Acetic acid as stop bath for film?

Ray Rogers

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Noweigen Wood Be Hard...


Well, the exposure data might be shutter speed, but that is very unlikely as you observe... probably the 1/1000 sec refers to the flash duration...
which is actually the important data here.

I also assume that there were no typos in the flash duration...
faster speeds might have been posssible at that time....

Was Edgerton's name in there somwhere? I think that was about when he began using strobes....
 

Q.G.

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No, it does not.
A fast flash in a dim room will determine the exposure duration. You could use a hat and not have a shutter at all and do this.
 

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Sure it does! If it was a Leica (Hans Windisch's favorite camera) or a Exakta as I wrote, you SHOULD know they both hafe foical plane shutters, ever tried to sync an old FP shutter at 1/1000th?
)

And 1/1000th for being the STROBE speed: The bullet is stopped in mid-air. I have a pistol like that. The bullet moves at at least 900 feet per second. At 1/1000th would move close to a foot (0,9 feet) and be virtually invisible.
Even at 1/10000th it would be 3 times longer than it is here. Amazing aint it?
 

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Ray Rogers said:
Was Edgerton's name in there somwhere? I think that was about when he began using strobes....
Click to expand...

I have Edgerton's book on early strobe experiments, or maybe it was a book ON Edgerton, I read it 30 years ago..... amazing stuff they did with no technology!
 

Ray Rogers

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Wouldn't the hat/hand combination constitute a "shutter type"?

Even so,
The flash has to fire during a specified time window during the sutter action or faults appear.
 

Ray Rogers

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Yes, I was thinking 1/1000 sounded rather long.

If your math is correct, at 900 fps, what do you calculate the maximum flash duration could have been, to get the image you see/saw?

One third of 1/10,000?
---
BTW?
How do you say "Silver halide emulsion" in Norwegian? ?

They are cool images for sure.
 
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Q.G.

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Erik Prestmo said:
Sure it does! If it was a Leica (Hans Windisch's favorite camera) or a Exakta as I wrote, you SHOULD know they both hafe foical plane shutters, ever tried to sync an old FP shutter at 1/1000th?
)
Click to expand...

I'll explain then.

All te shutter needs to do is be complately open when the flash is fired, for as long, or short, as the flash takes to spend all its energy. It's the flash, not the shutter, that determines exposure duration.
I repeat: not the shutter.

So you can use a shutter speed of several hours, and still be able to stop a bullet in flight.

As long as (there is a condition) there is no other light exposing the film while the shutter is open waiting for the brief flash.
The synch speed is only important to control that other, ambient light. If you cut out all other light, synch speed is completely irrelevant. If light levels are low, the aperture stopped down, even a 1/20 speed may be fast enough to reduce the ambient light exposure enough to be non-existant.
But never will you need a fast synch speed to keep up with a fast flash.

So again: you do not need a fast synch speed for a fast flash, and it does not depend on shutter type.


That's quite true.
So the flash duration must have been much shorter.

Ray Rogers said:
Wouldn't the hat/hand combination constitute a "shutter type"?
Click to expand...

It would, yes.

Ray Rogers said:
Even so,
The flash has to fire during a specified time window during the sutter action or faults appear.
Click to expand...

Indeed: the flash has to fire while the shutter is fully open.
Not difficult to achieve, that. No need for a fast synch speed for that either. Nor does it depend on shutter type.


By the way: modern (1960-1970's onward) consumer flash units have no problem producing bursts as short as 1/50,000 or shorter.
But Windisch wouldn't have had one of these yet.
 
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I routineously reloaded ammo for my 9mm Kurz postolet to 950 FPS, a little higher than stated.

From the picture I'd say a bullet that is a bit under 1cm have moved about half of that, i.e. the bullet is now elongated in the picture, about 1,5cm long it appears.

950 fps = 290 m/sec or 29 000 cm/sec

at 1/1000th the movement would be 29cm, nearly a foot.
at 1/10 000th movent would be 2,9cm
at 1/ 100 000th movement would be 0,29 cm

I recon it was about double of the last, this bullet moved approximately 0,6cm, and that would mean the strobe speed was around 1/50 000th of a second, pretty much state of the art back in 1955.

The picture has a byline, stating it was one Dr. Rebikoff who made it, and purely from memory, I seem to remember one by that name that worked with Dr. Edgerton in his lab.

Best bet in a setting like that is a darkened room and a central type shutter, which will be fully open during its cycle, and can be synced at any speed (but delay has to be adjusted prescisely).

If it was a focal plane shutter, in that time-frame, anything shorter than 1/20th of a second would render a partially exposed image (with an electronic strobe!!!), at 1/50 only about half of the image is exposed, at 1/1000th exposure would be seen as a 1mm to 2mm thin stipe covering the negative. The rest would be hopelessly underexposed.


"Silver halde emulsion" translated into norwegian : "Sølvhalid emulsjon"
We have a knack for pulling woirds together into one, and swallowing half of the expected sounds! That was probably because the vikings couldn't waste much time talking while beheading monks in England!
 

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Q.G. said:
No, it does not.
A fast flash in a dim room will determine the exposure duration. You could use a hat and not have a shutter at all and do this.
Click to expand...

Only with a central shutter, NEVER with a focal plane shutter, where the whole point is a partial covering of the neagtive at fast speeds, this is the very nature of shutters like that.

- Modern FP shutters does better than 1950's because of thwo things: vertical travel is faster, hence they will be fully open at shorter shutter speeds.

- Modern shutters are electrocally controlled, hence stronger springs can drive the shutter curtains, which again yelds shorter sync speeds. Typically the sync speed came down from 1/20 in an old Leica to 1/125th in a late 1970's Canon SLR.

MARK THIS: this only is important for electronic flash, back in the day we used flash bulbs that could be made to have a longer burning time thjan 1/20 of a second, anhence allow shorter sync speeds. These bulbs was known as FP bulbs, but would "stop nothing"!


PS, I think we have yet again strayed from the thread here, stop BATHs wasn't it, nothing about flash stopping a speeding bullet??
Sorry 'bout that )
 

Q.G.

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For a Viking in a hurry, you take your time getting your head round the idea : once more (and then i think i give up): in that setting you describe, you do not need "a central type type shutter, which will be fully open during its cycle, and can be synced at any speed (but delay has to be adjusted prescisely)."

Delay does not need to be adjusted either.
All that is needed is that the shutter (whatever it is: a lens cap will do) is open when the flash is fired.
 

Q.G.

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Erik Prestmo said:
Only with a central shutter, NEVER with a focal plane shutter, where the whole point is a partial covering of the neagtive at fast speeds, this is the very nature of shutters like that.
[...]
Click to expand...

Ok. Despite my previous post: once more.

The problem you are looking at is that of a shutter not being fully open when the flash occurs.
Instead of looking for the obvious, i.e. use any speed at which the shutter is fully open = SLOW speeds, you are heading in the wrong direction entirely, looking for shutters that are fully open at short speeds.

The shutter does not need to be fast. The flash is fast.

Think about that for a while.

Then you will see (i hope) that an old hat, a lens cap, a newspaper, or even nothing at all would do as a shutter, i.e. you do not even need a shutter for this type of photography.
 

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You might as well give up, because you fail to acknowledge what I described as a probable scenario IF mr. windis did shoot that picture, a camera with a FOCAL PLANE SHUTTER, the rest is just the usual net chatter.

If it was a FP shutter, it would partially covewr most of the negative while a slit slowly passed beore the film (at 1/1000th of a second) the travel time would still be 1/20th of a second, this means the travel time is 50 times longer than the effective exposure, in other words only about 1/50th of the frame length is exposed at any time, and that means only 1/50 of 36 millimeter negative length will "see" the electronic flash.

You most definitely will need some type of apparatus that leaves a totally exposed film frame to make a picture like that.

Now all this is moot an without any interest, because it turns out the picture wasn't actually made by Mr. Windisch, but another gentleman, who probably used lab equipment, most likely a lab camera with no shutter in the sense we mean by that word, and no camera in our sense of the word either, for that matter. A flash exposure of 1/50 000th of a second back before 1955 required massive equipment, Mr. Edgertons book illustrates some of it, it can hardly be described as "handheld".
 

Q.G.

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Yes.
And a focal plane shutter (oops! a FOCAL PLANE SHUTTER, i mean) set to B is exactly that. Keep it open for 13.5987 hours, and it is that too.
Or to any other speed at which it is fully open, i.e. any speed upto and including the synch speed.
How fast that speed is, how long the shutter is open, is of no importance whatsoever.
As little as what type of shutter it is: a FOCAL PLANE SHUTTER, a leaf shutter, and old hat, your car's gas cap, whatever.

It is as simple as that.
But you are not really trying to understand, are you?
That is indeed typical internet behaviour...
 

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Im not looking, I'm stating what the book SAYS.

And stating that what the books says, most assuredly is wrong, either way you see it.

The picture:
It could NOT ahve been made at a shutter speed of 1/1000 of a second. (I'm not familiar with central shutters capable of 1/1000th of a second, are you?)
And it could NOT have been made with an electronic strobe as slow as 1/1000th of a second, given the subject matter (I'm not familiar with flash bulbs able to deliver 1/1000th of a second are you?)

Have YOU seen the picture your so active debating?

LOL!
 

Q.G.

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Erik Prestmo said:
Sure thing somebody is debating an unseen picture!
Click to expand...

Someone is failing to see the nonsense of what he is saying.

I haven't seen the picture.
I have seen what you said. And it really is nonsense. And that's what i'm "debating".

And you really are not even trying to understand basic things. So how do you expect to understand how the picture that you have seen is made? No chance in hell...


Oh and: though it is neither here nor there, completely irrelevant, yes, i do know central shutters that do 1/1000.
 

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Is there a way for ME to lock out individuals on this forum from what I see, so I don't have to be bothered with types like this?

After spending too much time on the net with types debating seven angels dancing on a pin head I have only one thing to say

"Every time I try to get out, they suck me right back in!"

But you fezzed up and said you never saw the picture, so whats the big deal?
 
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Photo Engineer

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A focal plane shutter varies its exposure duration by varying the width of separation of the two curtains while the shutter itself moves at nearly constant speed at all exposure speeds. Therefore at long exposure times, the shutters leading edge moves across, followed by the trailing edge such that every area of the film gets say 1/25th second. You can actually see the leading and trailing edges if you watch with the camera back open.

With a fast shutter, the leading and trailing edges are so close you just about cannot see that they are separated, but there is just enough to give the degree of exposure desired such as 1/2500th second.

FP shutters are not ideal for taking pictures of moving objects as they distort the object in the direction of the movement of the object, and thus horizontal FP shutters make moving objects appear longer or shorter. Vertical FP shutters distort moving objects from top to bottom making them appear bizarre.

For this reason, leaf shutters are to be preferred for taking high speed photos. Typically, at 2500 ft/sec the exposure by flash is about 200 micro seconds and an energy of 150 joules.

Reference: The High Speed Photography of Liquid/Solid Impact, J. H. Brunton, Proceedings of the 5th International Congress of High Speed Photography.

We hosted this conference regularly at Cape Canaveral as we had to do so much high speed photography.

PE
 

richard ide

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Tongue in cheek. Maybe they borrowed from aerial photography where the film moves behind the lens to compensate for subject movement during exposure.
:munch:
 

Ian Grant

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As usual there's too many assumptions A Focal Plane shutter speed can vary depending on the tensioning of the mechanism and operate with a fixed width. Some of the earliest high speed focal pane shutters worked this way, with a fastest speed of 1/180th of a second

My Avatar is the Speed dial of just such a shutter (one I restred recently) albeit not the high speed model, rather a slightly more modest 1/90th.

Kodak were still selling this type of Thornton Pickard shutter in 1940, however they incorrectly described them as having two separate curtains in their catalogue, the shutter design (and Illustration) was identical to the original 1888 versions.

Other Focal plane shutters used a combination of variable tensioning and different fixed slit widths - Graflex etc.

Can Acetic acid be used to stop these shutters faster

Ian
 
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Acetic acid can of course be used to stop anything mechanical dead in its tracks!


But it is not universally advocated by the suppliers, some say you can use it, or not, its up to you!
 

Ian Grant

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Erik Prestmo said:
Acetic acid can of course be used to stop anything mechanical dead in its tracks!

But it is not universally advocated by the suppliers, some say you can use it, or not, its up to you!
Click to expand...

Joking apart I do use acetic acid on shutters, well vinegar usually, to clean brass-work and I can confirm the shutter does indeed stop working while it's applied

Ian
 
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