Producing Big 16x20 Negatives (Analog Only)

What are the best and or easiest methods of producing large negatives,
discounting inkjet or digital methods. Do I have to make an internegative
first? The goal is to produce a 16x20 an argyrotype print (monochrome). Thx.
p.s. while I'm on the subject ...how do I do a four colour separation using
darkroom methods.

"Alan Smithee" wrote

p.s. while I'm on the subject ...how do I do a four colour separation
using
darkroom methods.

I take it you are separating into CMYK?

What are you starting with - color negative, transparency,
artwork, color print ...?

What is the final output - transparency, bromoil, dye transfer,
lithograph ...?

--
Nicholas O. Lindan, Cleveland, Ohio
Darkroom Automation
http://www.nolindan.com/da/index.htm
n o lindan at ix dot netcom dot com

"Nicholas O. Lindan" wrote in message
ink.net...
"Alan Smithee" wrote

p.s. while I'm on the subject ...how do I do a four colour separation
using
darkroom methods.

I take it you are separating into CMYK?

What are you starting with - color negative, transparency,
artwork, color print ...?

What is the final output - transparency, bromoil, dye transfer,
lithograph ...?

--
Nicholas O. Lindan, Cleveland, Ohio
Darkroom Automation
http://www.nolindan.com/da/index.htm
n o lindan at ix dot netcom dot com

More interested in the monochrome negatives right now, but sure, can I make
four colour separations in my darkroom with a dichro head? As mentioned in
the original Argryotype for monochrome, I'm probably thinking gum for the
four colour.

Alan Smithee a écrit :

What are the best and or easiest methods of producing large negatives,
discounting inkjet or digital methods. Do I have to make an internegative
first? The goal is to produce a 16x20 an argyrotype print (monochrome). Thx.
p.s. while I'm on the subject ...how do I do a four colour separation using
darkroom methods.

I'm not really an alternative photography specialist but found this
link on argyrotype:
http://www.ephotozine.com/techniques....cfm?recid=135
Looks like you need a real negative with a density range of around 2.2.
So, if you're starting from a negative, you have to make an
"interpositive" enlarged on you final 16x20 negative.
You'll also need to adjust the contrast of the final negative to the
value mentioned above.
Use a step tablet for this job.

I haven't checked the price for 16x20" negatives but I suspect they
should be very high.
I don't know if a paper negative can be used as the exposure light
should be rich in the UV spectrum.

That's one reason why so many use digital negatives (either inkjet or
made through an imagesetter). A second reason, is that they use a mix
of colors, not only black, to increase the UV density of the neg as
most of the alt processes require pretty contrasty with long scale
negatives.

Regarding color separation, it's usually a 3-color separation (also
called trichromy), either RGB or CMY.
Your color head has probably the CMY filters, so you can do it.
It's pretty common with gum and for your gum print you'll have to use
CMY pigments.
The separation is done by exposing 3 negatives each one through one of
the CMY filters, then you'll have to coat your print with one layer
including, say Cyan pigments, expose it with the "cyan" negative,
develop it, and do the same with the magenta and yellow layers.
The exposure and contrast of each negative is important as is the
quantity of pigments in each layer and the way you'll develop them.
Anyway, the lack of precision is part of the interest in such
processes.
I suppose it's easier to start from a positive (a slide) as it already
has a high contrast and no orange mask like with color negatives.

Good luck,
Claudio Bonavolta
http://www.bonavolta.ch

Claudio Bonavolta a écrit :

Alan Smithee a écrit :

What are the best and or easiest methods of producing large negatives,
discounting inkjet or digital methods. Do I have to make an internegative
first? The goal is to produce a 16x20 an argyrotype print (monochrome). Thx.
p.s. while I'm on the subject ...how do I do a four colour separation using
darkroom methods.

I'm not really an alternative photography specialist but found this
link on argyrotype:
http://www.ephotozine.com/techniques....cfm?recid=135
Looks like you need a real negative with a density range of around 2.2.
So, if you're starting from a negative, you have to make an
"interpositive" enlarged on you final 16x20 negative.
You'll also need to adjust the contrast of the final negative to the
value mentioned above.
Use a step tablet for this job.

I haven't checked the price for 16x20" negatives but I suspect they
should be very high.
I don't know if a paper negative can be used as the exposure light
should be rich in the UV spectrum.

That's one reason why so many use digital negatives (either inkjet or
made through an imagesetter). A second reason, is that they use a mix
of colors, not only black, to increase the UV density of the neg as
most of the alt processes require pretty contrasty with long scale
negatives.

Regarding color separation, it's usually a 3-color separation (also
called trichromy), either RGB or CMY.
Your color head has probably the CMY filters, so you can do it.
It's pretty common with gum and for your gum print you'll have to use
CMY pigments.
The separation is done by exposing 3 negatives each one through one of
the CMY filters, then you'll have to coat your print with one layer
including, say Cyan pigments, expose it with the "cyan" negative,
develop it, and do the same with the magenta and yellow layers.
The exposure and contrast of each negative is important as is the
quantity of pigments in each layer and the way you'll develop them.
Anyway, the lack of precision is part of the interest in such
processes.
I suppose it's easier to start from a positive (a slide) as it already
has a high contrast and no orange mask like with color negatives.

Good luck,
Claudio Bonavolta
http://www.bonavolta.ch

I forgot to mention that you can add the black channel by making a 4th
negative without filtering and using black pigments or ink ...

Claudio Bonavolta
http://www.bonavolta.ch

"Alan Smithee" writes:

What are the best and or easiest methods of producing large
negatives, discounting inkjet or digital methods. Do I have to make
an internegative first? The goal is to produce a 16x20 an argyrotype
print (monochrome). Thx. p.s. while I'm on the subject ...how do I
do a four colour separation using darkroom methods.

Digital and an inkjet onto Pictorio OHP is by FAR the best way to go.

Look for `Precision Digital Negative' by, I think, Nelson.

--
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+61 (08) 9257-1001 Kalamunda.
West Australia 6076
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