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Darkroom Automation Precision Enlarging Meter: New Product Announcement



 
 
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  #1  
Old August 25th 06, 04:22 PM posted to rec.photo.darkroom
Nicholas O. Lindan
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Posts: 1,227
Default Darkroom Automation Precision Enlarging Meter: New Product Announcement

Hot off the press:

The Darkroom Automation Precision Enlarging Meter

Darkroom Automation's enlarging meter provides 0.01 stop resolution over
a ten stop range, making it easy to hit highlights and shadows on the first
print. Its exclusive Delta mode quickly determines paper grade, burn,
and dodge exposures. Working as a system with the Darkroom Automation
F-Stop timer, it can also be used with any analog or digital timer.
Absolute factory calibration means all meters read the same -- great
for large commercial and university darkrooms [or sharing data on
the internet].

$79 + s/h.

http://www.nolindan.com/da/index.htm

--
Nicholas O. Lindan, Cleveland, Ohio
Darkroom Automation


  #2  
Old August 25th 06, 05:05 PM posted to rec.photo.darkroom
j
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Posts: 77
Default Darkroom Automation Precision Enlarging Meter: New Product Announcement

"Nicholas O. Lindan" wrote in message
nk.net...
Hot off the press:

The Darkroom Automation Precision Enlarging Meter


Nicholas: What is Delta Mode, please? Seriously, I don't understand.

Thanks,


  #3  
Old August 27th 06, 10:29 AM posted to rec.photo.darkroom
[email protected]
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Posts: 137
Default Darkroom Automation Precision Enlarging Meter: New Product Announcement


Nicholas O. Lindan wrote:
Hot off the press:

The Darkroom Automation Precision Enlarging Meter


I wonder if it might make a good easel densitometer?
I've calibrated my EM-10 against a step wedge for use as
one. I figure about .05 resolution. Not bad for $24.50. Dan

  #4  
Old August 28th 06, 02:34 PM posted to rec.photo.darkroom
Nicholas O. Lindan
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Posts: 1,227
Default Darkroom Automation Precision Enlarging Meter: New Product Announcement

"j" wrote
"Nicholas O. Lindan" wrote.
New product announcement:
The Darkroom Automation Precision Enlarging Meter
http://www.nolindan.com/da/index.htm

Nicholas: What is Delta Mode, please? Seriously, I don't understand.


Thanks, I guess I need to expand the web site a bit, (cough).

== Controls ==

The meter has two momentary pushbuttons on the top surface.

o The left button turns the meter on and off: Tapping it turns
the meter on; Holding it down for a second turns the meter off.

o The right button toggles the meter between normal mode and
delta mode and when held down takes a reference reading for
displaying the difference between two spots.

The meter turns itself off if no button is pressed in 5 minutes.

== Normal Mode ==

The meter 'wakes up' in normal mode and works like a digital spotmeter where
the spot measured a spot on the enlarging meter. The number displayed shows
the quantity of light in 1/100's of a stop. The 1/100's display eliminates
rounding errors when several measurements are used to determine paper grade,
base exposure and burn and dodge exposures.

Normal Mode measurements determine the base exposure by measuring the
shadows [low key], mid-tones [portraiture] or highlights [high key].

When used with the Darkroom Automation F-Stop timer a very simple
relationship appears:

‘Paper Speed’ = Meter Reading + Timer Setting

where Paper Speed is a constant. Given a paper and desired tone there is a
number that is a product of time and light intensity that will produce that
tone. Paper Speed is easily determined by making a test strip with no
negative and adding the time of the strip showing the correct tone to the
number shown on the Enlarging Meter. As we are working in stops for both
time and light intensity simple addition is all that is needed for all
exposure determinations.

When Paper Speed is known the F-Stop timer setting is simply:

Timer Setting = Paper Speed - Meter Reading.

Any timer can be used with the meter: F-Stop charts and a spiral F-Stop
scale for clock-faced timers come with the meter. Using charts and an
ordinary timer is the most common method for ‘F-Stop printing,’
an F-Stop timer makes the work easier and more pleasant.

== Delta Mode ==



The right button toggles the meter between Delta Mode and Normal Mode. Delta
mode shows the light intensity difference between any two spots on the
image. The meter is placed under the part of the image to be used as the
‘reference’ or ‘base’ and the delta button is held down for a second. The
meter display changes to 0.00 and the meter now shows the difference in
light intensity in stops. An ‘r’ or ‘-‘ shows in the display to indicate a
delta reading. The reference reading is remembered when the meter is turned
off.

Use Delta Mode to:

o Determine paper grade by measuring the intensity
difference (‘delta’) between the shadows and the
highlights or between the two most important tones
in the image.

o Make fine corrections after making a test print by
measuring the difference between two spots in the
image: a spot where the print has the tone you want
and a spot that has the tone you want to correct.
The delta reading is the adjustment to the F-Stop
timer/print time.

o Determine dodging and burning requirements. Several
methods are possible but an example is: Measure the
foreground highlights and the highlights in the
clouds - the delta reading is the amount to burn
in the sky.

== Meter Calibration ==

The meter is calibrated so that full scale, 9.99, is approximately the
amount of light needed to achieve full black in two seconds on Ilford MGIV.
The other end of the scale, 0.00, is the amount of light needed to achieve
full black in 2000 seconds – 33 minutes of exposure.

All meters read the same under the same conditions. This allows data to be
shared among photographers.

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


  #5  
Old August 28th 06, 03:13 PM posted to rec.photo.darkroom
Nicholas O. Lindan
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Posts: 1,227
Default Darkroom Automation Precision Enlarging Meter: New Product Announcement

wrote in message
oups.com...

Nicholas O. Lindan wrote:
The Darkroom Automation Precision Enlarging Meter
http://www.nolindan.com/da/index.htm


I wonder if it might make a good easel densitometer?


A very good one, though an 'easel densitometer' won't
read the same as an ANSI/ISO densitometer. On the other
hand the 'density' it reads is the density that matters.
Readings are very stable, all meters are calibrated,
linearity is excellent. And it has a delta mode for
reading intensity differences so if used as a
densitometer it is easy to zero out film base+fog and
enlarger height/f-stop.

I've calibrated my EM-10 against a step wedge for use as
one.


And every EM-10 is different. A volume control potentiometer
is used for the logarithm conversion: the graph of OD/Meter reading
is not pretty.

http://www.nolindan.com/em10graph001.jpg

I figure about .05 resolution.


..05 OD - .15 stops

The resolution depends on the density as the readout
isn't linear. And you have to turn the lights on
to read the dial.

Not bad for $24.50. Dan



For it's original purpose - to match light intensity
when making Ilfochromes it is a great little gadget.
As a densitometer, it can be done, and it is cheap,
but it was never meant to be one.


  #6  
Old September 5th 06, 10:42 AM posted to rec.photo.darkroom
[email protected]
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Posts: 137
Default Darkroom Automation Precision Enlarging Meter: New Product Announcement

Nicholas O. Lindan wrote:

wrote

I've calibrated my EM-10 against a step wedge for use as
one.


And every EM-10 is different. A volume control potentiometer
is used for the logarithm conversion: the graph of OD/Meter reading
is not pretty.

http://www.nolindan.com/em10graph001.jpg

Not pretty. That's true. I've calibrated mine as with an
8x10 enlargement using the projection of the step wedge.
I calibrated for 5 f stops; f8 - f32. At f8 the more dense steps
and at f32 the less dense steps can be measured at
a greater resolution.

I figure about .05 resolution.


.05 OD - .15 stops

Exactly 1/6 stop.

And you have to turn the lights on to read the dial.

Even at f32 I can read the dial.

Not bad for $24.50.


For it's original purpose - to match light intensity
when making Ilfochromes it is a great little gadget.
As a densitometer, it can be done, and it is cheap,
but it was never meant to be one.


Ilfochromes? Any print. Dan

  #7  
Old September 5th 06, 03:16 PM posted to rec.photo.darkroom
Nicholas O. Lindan
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Posts: 1,227
Default Darkroom Automation Precision Enlarging Meter: New Product Announcement

[Comparison of Ilford EM-10
http://www.bhphotovideo.com/bnh/cont...list&sku=24631

With the Darkroom Automation Precision Enlarging Meter:

http://www.nolindan.com/da/em/em1003main.htm

wrote
Nicholas O. Lindan [from Darkroom Automation] wrote:
And every EM-10 is different. A volume control potentiometer
is used for the logarithm conversion: the graph of OD/Meter reading
is not pretty.
http://www.nolindan.com/em10graph001.jpg

Not pretty. That's true. I've calibrated mine.
Have to turn the lights on to read the dial

Even at f32 I can read the dial.

I can't.

For it's original purpose - to match light intensity
when making Ilfochromes it is a great little gadget.


Ilfochromes? Any print. Dan


Designed for Ilfochromes / Cibachromes ... color balance
shifts if the exposure time changes; the goal is to make
all prints at the same exposure time. The
lens aperture is changed to keep the light on the
easel constant. The 'calibration' value on the back
is the dial setting for an 18% gray at 20 seconds
[or thereabouts] with Ilfochrome.

They _can_ indeed be used for any print but they were
not designed for general purpose measurement of light.
And that is why the ugly response curves weren't a
design issue in the product: Ugly works; Ugly is
cheap; Ugly is good.

Some use the meter as they were intended - to keep exposure
time constant - when printing black and white. For a 2 stop
range, say 5.6-8-11 for a 50/2.8 El-Whatsitogon this works
fine. For a four stop range, 5.6-8-11-16-22, it's ok:
optical performance suffers a bit at f16/22 but print size
is probably 3.5x5 and so the issue is moot.

Early enlarging exposure meters had a piece of
paper with an oil spot on it and a small light bulb
behind the paper. When the light from the enlarger
equaled the light from the light bulb the oil spot
'disappeared. Same technology in the year
1702 with parchment and a candle: hence the use of
a 'foot-candle' as the standard unit of light, the
candle was placed one foot behind the oil-spotted
parchment.

Back to the EM10:

For general purpose use the ugly calibration curve means
you have to calibrate each EM-10 with a step tablet and
densitometer.

Caveats with the EM-10:

o At low light levels it can take 5 seconds for
the meter to settle down due to the memory of
the CdS cell.

o The calibration curve drifts with temperature
and humidity so the meter should be checked if
darkroom conditions are other than normal.

o The calibration curve drifts with time? I have
one that behaves very differently than it did a
year ago. This only happened in one sample and
the problem may not be in the meter but in the
measurement or record keeping.

o The calibration drifts with use: the meter uses a
plain-ole radio volume control. Expect the same
problems with the meter as you have with some
radios: you just _can't_ get the volume right
anymore. If the meter is always futzed with at
the same dial setting the carbon in the volume control
at that location wears out.

Ilford's instructions as printed in the B&H web site
have the meter recalibrated every printing session:
record what the meter reads that day with a
standard negative/magnification/f-stop . They are
a lot more stable than that, but calibration should
be checked periodically.

* * *

The 'no enlarging meter/EM-10/DA meter' debate is an
extension of the 'Throw Down Your Exposure Meter, Fools.'
threads that pop up:

Some [well, at least one] think 'Sunny-16' is the be-all
of exposure. For others, what the camera picks when
set to A or P is all that's needed. And some think if you
really want to do it right a precision spot-meter is
the way to go.

Pays your money - makes your choice. A good exposure
meter isn't needed to take a fine photograph/make a fine
print but it does make the success rate higher, extend
the envelope of what can be achieved and lessens the time
and waste.

One cheap meter and a box of paper in the waste basket
costs the same as a good meter without using all that
paper on test/oops/just a bit more|less prints.

With a good meter [and a bit of practice] you don't get
close, you nail it. No sights, plain sight or a scope:
which do you want on your rifle?

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


  #8  
Old September 5th 06, 04:14 PM posted to rec.photo.darkroom
Lloyd Erlick
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Posts: 214
Default Darkroom Automation Precision Enlarging Meter: New Product Announcement

On Tue, 05 Sep 2006 14:16:45 GMT, ...

carbon in the volume control wears out.
--Nicholas O. Lindan




September 5, 2006, from Lloyd Erlick,

This explains everything!

I'm indebted to you for this! The shock of
recognition, no batteries needed ...

regards,
--le

 




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