Calibrated Table are....

Step21= 3.06
Step20= 2.91
Step19= 2.76
Step18= 2.61
Step17= 2.47
Step16= 2.32
Step15= 2.17
Step14= 2.02
Step13= 1.87
Step12= 1.72
Step11= 1.56
Step10= 1.40
Step 9 = 1.25
Step 8 = 1.10
Step 7 = .94
Step 6 = .79
Step 5 = .64
Step 4 = .49
Step 3 = .34
Step 2 = .19
Step 1 = .04

Now obviously this is a transmission strip and there is no way we will get a
density range of 3.02 with ink on paper!
But assuming we are getting a DR of 0 to 1.72 then each step should be
uniform in difference. I think that your curves tend to do this, but the
Piezo software does not.

In platinum printing we get a DR of 1.8 for a normal platinum print. A
normal silver print has a DR of approximately 1.2.

I never checked the DR of a Piezo Print. Perhaps you can read that on your
densitimeter and see what you get. I believe it will be close to platinum or
possible exceed it.

Mike


----- Original Message -----
From: "Paul Roark" <paul.roark@...>
To: "DigitalB&WPrint" <DigitalBlackandWhiteThePrint@yahoogroups.com>
Sent: Sunday, March 24, 2002 11:47 AM
Subject: [Digital BW] What is "linear" -- was For Della On Shadows


> Mike,
>
> You wrote, in part:
>
> >In an ideal world, ... I want software that produces a linear
> >distribution of tones. ...
>
> This may sound like a silly or loaded question, but it really is not.
>
> What is a "linear" distributing of tones?
>
> I essentially copied the average Piezo output in terms of what the "50%"
> density  should be because I wanted to be able to use either output
> approach -- Piezo or variable-tone -- for the same file.  However, it's
hard
> to know how that 50% point or gamma was arrived at or what it "should" be.
>
> If someone has a good theoretical explanation of how Cone came up with his
> "50%" value/gamma setting, I'd sure like to hear it.
>
> This is the chart I came up with that seemed to match the "gamma" setting
> that Piezo uses and that I, therefore, use for the curves I do.
>
> The RGB is close to AdobeRGB (now), using the 0-255 scale.  The black is
> about what I get with the 3000 using VM black and Back Lit film media
type,
> printed on EAM.  This figure can be up to 1.70, depending on what mood the
> printer is in that day.  The white (0%) point is for new EAM.  The density
> readings are "visual" density as read by the X-Rite Digital Swatchbook.
>
>  %   RGB  Density
> ___  ___   _____
>
> 100% = 0 = 1.68
> 95% = 12 = 1.53
> 90% = 25 = 1.38
> 85% = 38 = 1.25
> 80% = 51 = 1.13
> 75% = 64 = 1.03
> 70% = 77 = .93
> 65% = 90 = .84
> 60% = 102 = .76
> 55% = 115 = .68
> 50% = 128 = .61
> 45% = 141 = .54
> 40% = 154 = .47
> 35% = 165 = .41
> 30% = 178 = .35
> 25% = 191 = .29
> 20% = 204 = .24
> 15% = 217 = .19
> 10% = 229 = .14
> 5%  = 242 = .09
> 0%  = 255 = .04 (EAM)
>
> Paul
> http://www.PaulRoark.com
>
>
>
>
>
>
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