RE: Inkjet negatives and Van Dyke Brownprints

Although I am more interested at this point in printing with
kallitype (ferric oxalate variety) and pure palladium I have
nevertheless both tested VDB and made a few nice prints with it using
the same basic curve that I use for the above processes. I have
created two different curves that work together very well for
kallitype, palladium and VDB, both derived from Mark Nelson's PDN
methods. One is based on a colorized negative, the emerald green
negative as I call it, and the other on printing a RGB file in color,
but desaturating the file so that the end result is a neutral black
negative. This gives a bit more contrast than the colorized negative
in case you might want it. Output is on the Epson 2200 and I always
set the media to glossy photo paper. I am including the PS input and
output values for the two curves below. As you can see, my numbers
are significantly different from what others have indicated.

First, the PS input and output numbers for the colorized negative.

  255 255
  242 152
  230 125
  217 113
  204 105
  191 97
  179 84
  166 83
  153 78
  140 73
  128 68
  115 63
  102 59
  89 54
  77 48
  64 45
  51 40
  38 36
  26 22
  13 8
  - -

And then the PS input and output numbers for the neutral black negative.
  255 255
  242 161
  230 133
  217 115
  204 102
  191 92
  179 84
  166 77
  153 69
  140 64
  128 59
  115 54
  102 48
  89 43
  77 38
  64 34
  51 31
  38 26
  26 20
  13 11

These values produce very nice prints, with good shadow, mid-tones
and highlights with both kallitype and pure palladium (for an
exposure scale of about 1.85, and it also works nicely with VDB. The
second curve, based on neutral black ink, gives slightly more
contrast and might be a tad better if all you do is VDB since the ES
of VDB with the classic mix is slightly higher than that of kallitype
and pure palladium.

Sandy

>Joe,
>
>> Thanks for the pointer to Gary's site. I had seen it and read the
>> article. But, it only adds to my bewilderment about the severity of
>> the correction curves. Look at Gary's curve values compared to mine:
>>
>> input...Gary's output...My output
>> 225...222...133
>> 190...190...118
>> 156...162...103
>> 120...138...93
>> 90...121...85
>> 44...90...72
>> 20...61...64
>> 0...24...54
>>
>> His range of values in the corrected negative is almost 200 levels while
>> mine is compressed to around 80 levels. We are both clipping the high
>> and low ends but my clipping is much more severe on both ends and the
>> curve much lower in contrast. I've tried my curve with a couple
>> different images and get similar (and nearly acceptable) results from
>> the negatives. I'm perplexed.
>>
>
>Have you printed a digital step wedge?
>
>Dan's 50 patch step tablet is a good one to use or Liam Lawless's 101 patch
>tablet may even be better. Printed along side a standard Stouffers step
>tablet can help lead you in the right direction perhaps. I would print these
>uncurved to start with and evaluate the results. Sometimes using someone
>else's curve doesn't really help.
>
>A colorized negative will most likely help to reduce the need for an extreme
>adjustment curve. You mat even want to try Keith Schreiber's faux pyro
>color.
>
>Don
Received on Fri Nov 19 10:26:59 2004