Anyone aware of a make / model that used mercury or other discharge lamp
light source for conventional ie 35mm photographic format slides, not
scpecialised large format systems

I'm a bit lost, here.

Discharge lamps are not continuous-spectrum sources, and would probably not
work very well when projecting color images. And with mercury, you'd have to
filter out the UV, not to mention the ozone generated by the UV.

William Sommerwerck wrote in message
...
I'm a bit lost, here.

Discharge lamps are not continuous-spectrum sources, and would probably
not
work very well when projecting color images. And with mercury, you'd have
to
filter out the UV, not to mention the ozone generated by the UV.




So am I, video projectors and back projected TVs seem to manage fine.

N_Cook wrote:

William Sommerwerck wrote in message
...
I'm a bit lost, here.

Discharge lamps are not continuous-spectrum sources, and would probably
not
work very well when projecting color images. And with mercury, you'd have
to
filter out the UV, not to mention the ozone generated by the UV.



So am I, video projectors and back projected TVs seem to manage fine.


They don't melt or burn like film does.


--
You can't fix stupid. You can't even put a Band-Aid™ on it, because it's
Teflon coated.

On Mar 1, 7:01*am, "N_Cook" wrote:
William Sommerwerck wrote in message

...

I'm a bit lost, here.

Discharge lamps are not continuous-spectrum sources, and would probably
not
work very well when projecting color images. And with mercury, you'd have
to
filter out the UV, not to mention the ozone generated by the UV.

So am I, video projectors and back projected TVs seem to manage fine.

Well, at the very least the 'image' can be electronically colour
corrected to compensate for the uneven spectrum of the source. On the
other hand, one probably only needs to to provide illumination in the
3 [or 4??] colour layers that slides use.
I have not noticed any 'ozone' smell around mid-sized video
projectors, so what's with that?

Neil S.

In article ,
William Sommerwerck wrote:
Discharge lamps are not continuous-spectrum sources, and would probably
not work very well when projecting color images. And with mercury, you'd
have to filter out the UV, not to mention the ozone generated by the UV.

They're used for lighting on film and TV so can be pretty good. As well as
for DLP etc projectors.

--
*A 'jiffy' is an actual unit of time for 1/100th of a second.

Dave Plowman London SW
To e-mail, change noise into sound.

On Tue, 01 Mar 2011 10:56:02 +0000, N_Cook wrote:

Anyone aware of a make / model that used mercury or other discharge lamp
light source for conventional ie 35mm photographic format slides, not
scpecialised large format systems

Do you need one or are you just thinking out loud? Are 35mm slides still
popular? If you're not seeing them maybe the technology isn't calling for
discharge illumination.



--
Live Fast, Die Young and Leave a Pretty Corpse

Meat Plow wrote in message
news
On Tue, 01 Mar 2011 10:56:02 +0000, N_Cook wrote:

Anyone aware of a make / model that used mercury or other discharge lamp
light source for conventional ie 35mm photographic format slides, not
scpecialised large format systems

Do you need one or are you just thinking out loud? Are 35mm slides still
popular? If you're not seeing them maybe the technology isn't calling for
discharge illumination.



--
Live Fast, Die Young and Leave a Pretty Corpse


Just curious. Just repaired a Kodak carousel projector with 300W bulb and
wondered what the power requirement for a lumen for lumen equivalent
discharge lamp would be , or is it just smps gives the edge.
But then is there a problem with smps supplying a filament lamp, in the way
of thermal runaway

On Tue, 01 Mar 2011 15:59:23 +0000, N_Cook wrote:

Meat Plow wrote in message
news
On Tue, 01 Mar 2011 10:56:02 +0000, N_Cook wrote:

Anyone aware of a make / model that used mercury or other discharge
lamp light source for conventional ie 35mm photographic format
slides, not scpecialised large format systems

Do you need one or are you just thinking out loud? Are 35mm slides
still popular? If you're not seeing them maybe the technology isn't
calling for discharge illumination.



--
Live Fast, Die Young and Leave a Pretty Corpse


Just curious. Just repaired a Kodak carousel projector with 300W bulb
and wondered what the power requirement for a lumen for lumen equivalent
discharge lamp would be , or is it just smps gives the edge. But then is
there a problem with smps supplying a filament lamp, in the way of
thermal runaway

I think the technology is stagnant. Same goes for home movies on film.

There isn't sufficient need to improve the design.



--
Live Fast, Die Young and Leave a Pretty Corpse

Just curious. Just repaired a Kodak carousel projector with
a 300W bulb and wondered what the power requirement for
a lumen for lumen equivalent discharge lamp would be, or is
it just smps gives the edge. But then is there a problem with
smps supplying a filament lamp, in the way of thermal runaway

I think the technology is stagnant. Same goes for home movies
on film. There isn't sufficient need to improve the design.

Agreed. Slide projectors never got past tungsten-halogen lighting.

Discharge lamps would no doubt be more efficient. But... not only would you
have to correct for color balance, but the bulb would have to be "mated" to
the projector's optical system.

On Tue, 01 Mar 2011 09:04:28 -0800, William Sommerwerck wrote:

Just curious. Just repaired a Kodak carousel projector with a 300W
bulb and wondered what the power requirement for a lumen for lumen
equivalent discharge lamp would be, or is it just smps gives the edge.
But then is there a problem with smps supplying a filament lamp, in
the way of thermal runaway

I think the technology is stagnant. Same goes for home movies on film.
There isn't sufficient need to improve the design.

Agreed. Slide projectors never got past tungsten-halogen lighting.

Discharge lamps would no doubt be more efficient. But... not only would
you have to correct for color balance, but the bulb would have to be
"mated" to the projector's optical system.

Large theater projectors are still an arc light ? There must be some
sort of white/color balancing scheme for them. Same could be used on
other forms of HID illumination.



--
Live Fast, Die Young and Leave a Pretty Corpse