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Metering for B/W Films



 
 
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  #1  
Old March 5th 12, 11:01 PM
Darkroom User Darkroom User is offline
Junior Member
 
First recorded activity by PhotoBanter: Aug 2010
Posts: 27
Default Metering for B/W Films

There are many discussions on the internet for using lightmeters, either reflective or incident. Much of it for digital or color reversal films.

When it comes down to B/W films, methods such as the zone system or BTZS are mentioned.

How do the visitors here like to use their lightmeters for exposing B/W films for enlarging or contacts in the wet darkroom?
  #2  
Old March 6th 12, 03:47 AM posted to rec.photo.darkroom
Francis A. Miniter[_2_]
external usenet poster
 
Posts: 9
Default Metering for B/W Films

On 3/5/2012 17:01 PM, Darkroom User wrote:
There are many discussions on the internet for using lightmeters, either
reflective or incident. Much of it for digital or color reversal films.

When it comes down to B/W films, methods such as the zone system or BTZS
are mentioned.

How do the visitors here like to use their lightmeters for exposing B/W
films for enlarging or contacts in the wet darkroom?


I don't. I have an old spot-type print analyzer that I use
to get dynamic range and then time settings. It would seem
to me that a light meter, unless it is a spot meter, is not
going to be all that useful in the darkroom.

--
Francis A. Miniter

Mesure is Medicine þauh þou muche ȝeor[n]e.
Al nis not good to þe gost þat þe bodi lykeþ,
Ne lyflode to þe licam þat leof is to þe soule.

William Langland, The Vision of Piers Plowman
Passus I, lines 33 - 35
  #3  
Old March 6th 12, 07:34 AM posted to rec.photo.darkroom
Geoffrey S. Mendelson
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Posts: 450
Default Metering for B/W Films

Francis A. Miniter wrote:

I don't. I have an old spot-type print analyzer that I use
to get dynamic range and then time settings. It would seem
to me that a light meter, unless it is a spot meter, is not
going to be all that useful in the darkroom.


Another approach which worked well in the past when no one worried about being
able to buy another box of paper or a bottle of developer, was a test print.

Often I would tear a piece of paper into quarters, or use a sheet of paper
that had been crumpled, bent, torn, etc.

I would pick the area of the print I thought was most important and print
that. Once it was in the fixer, I'd turn a light on and look.

I had a very bright light over the sink, so I could judge a print as I was
washing it.

The zone system and others like it are camera systems to produce a negative
that has a tonal range and print exposure like every other negative you produce,
making printing easier.

It is interesting to see the prints made by and for various photographers over
the years from the same negative, for example Ansel Adams.

Geoff.
--
Geoffrey S. Mendelson, N3OWJ/4X1GM
My high blood pressure medicine reduces my midichlorian count. :-(


  #4  
Old March 6th 12, 06:07 PM posted to rec.photo.darkroom
Dennis Boone
external usenet poster
 
Posts: 18
Default Metering for B/W Films

When it comes down to B/W films, methods such as the zone system or BTZS
are mentioned.


How do the visitors here like to use their lightmeters for exposing B/W
films for enlarging or contacts in the wet darkroom?


As a coarse approximation, I meter the darkest shadows where I want
some detail, meter the bright spots (avoiding specular reflections),
split the difference. If the difference is too broad, you'll exceed
the range of the film (unless you have the ability to adjust the
processing per frame, i.e. sheet film). If the whole scene is very
dim, you may end up "promoting" it all to appear brighter than it was.
Etc.

Bottom line, the "correct" exposure is the one that gives you the
result you wanted.

It's worth reading the Ansel Adams and Phil Davis books, even if you
don't intend to do the whole calibrated process thing. There's a
fair amount of useful thumb rule stuff in there, and they can help you
cement the idea of shifting things up and down the scale to get what
you want.

De
  #5  
Old March 6th 12, 06:32 PM
Darkroom User Darkroom User is offline
Junior Member
 
First recorded activity by PhotoBanter: Aug 2010
Posts: 27
Default

Quote:
Originally Posted by Francis A. Miniter[_2_] View Post
On 3/5/2012 17:01 PM, Darkroom User wrote:
There are many discussions on the internet for using lightmeters, either
reflective or incident. Much of it for digital or color reversal films.

When it comes down to B/W films, methods such as the zone system or BTZS
are mentioned.

How do the visitors here like to use their lightmeters for exposing B/W
films for enlarging or contacts in the wet darkroom?


I don't. I have an old spot-type print analyzer that I use
to get dynamic range and then time settings. It would seem
to me that a light meter, unless it is a spot meter, is not
going to be all that useful in the darkroom.

--
Francis A. Miniter
I should have made my post more clear. I meant exposing the films in camera.
I mentioned the wet darkroom, because that is how I make my prints.
  #6  
Old March 7th 12, 03:47 AM posted to rec.photo.darkroom
Francis A. Miniter[_2_]
external usenet poster
 
Posts: 9
Default Metering for B/W Films

On 3/6/2012 12:32 PM, Darkroom User wrote:
'Francis A. Miniter[_2_ Wrote:
;945476']On 3/5/2012 17:01 PM, Darkroom User wrote:-
There are many discussions on the internet for using lightmeters,
either
reflective or incident. Much of it for digital or color reversal
films.

When it comes down to B/W films, methods such as the zone system or
BTZS
are mentioned.

How do the visitors here like to use their lightmeters for exposing
B/W
films for enlarging or contacts in the wet darkroom?
-

I don't. I have an old spot-type print analyzer that I use
to get dynamic range and then time settings. It would seem
to me that a light meter, unless it is a spot meter, is not
going to be all that useful in the darkroom.

--
Francis A. Miniter

I should have made my post more clear. I meant exposing the films in
camera.
I mentioned the wet darkroom, because that is how I make my prints.



Ah. When shooting, I prefer a spot meter, or, if I am using
a camera with multiple function metering, I almost always
choose the spot option. I prefer to do my own "weighting"
of the scene, especially since I want to make sure that the
object of the scene, whether on center or off, is properly
metered, whatever else about the rest of the scene. I don't
overtly use the zone system, but I do try to compensate for
overly wide or overly narrow dynamic light ranges.

By the way, I rarely use color reversal films. Most of my
shooting is B&W, with about a third to 40% color negative
film.


--
Francis A. Miniter

Mesure is Medicine þauh þou muche ȝeor[n]e.
Al nis not good to þe gost þat þe bodi lykeþ,
Ne lyflode to þe licam þat leof is to þe soule.

William Langland, The Vision of Piers Plowman
Passus I, lines 33 - 35
  #7  
Old March 8th 12, 03:54 PM posted to rec.photo.darkroom
Jean-David Beyer
external usenet poster
 
Posts: 245
Default Metering for B/W Films

Darkroom User wrote:
There are many discussions on the internet for using lightmeters,
either reflective or incident. Much of it for digital or color
reversal films.

When it comes down to B/W films, methods such as the zone system or
BTZS are mentioned.

How do the visitors here like to use their lightmeters for exposing
B/W films for enlarging or contacts in the wet darkroom?

I have two lightmeters. One is a Pentax digital spot meter modified by
Zone VI. The other is a Luna-Pro-F that is either a reflective meter or
an incident light meter, depending on whether the white dome is over the
cell or not. It also works as a flash meter.

Normally, I shoot outdoors and use the spot meter, using the Zone
System. I carry the Luna-Pro as well as a backup. This saved me once
when I forgot to change the battery in the Zone VI, and it went dead on me.

When shooting with electronic flash, I use the Luna-Pro-F in flash mode,
usually incident readings.

It is important to know what the meters are doing, especially if you
have more than one, or you will drive yourself crazy. They will seldom
read the same, and the differences are more than just the different
sensitivity to the illumination. That could be simply calibrated for.
They are also different to different colors, and unless you make a very
careful test, this is impossible to calibrate for. What I did (once: it
is a pain to do it multiple times), was wet up an 18% gray card and
illuminated it from a blue sky. The illumination was not changing during
the test. The gray card was the same color from test-to-test, and was as
good a standard as any. Especially since I normally shoot in black and
white. For that I could get a bunch of meters to read the same. One
camera meter had a CdS cell, and the rest were silicon, but with
different color response curves. The Zone VI is allegedly calibrated so
the film sees what the eye sees, or something like that. But that would
depend on what kind of film was used, and I suppose Fred Picker used
either Tri-X 4164 or maybe Plus-X 4147. Since I shoot TMax, it will have
a different curve. I doubt this matters very much because the saturation
of colors around here is not very great.

At first I was surprised that the Luna-Pro gave different readings for
incident light and for reflected light from the gray card. This was when
reading incident light with the sun in the sky. I then figured out how
to do the measurement when the meter and the gray card could not see the
sun. Then the meter read the same incident and reflected. Wow! The
subtleties will get you if you have more than one meter.

--
.~. Jean-David Beyer Registered Linux User 85642.
/V\ PGP-Key: 9A2FC99A Registered Machine 241939.
/( )\ Shrewsbury, New Jersey http://counter.li.org
^^-^^ 09:35:01 up 19:16, 4 users, load average: 4.65, 4.74, 4.72
  #8  
Old March 21st 12, 05:35 PM posted to rec.photo.darkroom
Richard Knoppow
external usenet poster
 
Posts: 752
Default Metering for B/W Films


"Jean-David Beyer" wrote in message
...
Darkroom User wrote:
There are many discussions on the internet for using
lightmeters,
either reflective or incident. Much of it for digital or
color
reversal films.

When it comes down to B/W films, methods such as the zone
system or
BTZS are mentioned.

How do the visitors here like to use their lightmeters
for exposing
B/W films for enlarging or contacts in the wet darkroom?

I have two lightmeters. One is a Pentax digital spot meter
modified by
Zone VI. The other is a Luna-Pro-F that is either a
reflective meter or
an incident light meter, depending on whether the white
dome is over the
cell or not. It also works as a flash meter.

Normally, I shoot outdoors and use the spot meter, using
the Zone
System. I carry the Luna-Pro as well as a backup. This
saved me once
when I forgot to change the battery in the Zone VI, and it
went dead on me.

When shooting with electronic flash, I use the Luna-Pro-F
in flash mode,
usually incident readings.

It is important to know what the meters are doing,
especially if you
have more than one, or you will drive yourself crazy. They
will seldom
read the same, and the differences are more than just the
different
sensitivity to the illumination. That could be simply
calibrated for.
They are also different to different colors, and unless
you make a very
careful test, this is impossible to calibrate for. What I
did (once: it
is a pain to do it multiple times), was wet up an 18% gray
card and
illuminated it from a blue sky. The illumination was not
changing during
the test. The gray card was the same color from
test-to-test, and was as
good a standard as any. Especially since I normally shoot
in black and
white. For that I could get a bunch of meters to read the
same. One
camera meter had a CdS cell, and the rest were silicon,
but with
different color response curves. The Zone VI is allegedly
calibrated so
the film sees what the eye sees, or something like that.
But that would
depend on what kind of film was used, and I suppose Fred
Picker used
either Tri-X 4164 or maybe Plus-X 4147. Since I shoot
TMax, it will have
a different curve. I doubt this matters very much because
the saturation
of colors around here is not very great.

At first I was surprised that the Luna-Pro gave different
readings for
incident light and for reflected light from the gray card.
This was when
reading incident light with the sun in the sky. I then
figured out how
to do the measurement when the meter and the gray card
could not see the
sun. Then the meter read the same incident and reflected.
Wow! The
subtleties will get you if you have more than one meter.


I think the key is the same as in electronics and
elsewhere, namely understand what your instruments are
actually measuring.
From the 1920s through the 1950s a long series of
research reports was published by Loyd A. Jones, along with
some others, of Kodak Research Laboratories, on the tone
rendition of film and paper. Much of this was directed
toward black and white but has applications even for color.
One of the results of this research was the speed system
adopted by the ASA in the mid 1940s. Among other things
Jones wanted to find out the _minimum_ exposure that would
result in an _excellent_ print. The idea was that film
produced the sharpest images and least grain with minimal
exposure. Film is better now but this still is true. After
extensive testing on actual scenes and blind testing of
prints from the negatives, Jones found a definite speed
point for minimum exposure but also found that the
overexposure latitude was very great. That is, once the
film gets enough exposure to make a good print further
exposure does not change the tone rendition over a range of
many stops.
The Kodak Speed System adopted by the ASA, and indeed
all subsequent speed systems, assume a fixed gamma or
contrast index for the negatives. The idea is that the scene
brightnesses would be accurately recorded so that print
contrast would be determined by the contast of the paper.
The development of the Zone System essentially reverses this
approach in that it adjusts the contrast of the negative to
fit a fixed contrast printing medium, the idea is to insure
fitting all important scene brightness data on the negative.
Either system works. One reason Ansel Adams promoted the
Zone System is that he had gotten poor negatives for some
important pictures due to under-exposure. While the
latitude of _overexposure_ of most film is very great, the
latitude for _underexposure_ is no more than one stop and
maybe less.
Assuming one has printable negatives made by any
exposure system one encounters another problem: namely the
tone range of paper prints to be illuminated by reflected
light, is far less than either the range of brightness in
the original scene or the range on the negative. However,
the eye still expects to see something like the original
tone range, at least in the mid-tones. If overall contrast
is lowered to present a high-contrast (wide tone range)
scene on the print the result will be seen by the eye to be
grayed out, especially if the scene is something fairly
familiar. The approach that has developed over time is the
compress the highlights and shadows to some degree while
leaving the mid-tones alone. In chemical photograpy this is
done partly by choosing paper with an S shaped charistic, or
the use of masking, or simply manual burning and dodging. No
adjustment of exposure and development will replace this.
The best one can expect of a light meter is that it
will help fit the scene brightness range into the range that
can be recorded on the film.
The main difference between a reflected light meter and
an incident light meter is that the incident meter can not
measure subject brightness range. It _can_ measure lighting
ratio directly, which is often helpful where lighting is
under control. A reflected light meter can measure subject
brightness range. Both types of meters are useful but
again one must understand what they are measuring in terms
of what will be recorded on the film.
I am glad to see a few of us still follow this news
group.


--

--
Richard Knoppow
Los Angeles
WB6KBL



  #9  
Old March 22nd 12, 01:05 PM
Darkroom User Darkroom User is offline
Junior Member
 
First recorded activity by PhotoBanter: Aug 2010
Posts: 27
Default

Quote:
Originally Posted by Richard Knoppow View Post
I think the key is the same as in electronics and
elsewhere, namely understand what your instruments are
actually measuring.

From the 1920s through the 1950s a long series of
research reports was published by Loyd A. Jones, along with
some others, of Kodak Research Laboratories, on the tone
rendition of film and paper. Much of this was directed
toward black and white but has applications even for color.
One of the results of this research was the speed system
adopted by the ASA in the mid 1940s. Among other things
Jones wanted to find out the _minimum_ exposure that would
result in an _excellent_ print. The idea was that film
produced the sharpest images and least grain with minimal
exposure. Film is better now but this still is true. After
extensive testing on actual scenes and blind testing of
prints from the negatives, Jones found a definite speed
point for minimum exposure but also found that the
overexposure latitude was very great. That is, once the
film gets enough exposure to make a good print further
exposure does not change the tone rendition over a range of
many stops.
The Kodak Speed System adopted by the ASA, and indeed
all subsequent speed systems, assume a fixed gamma or
contrast index for the negatives. The idea is that the scene
brightnesses would be accurately recorded so that print
contrast would be determined by the contast of the paper.
The development of the Zone System essentially reverses this
approach in that it adjusts the contrast of the negative to
fit a fixed contrast printing medium, the idea is to insure
fitting all important scene brightness data on the negative.
Either system works. One reason Ansel Adams promoted the
Zone System is that he had gotten poor negatives for some
important pictures due to under-exposure. While the
latitude of _overexposure_ of most film is very great, the
latitude for _underexposure_ is no more than one stop and
maybe less.
Assuming one has printable negatives made by any
exposure system one encounters another problem: namely the
tone range of paper prints to be illuminated by reflected
light, is far less than either the range of brightness in
the original scene or the range on the negative. However,
the eye still expects to see something like the original
tone range, at least in the mid-tones. If overall contrast
is lowered to present a high-contrast (wide tone range)
scene on the print the result will be seen by the eye to be
grayed out, especially if the scene is something fairly
familiar. The approach that has developed over time is the
compress the highlights and shadows to some degree while
leaving the mid-tones alone. In chemical photograpy this is
done partly by choosing paper with an S shaped charistic, or
the use of masking, or simply manual burning and dodging. No
adjustment of exposure and development will replace this.
The best one can expect of a light meter is that it
will help fit the scene brightness range into the range that
can be recorded on the film.
The main difference between a reflected light meter and
an incident light meter is that the incident meter can not
measure subject brightness range. It _can_ measure lighting
ratio directly, which is often helpful where lighting is
under control. A reflected light meter can measure subject
brightness range. Both types of meters are useful but
again one must understand what they are measuring in terms
of what will be recorded on the film.
I am glad to see a few of us still follow this news
group.


--

--
Richard Knoppow
Los Angeles
WB6KBL
Thanks Richard, but I am still not sure whether to rely on Incident or reflective measurements. How do you use your lightmeter for outdoor photography?
  #10  
Old April 12th 12, 04:37 AM posted to rec.photo.darkroom
Richard Knoppow
external usenet poster
 
Posts: 752
Default Metering for B/W Films


"Darkroom User"
wrote in message
news

hanks Richard, but I am still not
sure whether to rely on Incident or

reflective measurements. How do you use your lightmeter
for outdoor
photography?




--
Darkroom User


Personally, I use a combination meter usually an old
Gossen or a Sekonik Studio meter similar to the old Norwood.
These give a choice of incident or reflected readings. I
can write a long treatice on the difference but I've also
shot a lot of color slides using the TTL meter on a Nikon F
and very few were badly exposed. This is, of course, a
reflected light meter. I think you can get good results
with either provided you understand what its measuring.
In principle, the incident meter should give you a more
exact rendition of what the scene looks like but that may
not be what you want. It can not measure _subject_
brightness and contrast where the reflected light meter can.
OTOH, the reflected light meter will need some help from you
in deciding how bright the objects in the picture are to be
in the print.
I also have some questions about the actual utility of
the hemispherical light integrator found on many meters.
Supposing one is photographing a back-lighted scene; does
one want the exposure to be for the relatively shadowy areas
for the very bright highlights? If the meter is used as
directed, that is held in the scene and pointed toward the
camera, the sensor will not see the light coming from behind
and result in a much greater exposure that will wash out the
backlighted highlights. If its pointed at the source of
light it will expose the highlights correctly but blank out
the shadows. You have to decide what you want to show up on
the film.
What can be difficult is that in life the eye is making
constant rapid adjustments for light level which can fool us
about just how great they are.



--
Richard Knoppow
Los Angeles
WB6KBL



 




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