Speed of a rotary tube processor

Hello everybody:

Does anybody know wich is the normal speed of the tank in a rotary tube
processor? I'm good at building things and I've made a home made rotary tube
processor, but I still do not know wich is the 'correct' speed for the tank.
I've been searching the web and I've found that there is a Jobo processor
that goes at 75RPM, but that seems to be too much for the tank, and must be
the speed of the engine or some internal plate. Could anybody help me?

Thank you

Manuel

"Manuel \(MrFloyd\) Portillo Pérez" wrote:
Hello everybody:

Does anybody know wich is the normal speed of the tank in a rotary tube
processor? I'm good at building things and I've made a home made rotary tube
processor, but I still do not know wich is the 'correct' speed for the tank.
I've been searching the web and I've found that there is a Jobo processor
that goes at 75RPM, but that seems to be too much for the tank, and must be
the speed of the engine or some internal plate. Could anybody help me?

No, 75 RPM is exactly correct, even with Jobo 2500 drums. The large Jobo
3000 expert drums use 50 RPM, but all smaller tanks 75RPM.

Martin

"Martin Jangowski" wrote in message
...
"Manuel \(MrFloyd\) Portillo Pérez" wrote:
Hello everybody:

Does anybody know wich is the normal speed of the tank in a rotary
tube
processor? I'm good at building things and I've made a home made rotary
tube
processor, but I still do not know wich is the 'correct' speed for the
tank.
I've been searching the web and I've found that there is a Jobo
processor
that goes at 75RPM, but that seems to be too much for the tank, and must
be
the speed of the engine or some internal plate. Could anybody help me?

No, 75 RPM is exactly correct, even with Jobo 2500 drums. The large Jobo
3000 expert drums use 50 RPM, but all smaller tanks 75RPM.

Presented that way, it does sound frantically fast, but it's only 1.25
revolutions per second, or a little more than 1 mph on the drum surface.

In article ,
Martin Jangowski wrote:

No, 75 RPM is exactly correct, even with Jobo 2500 drums. The large Jobo
3000 expert drums use 50 RPM, but all smaller tanks 75RPM.
Martin

I set my 3000 drum a little slower than that, more like 35-40 Rpm for film.
--
LF Website @ http://members.verizon.net/~gregoryblank

"To announce that there must be no criticism of the President,
or that we are to stand by the President, right or wrong,
is not only unpatriotic and servile, but is morally treasonable
to the American public."--Theodore Roosevelt, May 7, 1918

Thank you all. That 75RPM still seems very fast to me. I'm not saying that
speed is not the normal one for small processors, of course if you own a
processor you know wich is that normal speed, much better than I do. Maybe I
do not understand the whole thing, or I did not ask the right question. Do
you develop B/W films in the processor? How do you change film speed or
development time for that 75RPM for each kind of film and developer?

I've set my machine to 75RPM, after changing a couple of gears, because it
was set to maximum of 7RPM, and the tank goes really fast. When the tank is
filled with developer and films the movement inside must be a mess!. (LOL)

What I am really looking for is for the equivalent speed to the famous
Kodak's manual agitation speed of 5 seconds every 30 seconds of development,
so I do not have to change development times. And that speed can't be 75RPM
(I feel) .Or is it? I've been developing B/W at this manual agitation rate,
and color slides with de double (5 seconds every 15 seconds) with good
results and I would like to keep development times. The reason for this is
that I've achieved a good balance between lights, shadows and 'gray'
mid-tones, particulary with plus-X and provia, and setting an agitation that
keeps the development times makes me think of keeping that same balance.

I would appreciate any suggestion.

Manuel

"Manuel \(MrFloyd\) Portillo P?rez" wrote:


I've set my machine to 75RPM, after changing a couple of gears, because it
was set to maximum of 7RPM, and the tank goes really fast. When the tank is
filled with developer and films the movement inside must be a mess!. (LOL)

I use the Jobo tanks on a uniroller. What the motor does is about 1.5
turns one way. Then back the other. Supposedly reversing direction breaks up
any waves inside the tank.


What I am really looking for is for the equivalent speed to the famous
Kodak's manual agitation speed of 5 seconds every 30 seconds of development,
so I do not have to change development times. And that speed can't be 75RPM
(I feel) .Or is it? I've been developing B/W at this manual agitation rate,
and color slides with de double (5 seconds every 15 seconds) with good
results and I would like to keep development times. The reason for this is
that I've achieved a good balance between lights, shadows and 'gray'
mid-tones, particulary with plus-X and provia, and setting an agitation that
keeps the development times makes me think of keeping that same balance.


The tank needs to be in constant motion. If it's too slow you'd find the
liquid would pool in the bottom and the film wouldn't spend enough time in
it. With the motor spinning the drum a relatively small amount of liquid
basically spins around the inside wall of the tank. If you look at the Jobo
recommendations for the amount of liquid in a tank you'll notice different
formats have different requirements. The reason is the something like 35mm
that fills a reel is further from the wall. A single roll of 120 on the reel
doesn't go that far so you can use less liquid. You might be able to slow
the motor down by using more liquid in the tank but that means testing.

I know Jobo claims that with a 5 minute pre-soak you can use the same
times with B&W but if you look at the unblinkingeye.com website article on
rotating that a real lack of rhyme or reasons exists. It's best to just
spend some time testing your setup.


http://unblinkingeye.com/Articles/Rotary/rotary.html

Nick

"Manuel \(MrFloyd\) Portillo Pérez" wrote in message ...
Hello everybody:

Does anybody know wich is the normal speed of the tank in a rotary tube
processor? I'm good at building things and I've made a home made rotary tube
processor, but I still do not know wich is the 'correct' speed for the tank.
I've been searching the web and I've found that there is a Jobo processor
that goes at 75RPM, but that seems to be too much for the tank, and must be
the speed of the engine or some internal plate. Could anybody help me?

Thank you

Manuel

75 RPM is the actual speed on position "P" (for "P"aper, but it's
actually the speed used mainly for films too) of Jobo processors.
This is really the tank speed and it can be adjusted continuously from
around 25 to 80rpm.

Regards,
Claudio Bonavolta
http://www.bonavolta.ch

I havent' seen it mentioned, but the JOBO reverses itself about every 1.5
turns. About 6 years ago there seemed to be repetitive threads on failure
of the JOBO motors -- I found that it wasn't the motor problem so much as
the controller -- or that the problem could be fixed with a higher voltage
on the motor windings --

I have the circuit on the following site: http://www.tech-diy.com/jobo.htm
which uses a National Semi motor controller chip (LMD18201) to keep the
voltage on the motor windings "high" but uses pulse width modulation to
control the speed. Here's the schematic:
http://www.tech-diy.com/jobo_schematic.htm

Of course, the other thing which I should have done would have been to put
in a "counter" chip which would reverse the polarity of the windings
electronically -- dispensing with the electromechanical switch. The switch
isn't problematic, however.


"Manuel (MrFloyd) Portillo Pérez" wrote in
message ...
Thank you all. That 75RPM still seems very fast to me. I'm not saying that
speed is not the normal one for small processors, of course if you own a
processor you know wich is that normal speed, much better than I do. Maybe
I
do not understand the whole thing, or I did not ask the right question. Do
you develop B/W films in the processor? How do you change film speed or
development time for that 75RPM for each kind of film and developer?

I've set my machine to 75RPM, after changing a couple of gears, because it
was set to maximum of 7RPM, and the tank goes really fast. When the tank
is
filled with developer and films the movement inside must be a mess!. (LOL)

What I am really looking for is for the equivalent speed to the famous
Kodak's manual agitation speed of 5 seconds every 30 seconds of
development,
so I do not have to change development times. And that speed can't be
75RPM
(I feel) .Or is it? I've been developing B/W at this manual agitation
rate,
and color slides with de double (5 seconds every 15 seconds) with good
results and I would like to keep development times. The reason for this is
that I've achieved a good balance between lights, shadows and 'gray'
mid-tones, particulary with plus-X and provia, and setting an agitation
that
keeps the development times makes me think of keeping that same balance.

I would appreciate any suggestion.

Manuel

"Manuel \(MrFloyd\) Portillo P?rez" wrote:
: Hello everybody:

: Does anybody know wich is the normal speed of the tank in a rotary tube
: processor? I'm good at building things and I've made a home made rotary tube
: processor, but I still do not know wich is the 'correct' speed for the tank.
: I've been searching the web and I've found that there is a Jobo processor
: that goes at 75RPM, but that seems to be too much for the tank, and must be
: the speed of the engine or some internal plate. Could anybody help me?

The tank on a Jobo rotates at 75rpm.

--




Keep working millions on welfare depend on you
-------------------

"Manuel (MrFloyd) Portillo Pérez" wrote

Does anybody know wich is the normal speed of the tank in a rotary tube
processor?

18 rpm:

A Jobo drum on a Unicolor base. It runs 1 1/3 turns before reversing.
Each forwards and back again cycle takes 9 seconds. 18rpm is the resulting
speed.

This is not a standard speed/time though: the drum and the base are
not designed for each other. OTOH, the combination works very well:
uniform, predictable results that match published times.

The base (used) cost $10 at the local photo store.

--
Nicholas O. Lindan, Cleveland, Ohio
Consulting Engineer: Electronics; Informatics; Photonics.