Patt.23 Question

[Keeper of the Keys]

In a wikipedia article about stage lighting in Dutch someone writes something about Strand Patt. 23 spots which to me sounds like quite a load of nonsense (except for the nickname s/he mentions).

Now I have worked/seen these lamps a few times but not often enough to truly know if this is true or as I suspect not.

 

I have included google translation of the section in question nd was wondering if anyone can comment on it's accuracy nd maybe enlighten me/others as to what is meant by the BiFocal which is so impartant that it became a nickname for instance

 

I have read strand archive about the lanters and still feel that this is nonsense but I am hoping some expert peer review will help...

Thanks

 

Another type of profile is the so-called spotlight Bifocal projector (BiPo in Dutch is corrupted to the word Pipo) the spotlight is instead a set of shutters, two sets, a set of straight and serrated set.

 

This can therefore choose to focus the beam, for example the right to cut and left blurred. Although you have a nice BiPo effects can create this kind of spotlight is not really practical to work with, this is also one of the reasons that the BiPo in the Dutch theaters almost no longer in use.

source: http://nl.wikipedia.org/wiki/Theaterbelichting#Bipo / google translate

[Bryson]

Never seen a bifocal Patt 23 before, but the feature was part of the 264/764 lanterns.

 

It basically let you have in-focus and out-of-focus shutter cuts in the same lantern.

[J Pearce]

Some Patt23s, (Mk2s?) did have both hard and soft edged shutters, which are incredibly useful. Also found on the T Spot (though rarely seen due to the lack of light found to emanate from a T Spot), and on 264/764s.

 

To be honest the main reason they went out of fashion is that better, more efficient, sharper focus, flatter beam etc profiles became available, and gradually everyone upgraded.

Still a lot out there though, many still being used for odd little jobs and as reserve backups.

 

[edit]

According to Strand Archive Bryson is right (as always), though I'm sure I've focussed a Patt23 that had double shutters. Perhaps it was some mongrel that someone had created.

[Keeper of the Keys]

Would I be correct in saying that you could get the soft edge effect on any profile spot as long as you have a shutter that is toothed instead of straight? (That seems to be logical but I could be wrong)

[J Pearce]

You can do it with a hard edged shutter by de-focussing the lens from hard edged.

 

The two shutters concept was more clever in that it allowed you to simultaneously have hard and soft edges from the same lantern.

For example, a hard edge to miss the prosc border, but a soft edge to blend in with the next profile along.

[Bryson]

No - the toothed edge was an extra way to "fuzz" the image. It was soft edged because the second set of shutters were not in the focal plane of the lantern - they were a touch forward. Have a look at the link in my post above - that explains it.

[Keeper of the Keys]

Thanks a lot! (so far, more info is always welcome )

[gareth]

Some Patt23s, (Mk2s?) did have both hard and soft edged shutters

Wrong. There was never a Patt23 with bifocal shutters. Bryson was right in the post prior to yours.

[paulears]

Concur - the bifocal gate in the 264/764 range used the standard shutter assembly with another fitted in front with the red knobs and vignetted shutter blades. The extra assembly was connected to the first with standoff bolts and sleeves. The Patt. 23, even the Mk2, was a very different casting and adding on the extra 30-40mm that the extra set of shutters required would have also wrecked the optics - moving the lens much further away, which would have needed some changes. I've had a check through the old Strand catalogues I have here and there is no mention of a bifocal version, which is also what my memory tells me.

[Roderick]

It looks like the 'contributor' of that Wiki information got a little confused.

The term Bipo in Dutch theatre referred to all profile type luminaires and was based on the two lenses (Bi=two), not two sets of shutters.

Only the Patt23 was referred to as a Pipo, basically to indicate its' smaller size and 500W vs 1kW which was the standard for a Bipo.

I believe the term Bipo was originally introduced by Reiche & Vogel.

[J Pearce]

Some Patt23s, (Mk2s?) did have both hard and soft edged shutters

Wrong. There was never a Patt23 with bifocal shutters. Bryson was right in the post prior to yours.

 

Alright, I did say in my edit that I could well have been wrong. Chill out a bit!

[paulears]

Sorry - we didn't mean to upset anyone, but the Strand history is an important one, so finding out new info is always the cue to go into the loft to check that I'd not missed something important, and after poring over the material gleaned when I was a kid and carefully stored, I thought it important to correct the slip. It isn't important, I suppose, but I personally think the short lived (in Strand terms) Bifocal period was pretty badly managed by them - such a useful and quite simple feature just getting thrown away. As it's history, it does need to be accurate. If I upset anyone, I'd like to assure them it wasn't personal, and if anyone felt upset, I can assure them the last thing in my mind was that they could have taken it to heart - and if my attempt to put the record straight did cause distress, I apologise sincerely.

Paul

[Neil Hampson]

What could have added to the confusion is the Patt.23W, that had a second lens to make a wider beam version. for a Wiki entry from a person whose 1st language is not English, Bi-focal could be mis-interpreted as meaning having two lenses, rather than the double shutter sets that we know it means.

[Keeper of the Keys]

Wow thanks for all this information :unsure:.

These lanterns are from well before my time and though I have worked with them once or twice in small venues that is not enough exposure to really know enough.

I assume Roderick that you are originally from Holland as you know the history of this name, thanks a lot.

 

I have some more history question, should I open new topics for the sake of order or should I just add it here?

[Bryson]

Here's fine. We can split it if it's too different...