Light source for Pyro negs

I'm not yet experienced with Pyro development, but I'm considering to give
it a try. My questions concern the enlarger lamp for pringing pyro
negatives. I read frequently that a cold light head is best for pyro
negatives (presumably due to the yellowish stain on the neg), but I have a
standard tungsten halogen lamp in my only enlarger, an Omega D2 with Super
Chromega color head. I hope to use VC paper (Forte and Kodak).

If the spectrum really must be close to that of a cold light head, is there
a filtration offset that can be dialled into on the enlarger's color head
to closely simulate the spectrum of a cold light lamp? Or, with regard to
pringint pyro negs, is the spectral difference between cold light and
tungsten halogen too small to be concerned about?

Regards,
Szabo

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In article ,
Szaboht wrote:

I'm not yet experienced with Pyro development, but I'm considering to give
it a try. My questions concern the enlarger lamp for pringing pyro
negatives. I read frequently that a cold light head is best for pyro
negatives (presumably due to the yellowish stain on the neg), but I have a
standard tungsten halogen lamp in my only enlarger, an Omega D2 with Super
Chromega color head. I hope to use VC paper (Forte and Kodak).



The Chromega is perfectly fine.

If the spectrum really must be close to that of a cold light head, is there
a filtration offset that can be dialled into on the enlarger's color head
to closely simulate the spectrum of a cold light lamp? Or, with regard to
pringint pyro negs, is the spectral difference between cold light and
tungsten halogen too small to be concerned about?

You can use the standard Poly Contrast filter values. Or seamlessly adjust
by varying the Yellow and or Magenta.

7y + 21m = Grade 2 etc.
--
LF Website @ http://members.verizon.net/~gregoryblank

"To announce that there must be no criticism of the President,
or that we are to stand by the President, right or wrong,
is not only unpatriotic and servile, but is morally treasonable
to the American public."--Theodore Roosevelt, May 7, 1918

In article ,
Szaboht wrote:

I'm not yet experienced with Pyro development, but I'm considering to give
it a try. My questions concern the enlarger lamp for pringing pyro
negatives. I read frequently that a cold light head is best for pyro
negatives (presumably due to the yellowish stain on the neg), but I have a
standard tungsten halogen lamp in my only enlarger, an Omega D2 with Super
Chromega color head. I hope to use VC paper (Forte and Kodak).



The Chromega is perfectly fine.

If the spectrum really must be close to that of a cold light head, is there
a filtration offset that can be dialled into on the enlarger's color head
to closely simulate the spectrum of a cold light lamp? Or, with regard to
pringint pyro negs, is the spectral difference between cold light and
tungsten halogen too small to be concerned about?

You can use the standard Poly Contrast filter values. Or seamlessly adjust
by varying the Yellow and or Magenta.

7y + 21m = Grade 2 etc.
--
LF Website @ http://members.verizon.net/~gregoryblank

"To announce that there must be no criticism of the President,
or that we are to stand by the President, right or wrong,
is not only unpatriotic and servile, but is morally treasonable
to the American public."--Theodore Roosevelt, May 7, 1918

Szaboht wrote in message . ..
I'm not yet experienced with Pyro development, but I'm considering to give
it a try. My questions concern the enlarger lamp for pringing pyro
negatives. I read frequently that a cold light head is best for pyro
negatives (presumably due to the yellowish stain on the neg), but I have a
standard tungsten halogen lamp in my only enlarger, an Omega D2 with Super
Chromega color head. I hope to use VC paper (Forte and Kodak).

If the spectrum really must be close to that of a cold light head, is there
a filtration offset that can be dialled into on the enlarger's color head
to closely simulate the spectrum of a cold light lamp? Or, with regard to
pringint pyro negs, is the spectral difference between cold light and
tungsten halogen too small to be concerned about?

Regards,
Szabo


Yes I think the spectral difference of the light source would be a
fairly minor consideration, unless hairsplitting the science is more
interesting that making pictures to you. The stain of a pyro neg acts
as a low contrast filter, for the highlights with VC paper. I don't
think it has any effect on graded paper. The standard tungsten light
source is contrastier than a cold light, so your move to pyro would
definitly smooth out the tonal range. I think you'll love the look. My
landscapes have taken on a far smoother, more realistic and
atmospheric quality. Enjoy.

Szaboht wrote in message . ..
I'm not yet experienced with Pyro development, but I'm considering to give
it a try. My questions concern the enlarger lamp for pringing pyro
negatives. I read frequently that a cold light head is best for pyro
negatives (presumably due to the yellowish stain on the neg), but I have a
standard tungsten halogen lamp in my only enlarger, an Omega D2 with Super
Chromega color head. I hope to use VC paper (Forte and Kodak).

If the spectrum really must be close to that of a cold light head, is there
a filtration offset that can be dialled into on the enlarger's color head
to closely simulate the spectrum of a cold light lamp? Or, with regard to
pringint pyro negs, is the spectral difference between cold light and
tungsten halogen too small to be concerned about?

Regards,
Szabo


Yes I think the spectral difference of the light source would be a
fairly minor consideration, unless hairsplitting the science is more
interesting that making pictures to you. The stain of a pyro neg acts
as a low contrast filter, for the highlights with VC paper. I don't
think it has any effect on graded paper. The standard tungsten light
source is contrastier than a cold light, so your move to pyro would
definitly smooth out the tonal range. I think you'll love the look. My
landscapes have taken on a far smoother, more realistic and
atmospheric quality. Enjoy.

"Szaboht" wrote in message
...

I'm not yet experienced with Pyro development, but I'm
considering to give
it a try. My questions concern the enlarger lamp for
pringing pyro
negatives. I read frequently that a cold light head is
best for pyro
negatives (presumably due to the yellowish stain on the
neg), but I have a
standard tungsten halogen lamp in my only enlarger, an
Omega D2 with Super
Chromega color head. I hope to use VC paper (Forte and
Kodak).

If the spectrum really must be close to that of a cold
light head, is there
a filtration offset that can be dialled into on the
enlarger's color head
to closely simulate the spectrum of a cold light lamp?
Or, with regard to
pringint pyro negs, is the spectral difference between
cold light and
tungsten halogen too small to be concerned about?

Regards,
Szabo

Pyro developers produce a stain image that acts to
intensify the silver image. The printing contrast is higher
than the visual contrast. The stain image is yellowish and
blocks blue light. Its effect depends mostly on the spectral
sensitivity of the paper.
Most cold light heads are quite blue, although there are
some that approximately duplicate tungsten light for use
with variable contrast filters. I think the idea that the
cold light head is preferable comes from this. However, if
the paper sees only blue light the spectral output of the
printing light doesn't matter.
Now, when variable contrast paper is used with pyro
negatives there is some tendency for the stain image to act
as a contrast reducing filter for the highlights. This may
or may not be desirable since low contast highlights make
prints look flat. The spectral distribution of the printing
light will make some difference if VC paper is used the lack
of green light tending to _increase_ contrast. Note that the
low contrast filters for variable contrast paper are yellow
while the high contrast filters are magenta. Yellow blocks
blue light, magenta blocks green. All this is getting away
from the point. If you print on graded paper the spectral
content of the printing light will make little difference
because the paper has a relatively limited spectral
sensitivity which is centered in the range where the Pyro
stain image is most effective.
Blue cold light heads screw up variable contrast
filtering anyway. Color heads and condenser heads are quite
suitable for Pyro negatives. Just don't expect magic. I
suspect many who rave about Pyro are getting better
negatives because they are paying more attention to
controlling all the variables.


--
---
Richard Knoppow
Los Angeles, CA, USA

"Szaboht" wrote in message
...

I'm not yet experienced with Pyro development, but I'm
considering to give
it a try. My questions concern the enlarger lamp for
pringing pyro
negatives. I read frequently that a cold light head is
best for pyro
negatives (presumably due to the yellowish stain on the
neg), but I have a
standard tungsten halogen lamp in my only enlarger, an
Omega D2 with Super
Chromega color head. I hope to use VC paper (Forte and
Kodak).

If the spectrum really must be close to that of a cold
light head, is there
a filtration offset that can be dialled into on the
enlarger's color head
to closely simulate the spectrum of a cold light lamp?
Or, with regard to
pringint pyro negs, is the spectral difference between
cold light and
tungsten halogen too small to be concerned about?

Regards,
Szabo

Pyro developers produce a stain image that acts to
intensify the silver image. The printing contrast is higher
than the visual contrast. The stain image is yellowish and
blocks blue light. Its effect depends mostly on the spectral
sensitivity of the paper.
Most cold light heads are quite blue, although there are
some that approximately duplicate tungsten light for use
with variable contrast filters. I think the idea that the
cold light head is preferable comes from this. However, if
the paper sees only blue light the spectral output of the
printing light doesn't matter.
Now, when variable contrast paper is used with pyro
negatives there is some tendency for the stain image to act
as a contrast reducing filter for the highlights. This may
or may not be desirable since low contast highlights make
prints look flat. The spectral distribution of the printing
light will make some difference if VC paper is used the lack
of green light tending to _increase_ contrast. Note that the
low contrast filters for variable contrast paper are yellow
while the high contrast filters are magenta. Yellow blocks
blue light, magenta blocks green. All this is getting away
from the point. If you print on graded paper the spectral
content of the printing light will make little difference
because the paper has a relatively limited spectral
sensitivity which is centered in the range where the Pyro
stain image is most effective.
Blue cold light heads screw up variable contrast
filtering anyway. Color heads and condenser heads are quite
suitable for Pyro negatives. Just don't expect magic. I
suspect many who rave about Pyro are getting better
negatives because they are paying more attention to
controlling all the variables.


--
---
Richard Knoppow
Los Angeles, CA, USA

Szaboht wrote in message . ..
I'm not yet experienced with Pyro development, but I'm considering to give
it a try. My questions concern the enlarger lamp for pringing pyro
negatives. I read frequently that a cold light head is best for pyro
negatives (presumably due to the yellowish stain on the neg), but I have a
standard tungsten halogen lamp in my only enlarger, an Omega D2 with Super
Chromega color head. I hope to use VC paper (Forte and Kodak).

If the spectrum really must be close to that of a cold light head, is there
a filtration offset that can be dialled into on the enlarger's color head
to closely simulate the spectrum of a cold light lamp? Or, with regard to
pringint pyro negs, is the spectral difference between cold light and
tungsten halogen too small to be concerned about?

Regards,
Szabo

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The 'benefit' of a stained negative is the stain, which takes the
place of silver density for papers that are sensitive only to blue.
The stain is yellowish-green, and since these stains block blue light,
they are seen as extra density by blue-sensitive paper. Variable
contrast paper DOES see 'green', and so the stain DOES NOT act as
density for VC papers.

Use and GRADED paper to get the 'benefits' of pyro. The light source
does not matter so much. DO NOT use VC paper, because it defeats the
whole purpose of pyro.

The stain is without grain and has a nicer gradation of tone than
silver has, but again, only for graded (blue-sensitive) paper. A
negative correctly developed in pyro has a rather 'thin' silver base
which the stain supplements. If the stain were to be removed, the
silver density of a properly-developed pyro negative would be seen as
too flat and thin. It's supposed to be that way, because the stain
assists in providing enough PRINTING density to give a good print.

"Uranium Committee" wrote in message
om...


The 'benefit' of a stained negative is the stain, which takes the
place of silver density for papers that are sensitive only to blue.
The stain is yellowish-green, and since these stains block blue light,
they are seen as extra density by blue-sensitive paper. Variable
contrast paper DOES see 'green', and so the stain DOES NOT act as
density for VC papers.

Use and GRADED paper to get the 'benefits' of pyro. The light source
does not matter so much. DO NOT use VC paper, because it defeats the
whole purpose of pyro.


This information is completely wrong.

"Uranium Committee" wrote in message
om...


The 'benefit' of a stained negative is the stain, which takes the
place of silver density for papers that are sensitive only to blue.
The stain is yellowish-green, and since these stains block blue light,
they are seen as extra density by blue-sensitive paper. Variable
contrast paper DOES see 'green', and so the stain DOES NOT act as
density for VC papers.

Use and GRADED paper to get the 'benefits' of pyro. The light source
does not matter so much. DO NOT use VC paper, because it defeats the
whole purpose of pyro.


This information is completely wrong.