February 2006 Alt-Photo-Process-L: Fwd: spectral sensitivity of

From: Ender100@aol.com
Date: 02/21/06-01:44:57 PM Z
Message-id: <1da.4d31ac59.312cc7b9@aol.com>

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Date: Tue, 21 Feb 2006 14:43:08 EST
From: Ender100@aol.com
Subject: Re: spectral sensitivity of platinum/palladium and cyanotype coatings.
To: alt-photo-process-l@sask.usask.ca
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I agree with Clay regarding the fact that green negatives are commonly being=
=20
used. =20

However, in spite of what Kermit says, i.e., "It's not easy being Green",=20
there is actually nothing magical about the color green. What is most impo=
rtant=20
is that each inkset (dye, pigment, ultrachromes, K3, etc etc) has its own=20
"signature", or variation of which colors provide what densities. What is mo=
st=20
important is to match the Color Density to the Exposure Scale of whatever al=
t=20
process you are using.

So it isn't so much that these processes "like" or "long for" or even "lus=
t=20
for" a green negative=E2=80=94the issue is that for the most part some versi=
on of a=20
green negative with many of the printer ink combinations provides the UV=20
DENSITY that happens to match the exposure scale of the contrast mix being u=
sed with=20
PT/PD, Van Dyke Brown, Kallitype, Cyanotype , etc. If you were to lower the=20
contrast mix of say Palladium, you would probably find a different color you=
=20
could also use quite successfully. This is what the PDN system is based on=
=E2=80=94it=20
is an outcome based system that determines the proper color density for you=20
based on the RESULTS with the Alt Process/Contrast=20
Mix/Paper/Exposure/Humidity/Workflow/Underwear that you are using.

I am currently testing a new prototype film for a major manufacturer that I=20
am able to load quite heavily with ink using the ink configuration setting i=
n=20
the Epson Driver set all the way up to +50 without any signs of puddling,=20
increased pizza wheels tracks, smearing, or loss of sharpness=E2=80=94and it=
comes out of=20
the printer dry! This is giving a boost of UV density to the negatives of=20
over Log 4.0 when measured with a UV densitometer, which is about 5 stops=20
increase in density for a given Color Density. I have no doubt that I coul=
d make a=20
very successful negative for Palladium that would use some color other than=20
green.

One caveat is that there is often more than one Standard Color Density that=20
can be used to craft a negative for a given alt process=E2=80=94in some case=
s due to=20
the combination of inks involved, you may see more "noise" or apparent ink g=
rain=20
due to the differential in density of the inks comprising that specific=20
color.

What is quite interesting to me is the indication that some alt processes ar=
e=20
not just sensitive to UV light, but also the visible light spectrum. You=20
can find some unusual anomalies with some processes, such as with one poly=
mer=20
plate for photogravure that prints equally well with two different colors th=
at=20
measure a full stop difference in UV density=E2=80=94yet they print with the=
same=20
exact density. So something else is going on within the visible light spec=
trum,=20
in addition to the UV spectrum. =20

I think we are going to learn more and more about these processes using thes=
e=20
new methods of crafting negatives.

As an aside, Terry (AKING), last we talked you were pretty well convinced=20
that the only way to make digital negatives was with an imagesetter=E2=80=
=94what has=20
changed your mind?

Best Wishes,
Mark I. Nelson
www.MarkINelsonPhoto.com
www.PrecisionDigitalNegatives.com
PDNPrint Forum @ Yahoo Groups

In a message dated 2/21/06 8:14:27 AM, wcharmon@wt.net writes:

>=20
> The fact that green negatives=C2=A0 are=C2=A0most efficient at blocking UV=
is old news=20
> for many of us. There are at least three different approaches that have go=
ne=20
> way beyond idle speculation and have proven this empirically.
>=20
>=20
>=20
>=20
> Mark Nelson's system, Keith Schreiber's investigations and my Ternary=20
> diagram approach to discerning=C2=A0UV spectral density all generally end=20=
up showing=20
> that greenish ink colors tend to be the most efficient at blocking UV ligh=
t.
>=20
>=20
>=20
>=20
> see:
>=20
>=20
>=20
>=20
> http://www.precisiondigitalnegatives.com/
>=20
>=20
>=20
>=20
> and=C2=A0
>=20
>=20
>=20
>=20
> http://www.zianet.com/jkschreiber/articles/1280PyroDigiNegs.html
>=20
>=20
>=20
>=20
> and
>=20
>=20
>=20
>=20
> http://www.alternativephotography.com/articles/art056.html
>=20
>=20
>=20
>=20
> As far as implications for spectral sensitivity of pt/pd, I would surmise=20
> that it says very little. The UV blocking characteristics of printer ink h=
as=20
> more to do with the characteristics of the ink itself than with the platin=
um=20
> process per se.=C2=A0
>=20
>=20
>=20
>=20
> In the end, it doesn't really matter, since it is trivial to find out whic=
h=20
> colors are most efficient at blocking UV light for your chosen process.
>=20
>=20
>=20
>=20
> Clay
>=20
>=20
>=20
>=20
>=20
>=20
>=20
>=20
>=20
>=20
> Quote:
>=20
>=20
>=20
>=20
> In an Il Laborario meeting recently, David Harris suggested using green in=
ks=20
> rather than red for making negatives on Translucent II. This seemed to wor=
k=20
> very well for platimum/palladium solutions. What do people consider=C2=A0=20=
the=20
> implications of this to be for the spectral sensitivity of platinum/pallad=
ium ?
>=20
>=20
>=20
> =3D
>=20

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Content-type: text/html; charset=UTF-8
Content-language: en
Content-transfer-encoding: QUOTED-PRINTABLE

<HTML><HTML>I agree with Clay regardi=
ng the fact that green negatives are commonly being used.  
 
However, in spite of what Kermit says, i.e., "It's not easy being Gre=
en", there is actually nothing magical about the color green.  =
What is most important is that each inkset (dye, pigment, ultrachrome=
s, K3, etc etc) has its own "signature", or variation of which colors=
provide what densities. What is most important is to match the Color=
Density to the Exposure Scale of whatever alt process you are using.=
 
 
So it isn't so much that these  processes "like" or "long for" =
or even "lust for" a green negative=E2=80=94the issue is that for the=
most part some version of a green negative with many of the printer =
ink combinations provides the UV DENSITY that happens to match the ex=
posure scale of the contrast mix being used with PT/PD, Van Dyke Brow=
n, Kallitype, Cyanotype , etc. If you were to lower the contrast mix =
of say Palladium, you would probably find a different color you could=
also use quite successfully.  This is what the PDN system is b=
ased on=E2=80=94it is an outcome based system that determines the pro=
per color density for you based on the RESULTS with the Alt Process/C=
ontrast Mix/Paper/Exposure/Humidity/Workflow/Underwear that you are u=
sing. 
 
I am currently testing a new prototype film for a major manufacturer =
that I am able to load quite heavily with ink using the ink configura=
tion setting in the Epson Driver set all the way up to +50 without an=
y signs of puddling, increased pizza wheels tracks, smearing, or loss=
of sharpness=E2=80=94and it comes out of the printer dry!  Thi=
s is giving a boost of UV density to the negatives of over Log 4.0 wh=
en measured with a UV densitometer, which is about 5 stops increase i=
n density for a given Color Density.  I have no doubt that I co=
uld make a very successful negative for Palladium that would use some=
color other than green. 
 
One caveat is that there is often more than one Standard Color Densit=
y that can be used to craft a negative for a given alt process=E2=
=80=94in some cases due to the combination of inks involved, you may =
see more "noise" or apparent ink grain due to the differential in den=
sity of the inks comprising that specific color. 
 
What is quite interesting to me is the indication that some alt proce=
sses are not just sensitive to UV light, but also the visible light s=
pectrum.  You can find some unusual  anomalies with some =
processes, such as with one polymer plate for photogravure that print=
s equally well with two different colors that measure a full stop dif=
ference in UV density=E2=80=94yet they print with the same exact dens=
ity.  So something else is going on within the visible light sp=
ectrum, in addition to the UV spectrum.  
 
I think we are going to learn more and more about these processes usi=
ng these new methods of crafting negatives. 
 
As an aside, Terry (AKING), last we talked you were pretty well convi=
nced that the only way to make digital  negatives was with an i=
magesetter=E2=80=94what has changed your mind? 
 
Best Wishes, 
Mark I. Nelson 
www.MarkINelsonPhoto.com 
www.PrecisionDigitalNegatives.com 
PDNPrint Forum @ Yahoo Groups 
 
 
In a message dated 2/21/06 8:14:27 AM, wcharmon@wt.net writes: 
 
 
<BLOCKQUOTE CITE STYLE=3D"BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT=
: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px" TYPE=3D"CITE"><FO=
NT COLOR=3D"#000000" FACE=3D"Geneva" FAMILY=3D"SANSSERIF" SIZE=3D"2">=
 
The fact that green negatives=C2=A0 are=C2=A0most efficient at blocki=
ng UV is old news for many of us. There are at least three different =
approaches that have gone way beyond idle speculation and have proven=
this empirically. 
 
 
 
 
Mark Nelson's system, Keith Schreiber's investigations and my Ternary=
diagram approach to discerning=C2=A0UV spectral density all generall=
y end up showing that greenish ink colors tend to be the most efficie=
nt at blocking UV light. 
 
 
 
 
see: 
 
 
 
 
<A HREF=3D"http://www.precisiondigitalnegatives.com/">http:=
//www.precisiondigitalnegatives.com</A>/ 
 
 
 
 
and=C2=A0 
 
 
 
 
<A HREF=3D"http://www.zianet.com/jkschreiber/articles/1280P=
yroDigiNegs.html">http://www.zianet.com/jkschreiber/articles/1280Pyro=
DigiNegs.html</A> 
 
 
 
 
and 
 
 
 
 
<A HREF=3D"http://www.alternativephotography.com/articles/a=
rt056.html">http://www.alternativephotography.com/articles/art056.htm=
l</A> 
 
 
 
 
As far as implications for spectral sensitivity of pt/pd, I would sur=
mise that it says very little. The UV blocking characteristics of pri=
nter ink has more to do with the characteristics of the ink itself th=
an with the platinum process per se.=C2=A0 
 
 
 
 
In the end, it doesn't really matter, since it is trivial to find out=
which colors are most efficient at blocking UV light for your chosen=
process. 
 
 
 
 
Clay 
 
 
 
 
 
 
 
 
 
 
Quote: 
 
 
 
 
In an Il Laborario meeting recently, David Harris suggested=
using green inks rather than red for making negatives on Translucent=
II. This seemed to work very well for platimum/palladium solutions. =
What do people consider=C2=A0 the implications of this to be for the =
spectral sensitivity of platinum/palladium ? 
 
 
 
=3D 
</BLOCKQUOTE> 
 
 
 
 
 
</HTML>

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Received on Tue Feb 21 13:45:42 2006

Fwd: spectral sensitivity of platinum/palladium and cyanotype coatings.