split filter paper developing

I used to have an article from Zone VI Studios about split filter paper developing. I moved, and can't find the directions. Anybody have some help on this please?


--
foto phred

------------------------------------------------------------------------
View this thread: http://www.photographytalk.net/viewtopic-171060.html

Send from http://www.photographytalk.net

"foto phred"
wrote in message
...

I used to have an article from Zone VI Studios about split
filter paper developing. I moved, and can't find the
directions. Anybody have some help on this please?


--
foto phred

------------------------------------------------------------------------
View this thread:
http://www.photographytalk.net/viewtopic-171060.html

Send from http://www.photographytalk.net

I think you are asking about a method that is supposed
to change the gray scale of the paper. It doesn't work and
is based on a misunderstanding of how variable contrast
papers work.
One can get intermediate grades of contrast by printing
part of the time through a high contrast filter and a low
contrast filter but the results will be no diffent than
gotten with a single filter of the correct grade. There will
be no change in the relative contrast of shadow and
highlight areas. The contrast of vc paper is determined by
the relative exposure of a high and low contrast element in
the emulsion. The curve shape is fixed and can not be
modified by exposure.
However, it is possible to dodge and burn using VC
filters to obtain different contrast values in different
parts of the image. This is done by masking off the areas of
the image that are to be printed with different contrast
values and printing them in separately using the appropriate
filter. This is a lot of work but can get very much improved
prints where the range of density in the negative is beyond
the capacity of the paper. It gives an additional control
over normal dodging and burning, which contolls only
exposure.


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

Richard, I hate to disagree with someone as knowledgeable as you, but
I've been doing split filter printing with VC papers for many years and
wouldn't go back to single filter printing for anything.

My practice is to give one exposure at full magenta (I use a colorhead)
and one at full yellow. The number of seconds for each varies with the
paper and degree of enlargement.

The differences in this and in single exposure printing with a mixture
of magenta and yellow or a single contrast filter is subtle but very
real. There is a visible and distinct improvement in local contrast.
The tones take on a glow and "sing" more than they do with a single
exposure. It also makes printing easier--less burning and dodging,
though I do both when necessary, sometimes with both colors if I'm
increasing or decreasing density, or sometimes only with one or the
other if I'm raising or lowering contrast in a particular area of the print.

Larry

Richard Knoppow wrote:

"foto phred"
wrote in message
...


I used to have an article from Zone VI Studios about split
filter paper developing. I moved, and can't find the
directions. Anybody have some help on this please?


--
foto phred

------------------------------------------------------------------------
View this thread:
http://www.photographytalk.net/viewtopic-171060.html

Send from http://www.photographytalk.net



I think you are asking about a method that is supposed
to change the gray scale of the paper. It doesn't work and
is based on a misunderstanding of how variable contrast
papers work.
One can get intermediate grades of contrast by printing
part of the time through a high contrast filter and a low
contrast filter but the results will be no diffent than
gotten with a single filter of the correct grade. There will
be no change in the relative contrast of shadow and
highlight areas. The contrast of vc paper is determined by
the relative exposure of a high and low contrast element in
the emulsion. The curve shape is fixed and can not be
modified by exposure.
However, it is possible to dodge and burn using VC
filters to obtain different contrast values in different
parts of the image. This is done by masking off the areas of
the image that are to be printed with different contrast
values and printing them in separately using the appropriate
filter. This is a lot of work but can get very much improved
prints where the range of density in the negative is beyond
the capacity of the paper. It gives an additional control
over normal dodging and burning, which contolls only
exposure.

They are definitely different! You do wind up with different response
curve - by reason of the different exposure times at the two grades, if
nothing else.

I use split printing when I want the tonality of a lower grade, but the
blacks just aren't there. Often a problem with underexposed
negatives.

First, do a test strip on the shadows with a grade 5. Pick the interval
just before the deep shadows become true black. (Grade 5 Exposure)

Then expose a strip on grade 5 at the Grade 5 Exposure. Then switch to
a grade 0 or 00 filter and (on the same strip) do a test as per normal.
Pick the exposure that which shows the detail in the highlights (Grade
0 Exposure).

Then do you test print - first with the grade 5 filer at the Grade 5
Exposure, then with grade 0 (or 00) at the Grade 0 Exposure. Hold the
filters under the enlarger lens (instead of placing them in the drawer)
to avoid any enlarger movement.

You may have to then tweak the Grade 5 Exposure and Grade 0 Exposure.
If the shadows are blocked up, back off a little on the Grade 5
Exposure. If the highlights aren't there quite, increase the Grade 0
Exposure.

The Grade 0 exposure time might be quite short.

Split printing doesn't work for everything, but is very useful for many
underexposed negatives with weak blacks - especially twilight and night
shots. Other alternatives to split printing include dodging and
burning (of course); simply printing on a high grade (which gives you
separation of close tones & perhaps burning on a low grade to give
tonality to areas of the print) and flashing to give detail to
highlights.

Cheers
Gareth

Richard is absolutely right. I have verified it emirically. Split-grade
printing is a myth.

The crystals don't care whether in what order they are exposed. The
contrast obtainable by simultaneous or successive exposure is exactly
the same.

LR Kalajainen wrote:
Richard, I hate to disagree with someone as knowledgeable as you, but
I've been doing split filter printing with VC papers for many years and
wouldn't go back to single filter printing for anything.

My practice is to give one exposure at full magenta (I use a colorhead)
and one at full yellow. The number of seconds for each varies with the
paper and degree of enlargement.

You can get exactly the same effect by ONE exposure.


The differences in this and in single exposure printing with a mixture
of magenta and yellow or a single contrast filter is subtle but very
real.

No, it's not. You may be seeing some difference in contrast because you
have not matched the two exposures properly.

There is a visible and distinct improvement in local contrast.
The tones take on a glow and "sing" more than they do with a single
exposure. It also makes printing easier--less burning and dodging,
though I do both when necessary, sometimes with both colors if I'm
increasing or decreasing density, or sometimes only with one or the
other if I'm raising or lowering contrast in a particular area of the print.

Larry

Richard Knoppow wrote:

"foto phred"
wrote in message
...


I used to have an article from Zone VI Studios about split
filter paper developing. I moved, and can't find the
directions. Anybody have some help on this please?


--
foto phred

------------------------------------------------------------------------
View this thread:
http://www.photographytalk.net/viewtopic-171060.html

Send from http://www.photographytalk.net



I think you are asking about a method that is supposed
to change the gray scale of the paper. It doesn't work and
is based on a misunderstanding of how variable contrast
papers work.
One can get intermediate grades of contrast by printing
part of the time through a high contrast filter and a low
contrast filter but the results will be no diffent than
gotten with a single filter of the correct grade. There will
be no change in the relative contrast of shadow and
highlight areas. The contrast of vc paper is determined by
the relative exposure of a high and low contrast element in
the emulsion. The curve shape is fixed and can not be
modified by exposure.
However, it is possible to dodge and burn using VC
filters to obtain different contrast values in different
parts of the image. This is done by masking off the areas of
the image that are to be printed with different contrast
values and printing them in separately using the appropriate
filter. This is a lot of work but can get very much improved
prints where the range of density in the negative is beyond
the capacity of the paper. It gives an additional control
over normal dodging and burning, which contolls only
exposure.

I follow the same testing pattern as you suggest, but dialing in the
filtration on my colorhead. By the way, despite turning the dials
between exposures, I've never experienced any movement of the head that
messes up the second exposure. I think it's not a problem using the
filter drawer, so long as you let the enlarger come back to rest after
inserting it.

I use this method exclusively for all negs.

Larry

Gareth wrote:

They are definitely different! You do wind up with different response
curve - by reason of the different exposure times at the two grades, if
nothing else.

I use split printing when I want the tonality of a lower grade, but the
blacks just aren't there. Often a problem with underexposed
negatives.

First, do a test strip on the shadows with a grade 5. Pick the interval
just before the deep shadows become true black. (Grade 5 Exposure)

Then expose a strip on grade 5 at the Grade 5 Exposure. Then switch to
a grade 0 or 00 filter and (on the same strip) do a test as per normal.
Pick the exposure that which shows the detail in the highlights (Grade
0 Exposure).

Then do you test print - first with the grade 5 filer at the Grade 5
Exposure, then with grade 0 (or 00) at the Grade 0 Exposure. Hold the
filters under the enlarger lens (instead of placing them in the drawer)
to avoid any enlarger movement.

You may have to then tweak the Grade 5 Exposure and Grade 0 Exposure.
If the shadows are blocked up, back off a little on the Grade 5
Exposure. If the highlights aren't there quite, increase the Grade 0
Exposure.

The Grade 0 exposure time might be quite short.

Split printing doesn't work for everything, but is very useful for many
underexposed negatives with weak blacks - especially twilight and night
shots. Other alternatives to split printing include dodging and
burning (of course); simply printing on a high grade (which gives you
separation of close tones & perhaps burning on a low grade to give
tonality to areas of the print) and flashing to give detail to
highlights.

Cheers
Gareth

"Richard Knoppow" wrote
"foto phred"
split filter paper [exposure] ... help ... please?

One can get intermediate grades of contrast by printing
part of the time through a high contrast filter and a low
contrast filter but the results will be no different than
gotten with a single filter of the correct grade.

I will second this. Identical results are produced by
split filtering and filtering with one filter.

However - split filtering does allow intermediate contrast
grades. The contrast grades with VC printing filters are
not evenly spaced. The spacing gets worse when using
different filter/paper combinations such as Kodak filters
with Ilford papers.

When it comes to dodging and burning split filtering with
two gel filters or a manual color head is a real PITA.

Split filtering is easier with computerized multi-lamp heads
that vary the timing of the two tubes/lamps and with
automatic filterwheel systems such as the Heiland Split
Grade.

A continuously variable color or VC head should obviate any
advantage to split filtering as all intermediate contrasts
are available. The problem is translating the traditional
two test strip high-contrast/low contrast results into
filterwheel settings.

--
Nicholas O. Lindan, Cleveland, Ohio
Consulting Engineer: Electronics; Informatics; Photonics.
To reply, remove spaces: n o lindan at ix . netcom . com
Fstop timer - http://www.nolindan.com/da/fstop/index.htm

Yes, it's an interesting issue.

I use filters. With the type of negatives I use split printing for
(i.e badly exposed ones), I use long grade 5 exposures and very short
grade 0/00 exposures.

I suppose that, in strict theory, this translates into somewhere
between grade 4.5 and 5 (essentially, magenta with a splash of yellow).


But the splash of yellow is a very precise thing.

Theoretically, that could be reproduced with a single exposure with a
colour head - but you'd have to test to get the yellow right. So, you'd
probably start with a magenta equivalent to a grade 5 - get the
exposure right for the blacks - one test strip. Then you would need
to start adding yellow until the highlights / mid tones were ok (one
test strip at least, perhaps more)

Meaning, I suspect you'd be in the same place - but with at least 2
tests, perhaps more.

Any thoughts?

Regards
Gareth