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Stupid Darkroom Idea



 
 
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  #1  
Old November 12th 08, 02:18 AM posted to rec.photo.darkroom
John J
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Posts: 110
Default Stupid Darkroom Idea

The scanner thread pinged my imagination. Didn't come up with a response
but reminded me...

8x10 enlarger light source - what about an intense tube light moved by a
scanner (stepper) motor close to the negative? It would make a low
profile head, be cool (temp), is programmable (motion rate), and just
fill my weeks with an excuse not to shoot!

Gosh, what else? Oh, I got a ping response (60000ms) and it said, "Ya
broke yer metronome, so how about putting that VAX 11/730 to use in
there? It's got a bad disc that has just about the right tick!

  #2  
Old November 12th 08, 03:42 AM posted to rec.photo.darkroom
David Nebenzahl
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Default Stupid Darkroom Idea

On 11/11/2008 5:18 PM John J spake thus:

The scanner thread pinged my imagination. Didn't come up with a response
but reminded me...

8x10 enlarger light source - what about an intense tube light moved by a
scanner (stepper) motor close to the negative? It would make a low
profile head, be cool (temp), is programmable (motion rate), and just
fill my weeks with an excuse not to shoot!


Lemme see if I understand this: this would be a light source that would
be "scanned" across the negative (I assume in just one axis, not an x/y
scan) while the exposure is being made? So the stepper would have to
complete its run in the time of the exposure? Hmmmmm ... verrrrry
eenteresting.


--
Washing one's hands of the conflict between the powerful and the
powerless means to side with the powerful, not to be neutral.

- Paulo Freire
  #3  
Old November 12th 08, 04:00 AM posted to rec.photo.darkroom
John J
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Posts: 110
Default Stupid Darkroom Idea

David Nebenzahl wrote:
On 11/11/2008 5:18 PM John J spake thus:

The scanner thread pinged my imagination. Didn't come up with a
response but reminded me...

8x10 enlarger light source - what about an intense tube light moved by
a scanner (stepper) motor close to the negative? It would make a low
profile head, be cool (temp), is programmable (motion rate), and just
fill my weeks with an excuse not to shoot!


Lemme see if I understand this: this would be a light source that would
be "scanned" across the negative (I assume in just one axis, not an x/y
scan) while the exposure is being made? So the stepper would have to
complete its run in the time of the exposure? Hmmmmm ... verrrrry
eenteresting.


If the idea came to my mind, then it is certain that someone smarter has
already considered, then discarded it. But I'll sleep on it.

  #4  
Old November 12th 08, 05:04 AM posted to rec.photo.darkroom
Jean-David Beyer
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Posts: 247
Default Stupid Darkroom Idea

John J wrote:
David Nebenzahl wrote:
On 11/11/2008 5:18 PM John J spake thus:

The scanner thread pinged my imagination. Didn't come up with a
response but reminded me...

8x10 enlarger light source - what about an intense tube light moved by
a scanner (stepper) motor close to the negative? It would make a low
profile head, be cool (temp), is programmable (motion rate), and just
fill my weeks with an excuse not to shoot!

Lemme see if I understand this: this would be a light source that would
be "scanned" across the negative (I assume in just one axis, not an x/y
scan) while the exposure is being made? So the stepper would have to
complete its run in the time of the exposure? Hmmmmm ... verrrrry
eenteresting.


If the idea came to my mind, then it is certain that someone smarter has
already considered, then discarded it. But I'll sleep on it.

It has been done in various ways for a very long time.

In 1927 or thereabouts, my grandfather made one of the first television
systems at Bell Labs. They did not have image orthocon tubes, or even
iconoscopes in those days. He invented a way to make sensitive photocell
tubes. They placed these around the studio (which was illuminated with
subdued lighting. They had a carbon arc light that went through a spinning
Nipkow disk (a disk with a spiral of holes in it) and an optical system so
the beam of light scanned the scene and the photocells picked up the light.

This actually worked, and was a lot cooler than if the entire scene were
illuminated to the level the arc light put out.

This link shows a little of how it worked, but important details seem to be
missing:

http://www.earlytelevision.org/bell_labs.html

This link shows my grandfather holding one of the photocells he made:

http://movingimage.us/site/calendar/...7/1987_dec.pdf

This one is a bit easier to read:

http://www.corp.att.com/history/television/ives.html
http://www.corp.att.com/history/tele...witworked.html

Since they did not have CRTs yet that would show to a crowd, they made a
monitor that was a huge neon sign tube that went back and forth to make up
the image area, with lots of electrodes that could control the brightness of
each picture element. There was a big synchronous motor (had to be
synchronized with that in the "camera") to select which picture element
would be illuminated.

We have come a long way in less than 100 years.

Later, devices called flying spot scanners were made, that generally used a
CRT as the light source. But when my grandfather started out, no one had put
a phosphor at the front of a crt before, and they generally deflected the
beam only along one axis.


--
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  #5  
Old November 12th 08, 05:15 AM posted to rec.photo.darkroom
John J
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Posts: 110
Default Stupid Darkroom Idea

Jean-David Beyer wrote:

In 1927 or thereabouts, my grandfather made one of the first television
systems at Bell Labs. They did not have image orthocon tubes, or even
iconoscopes in those days. He invented a way to make sensitive photocell
tubes. They placed these around the studio (which was illuminated with
subdued lighting. They had a carbon arc light that went through a
spinning Nipkow disk (a disk with a spiral of holes in it) and an
optical system so the beam of light scanned the scene and the photocells
picked up the light.

This actually worked, and was a lot cooler than if the entire scene were
illuminated to the level the arc light put out.


And I'll bet was awesome to be there! That's a great example of
inventive thinking.

[.. snip more great stuff ..]

Later, devices called flying spot scanners were made, that generally
used a CRT as the light source. But when my grandfather started out, no
one had put a phosphor at the front of a crt before, and they generally
deflected the beam only along one axis.


My small story: My Uncle, Domina Jalbert worked for fifty years on a
wind lift sail/kite problem - to make one effective without any rigid
stays. At 60-something years old it came to him all at once. He went
into his shop, sewed up a 6' prototype, took it outside and said it
nearly lifted him off his feet. "I knew I had it then". It is known as
the Jalbert Parafoil - the first parasail. Patented 1964.

Here it to our inventive ancestors!



  #6  
Old November 12th 08, 07:10 PM posted to rec.photo.darkroom
Ken Hart1
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Posts: 79
Default Stupid Darkroom Idea


"John J" wrote in message
m...
The scanner thread pinged my imagination. Didn't come up with a response
but reminded me...

8x10 enlarger light source - what about an intense tube light moved by a
scanner (stepper) motor close to the negative? It would make a low profile
head, be cool (temp), is programmable (motion rate), and just fill my
weeks with an excuse not to shoot!



It would probably work, but IMHO, you've seriously violated the KISS rule.
In order to get a low profile head and cool temp, you have introduced moving
parts
(possible vibration in the enlarger head) and the heat of the motor. But you
just keep thinking outside the box-- after all, how many light bulbs didn't
work before Edison found one that worked?

How about this idea: use a grid of LED's to light up the whole negative. By
varying the intensity of some of the LED's, you could dodge or burn-in
portions of the negative. With computer control (perhaps a VAX 11/730?), the
manipulation would be repeatable. By using a combination of different color
LED's, you could control the contrast of a print, making a portion higher in
contrast and another portion lower. You could do the same thing with a color
print and adjust the color balance of different parts of the print.

(BTW, if you manage to market this idea, I want a cut!)


  #7  
Old November 13th 08, 02:18 AM posted to rec.photo.darkroom
John J
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Posts: 110
Default Stupid Darkroom Idea

Ken Hart1 wrote:
"John J" wrote in message
m...
The scanner thread pinged my imagination. Didn't come up with a response
but reminded me...

8x10 enlarger light source - what about an intense tube light moved by a
scanner (stepper) motor close to the negative? It would make a low profile
head, be cool (temp), is programmable (motion rate), and just fill my
weeks with an excuse not to shoot!


It would probably work, but IMHO, you've seriously violated the KISS rule.
In order to get a low profile head and cool temp, you have introduced
moving parts (possible vibration in the enlarger head) and the heat
of the motor.


Heat from the light would not be a problem, and suspending the unit a
fraction of an inch above the physical head (from top of column) with
only a compliant bellows might work. (This is a Saltzman enlarger - a
1,000 pound monster.)

But I certainly understand KISS and appreciate the comment. I'm simply
in a bit of despair finding a head for the 10x10, not using it and
falling into strange ideas.

How about this idea: use a grid of LED's to light up the whole negative. By
varying the intensity of some of the LED's, you could dodge or burn-in
portions of the negative.


Well, LEDs have been suggested, and someone out there posted some great
information regarding which type LED to use for polycontrast papers.
I'll have to surf it out and thank the person.

Dodging-burning - to break the KISS rule - I had an early IBM Thinkpad
that had a removable screen that one could lay on a transparency
projector. PING! Idea - use it over a negative with an image of the
negative masked (good old Photoshop 3.0). Never did it. Wasn't KISS.

With computer control (perhaps a VAX 11/730?), the
manipulation would be repeatable.


The VAX 11/730 was the tiny VAX of its time - about the size of a
compact top-loading washing machine. A bit of an adventure for the time
(about 1986) because it had all the system instructions in firmware - an
idea that stopped right there 'cause, well I guess faster everything
else came along. Ancient history.

WOW - I've rambled! I should be printing instead.

OK, if I miraculously come up with something on the scanning light
source, I'll cut you in on the NET.

John
  #8  
Old November 13th 08, 03:43 AM posted to rec.photo.darkroom
Jean-David Beyer
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Posts: 247
Default Stupid Darkroom Idea

John J wrote:

But I certainly understand KISS and appreciate the comment. I'm simply in
a bit of despair finding a head for the 10x10, not using it and falling
into strange ideas.

If money is no object, consider:

http://www.aristogrid.com/cold_light_chart.htm

They might well make you one.

--
.~. Jean-David Beyer Registered Linux User 85642.
/V\ PGP-Key: 9A2FC99A Registered Machine 241939.
/( )\ Shrewsbury, New Jersey http://counter.li.org
^^-^^ 21:35:01 up 6:43, 4 users, load average: 4.60, 4.38, 4.30
  #9  
Old November 13th 08, 05:04 AM posted to rec.photo.darkroom
John J
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Posts: 110
Default Stupid Darkroom Idea

Jean-David Beyer wrote:

If money is no object,


The way the economy is going money will be less than an object - it will
become unobtanium!

My retirement supplement lost 70% this year. Ya think I should just
spend the money now because it will be worthless next year? Serious
question!

consider:
http://www.aristogrid.com/cold_light_chart.htm

They might well make you one.


They have a couple that work out of the box and they are less expensive
than the refurbished Durst (aka: whacky electrics) and others on that
auction site.

I'm reading the docs right now. Pretty good information.

But this chart is soooo confusing to my simple brain:
http://www.digoliardi.net/spectra.gif

Looks like an overlay chart of the stock market, level of banker
freak-out and my boss' tri-polar moods.

One thing that I did not understand was a caution that the head can
overheat and illumination drops. So that means the termostat on the
heating element either is one-way or cooling is not properly managed.
Correct?

Thanks for the pointer, Jean-David. You have always been very helpful.

John
  #10  
Old November 13th 08, 03:11 PM posted to rec.photo.darkroom
Jean-David Beyer
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Posts: 247
Default Stupid Darkroom Idea

Ken Hart1 wrote:
But you just keep thinking outside the box-- after all, how many light
bulbs didn't work before Edison found one that worked?

At least one worked before Edison.

http://en.wikipedia.org/wiki/Joseph_Swan

--
.~. Jean-David Beyer Registered Linux User 85642.
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/( )\ Shrewsbury, New Jersey http://counter.li.org
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