Anyone Heard the Omega D5V-XL Enlarger?

On 15 Apr 2005 23:06:09 -0700, "narke" wrote:

Assuming an enlarger without a shutter, such as the OP's Omega
D5V-VL, wouldn't this "up-glow" and "down-glow" (cute terminology!)
cause a color problem? As the lamp is coming up (or going down),
wouldn't it go thru various shades of yellow/red until it gets to
operating temp? With my Omega D2V (using a "household-style" lamp:
PH112? with no noticeable up/down-glow), my exposures for 11x14 on
Kodak Endura paper typically run 10sec +/-. If the glow lasts a second
or more, that's possibly 10% or more of the exposure.

Yes, that's what i am worry about.


apr1605 from Lloyd Erlick,

I believe this is an unnecessary concern. Working at a smaller
aperture would extend the exposure to the point the percentage of
overall energy reaching the paper from the combination of up- and
down-glow would be small enough to be called insignificant.

regards,
--le
________________________________
Lloyd Erlick Portraits, Toronto.
voice: 416-686-0326
email:
net: www.heylloyd.com
________________________________
--

I believe this is an unnecessary concern. Working at a smaller
aperture would extend the exposure to the point the percentage of
overall energy reaching the paper from the combination of up- and
down-glow would be small enough to be called insignificant.

did you consider cases when need to split a whole exposure in to five
or more splits?

On Sat, 16 Apr 2005 14:43:42 -0400, Lloyd Erlick Lloyd at @the-wire. dot com wrote:

apr1605 from Lloyd Erlick,

I believe this is an unnecessary concern. Working at a smaller
aperture would extend the exposure to the point the percentage of
overall energy reaching the paper from the combination of up- and
down-glow would be small enough to be called insignificant.

regards,
--le

As I stated earlier I never actually ran into a problem caused by this
characteristic because I keep my times longer than 10 seconds. I usually target 15
seconds. The final effect is that the print (which is a very slow media anyway) does not
shift colors to any significant degree as far as I can tell. And I've probably printed
thousands more color prints than most.

JD - www.puresilver.org

"Ken Hart" writes:

Assuming an enlarger without a shutter, such as the OP's Omega
D5V-VL, wouldn't this "up-glow" and "down-glow" (cute terminology!)
cause a color problem? As the lamp is coming up (or going down),
wouldn't it go thru various shades of yellow/red until it gets to
operating temp? With my Omega D2V (using a "household-style" lamp:
PH112? with no noticeable up/down-glow), my exposures for 11x14 on
Kodak Endura paper typically run 10sec +/-. If the glow lasts a
second or more, that's possibly 10% or more of the exposure.

More like 1%, the spectrum heads into the red/IR real fast! Your
eye can see it OK, but it makes very little difference to the exposure.
Doing many cycles for dodging etc is another matter if your
exposure is lots of short times.

--
Paul Repacholi 1 Crescent Rd.,
+61 (08) 9257-1001 Kalamunda.
West Australia 6076
comp.os.vms,- The Older, Grumpier Slashdot
Raw, Cooked or Well-done, it's all half baked.
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On 16 Apr 2005 20:28:11 -0700, "narke" wrote:

I believe this is an unnecessary concern. Working at a smaller
aperture would extend the exposure to the point the percentage of
overall energy reaching the paper from the combination of up- and
down-glow would be small enough to be called insignificant.

did you consider cases when need to split a whole exposure in to five
or more splits?


apr1705 from Lloyd Erlick,

A five exposure cumulative exposure would most likely not be ten
seconds overall. When I do that sort of thing I do not want any one of
the five segments to be as short as ten seconds. Therefore, for any
given exposure or partial exposure, the ratio of "up- and down-glow"
to the exposure itself remains insignificantly low.

Even if it were significant, it would simply be part of the overall
exposure, and therefore it would be taken into account by the process
of doing test strips and test prints until one arrives at the
'correct' exposure.

These problems-in-advance are kind of like discussing how to tie
shoelaces. So much easier to put on the skates and see how it goes. No
doubt your ankles will wobble for a while and you'll fall on the ice,
but you'll be in a situation where your own intelligence will take
over and make corrections over time.

regards,
--le
________________________________
Lloyd Erlick Portraits, Toronto.
voice: 416-686-0326
email:
net: www.heylloyd.com
________________________________
--

On 16 Apr 2005 20:28:11 -0700, "narke" wrote:

I believe this is an unnecessary concern. Working at a smaller
aperture would extend the exposure to the point the percentage of
overall energy reaching the paper from the combination of up- and
down-glow would be small enough to be called insignificant.

did you consider cases when need to split a whole exposure in to five
or more splits?


apr1705 from Lloyd Erlick,

A five exposure cumulative exposure would most likely not be ten
seconds overall. When I do that sort of thing I do not want any one of
the five segments to be as short as ten seconds. Therefore, for any
given exposure or partial exposure, the ratio of "up- and down-glow"
to the exposure itself remains insignificantly low.

Even if it were significant, it would simply be part of the overall
exposure, and therefore it would be taken into account by the process
of doing test strips and test prints until one arrives at the
'correct' exposure.

These problems-in-advance are kind of like discussing how to tie
shoelaces. So much easier to put on the skates and see how it goes. No
doubt your ankles will wobble for a while and you'll fall on the ice,
but you'll be in a situation where your own intelligence will take
over and make corrections over time.

regards,
--le
________________________________
Lloyd Erlick Portraits, Toronto.
voice: 416-686-0326
email:
net: www.heylloyd.com
________________________________
--

"Lloyd Erlick" Lloyd at @the-wire. dot com wrote in message
...
A five exposure cumulative exposure would most likely not be ten
seconds overall. [...]

What Lloyd asserts is absolutely correct. Five, two-second exposures is not
the same as a single 10-second exposure. _That's_ why the prudent printer
does many test strips, including tests of the multiple-exposure areas -
exposed in multiple steps.

That said, I have no problems with my D5 and color head. Yet. But I would
much rather have a condenser setup, and to that end I'm still looking.
Finding a clean one is difficult.

Oh - to the OP - just a reminder that there is a High/Low switch on the
head. If your exposures are too long, check it out.

"Lloyd Erlick" Lloyd at @the-wire. dot com wrote in message
...
A five exposure cumulative exposure would most likely not be ten
seconds overall. [...]

What Lloyd asserts is absolutely correct. Five, two-second exposures is not
the same as a single 10-second exposure. _That's_ why the prudent printer
does many test strips, including tests of the multiple-exposure areas -
exposed in multiple steps.

That said, I have no problems with my D5 and color head. Yet. But I would
much rather have a condenser setup, and to that end I'm still looking.
Finding a clean one is difficult.

Oh - to the OP - just a reminder that there is a High/Low switch on the
head. If your exposures are too long, check it out.

Many short exposures do equal one equivalent long one,
except when they don't.

Test your own system. You will need a digital timer,
if you are using a Gralab all bets are off.

Use variable contrast paper with a 5+ filter.
Set the aperture etc. so a 20 second exposure
yields a mid grey with no negative.

Do the the test on a single sheet of paper: cover
half and make a 20 second exposure, cover the other
half and make 20 two second ones. Develop, cut the
center strip out and butt the two halves.

My experience.

o Incandescent light bulb: The two are the same. GE
212 (? or something) enlarger bulb, my own f-stop
timer, Beseler 45, Ilford MC IV, 5+ polymax filter.

o Aristo cold-light head warmed for 1/2 hour,
original tube. As above, with a Besler digital
timer. Nowhere close.

Cold light systems with compensating timers should
have no trouble. If a compensated timer system can't
pass the test then the timer isn't doing it's job.
If there is a problem it may be: 1) the photodiode
has a different spectral response from the paper - there
should be a cyan filter over it; 2) the system uses a
CDS cell that has a long 'memory'; 3) the timer is
bust/badly designed.

Timers that compensate for a cold-light's dead
time should do better than those that don't.

Shuttered systems should also do well. Pulsed
xenon is pretty linear (or it should
be if the power supply is well designed).

I have no experience with halogen light (slide
projector bulb) systems.

--
Nicholas O. Lindan, Cleveland, Ohio
Consulting Engineer: Electronics; Informatics; Photonics.
To reply, remove spaces: n o lindan at ix . netcom . com
psst.. want to buy an f-stop timer? nolindan.com/da/fstop/

"Nicholas O. Lindan" wrote in message
ink.net...
Many short exposures do equal one equivalent long one,
except when they don't.

Come on, Nicholas - it's a matter of physics. Perhaps we should qualify the
case: multiple short exposures, for example 2 to 5 seconds each, not two
20-second exposures.