(Film) How to get great exposure without aperture needle?

I think I have a link to a website in russia that would sell the real mercury batteries. Not that expensive. I don't try to use them because meters of those era are not very accurate any way.

That's where I bought them.

The batteries themselves aren't super expensive. Shipping drives them up on a per-cell basis unless you buy a bunch.

A friend of mine at school was doing experiments in a physics class with mercury (remember the happy days when kids were trusted with this stuff?) and at one point went up to the teacher, poked a shiny metal bead around on his hand for a second, said "this stuff is weird", and popped it in his mouth. The teacher's reaction was fairly priceless, until it was pointed out to him that the friend had just borrowed a ball bearing from the next experiment over.

We also had the old "drop a mercury thermometer down the sink" problem, although it wasn't as spectacular as when the same thing has happened (not at my school, but we had a supply teacher from the local university) with a lump of sodium. Sodium, as you may know, is kept in oil so that it doesn't react with moisture in the air. The oil takes until the sodium gets some way down the plumbing before it washes off, at which point the repairs are a bit expensive. People in my school also had fun using a gas tap as a flame thrower, and seeing how far they could get water to go by attaching a bunsen burner to the water tap. Happy days. I don't believe I ever did anything particularly expensive myself, though. (I've fried a few thousand dollars' worth of kit in my business life, but it's not usually been my fault.)

Count me in the camp that thinks mercury concerns are overblown, but I still don't want beads going in my carpet :)

We have a fair few mercury thermometers still in service at work. Most are in research labs, but the upper level teaching labs request them also. We use to train the TAs in mercury clean-up, but for some reason that was written out of the curriculum so I'm the designated call person for a small mercury spill. I usually do 3-4 a year.

Our organic teaching labs have switched over entirely to mineral spirit based thermometer. The things are the bane of my existence as the columns break if you look at them cross-eyed, and unlike with mercury you can't shake them back down to rejoin the column. I'm only marginally successful with rejoining the column either by heating or cooling(both of which are endorsed). Cooling works better, but we don't keep dry ice on hand and liquid nitrogen will usually freeze the bulb and not actually rejoin the column...and usually cause the bulb to break. We've just conceded to buying ~40 fresh ones every semester(at ~$15/pop) and I'll piddle with fixing the broken columns when I get a chance.

I also keep some neat pieces in my office. I have a high end Beckmann calorimetry thermometer with a bulb about the size of my thumb that will read to a precision of .01ºC. Of course, I also have a nice Welch scientific manometer and a McLeod gauge-both of which I use with some regularity. Since I maintain some high-vac systems and don't implicitly trust ion gauges the way some folks are know to do, I always confirm-where possible-with a McLeod. Our environmental health and safety person has given up fighting me and just shakes her head when she looks in the case where I keep all that stuff in my office.

Possibly this is where I mention that I just bought an infrared thermometer on the cheap (although not, I suppose, $15) because my local electronics store (well, chain) is shutting down. I suspect I'm unlikely to break it. It's only good to 0.2ºC, though - is that good enough for students? I've generally discouraged my managers from looking too closely at my desk, which has an unused fridge, a load of bare lithium batteries for drones, drones, a hammer, surgical spirit... and a 30-pack of assorted button cells, just to be on topic. It strikes me that the odds of anyone needing all the types is quite minimal, so this is a pretty environmentally-unfriendly way of selling batteries. But they're also, now I check, best before 2014...

Now, to ruin a carpet, I'm reliably informed you want an egg. And an electric iron.

I use my IR thermometer all the time for automotive purposes, but IR thermos do have issues. One of the biggest things is that they are assuming that the part you're reading is a black body emitter. It's good enough for most things, but at the same time the reflectivity of the surface can make a noticeable difference. As an example, the radiator in my MG is painted flat black. Just for the sake of experimenting, I sanded one spot down to bare brass and then polished an even smaller area. I get about a 10ºF temperature spread depending on whether I point the laser at the painted area, the bare brass next to it, or the polished brass. The flat black reading is closest to what I get if I pull the radiator cap and actually put a thermometer in it(mercury, perish the thought), and honestly I consider it "close enough."

The big thing, though, is that for many applications you need to actually submerge the thermometer bulb. A good thermocouple works just as well as a glass thermometer(although the calibration can drift) although they have their own issues and one comparable in accuracy and precision to the glass thermometers we would buy is quite expensive-both for the thermocouple itself and for the control box. In my research lab, we had some fancy hotplates that had a thermocouple meant to be put down in an oil bath on the hotplate surface and then it would maintain a setpoint temperature, but those were mostly for if you wanted to bring the temperature to a specific point and not actually measure the temperature of something happening(of course, in many cases you were doing something "under reflux" meaning the solvent was boiling, and your maximum temperature of the reaction was governed by the boiling point of the solvent).

I'll also mention that in my first research lab, we used oil baths with about 20 feet of Nichrome wire coiled in the bottom and would connect them directly to a Variac(or Powerstat or other variable autotransformer, since I'm going to be pedantic about the fact that only some of the things we had in the lab were actual Variacs :) ). They would hold a steady temperature for days, and once I'd established the characteristics of a particular oil bath I'd mark commonly desired temperatures on the dial of the transformer and could just go right to that...at least until a condenser line popped off and I'd have to change the oil.

BTW, when I took organic chemistry, our first task was to calibrate our thermometers. My undergraduate school bought less expensive mercury-in-glass thermometers, and we would calibrate them by checking the melting point of known compounds. The error was not consistent, but instead varied based on the measured temperature. The professor's explanation was that the bore was inconsistent in size. In any case, we were expected to calibrate over a range of around 50º-200º C(with at least a half dozen points in between) and any reported temperatures had to be "corrected" values. It was typical to see a +/- 5º error at the worst, although +/-2º was typical and at some points any given thermometer would be dead on. The poor sap who broke their thermometer mid-semester had to go through this again.

Count me in the camp that thinks mercury concerns are overblown, but I still don't want beads going in my carpet :)

 

We have a fair few mercury thermometers still in service at work. Most are in research labs, but the upper level teaching labs request them also. We use to train the TAs in mercury clean-up, but for some reason that was written out of the curriculum so I'm the designated call person for a small mercury spill. I usually do 3-4 a year.

 

Our organic teaching labs have switched over entirely to mineral spirit based thermometer. The things are the bane of my existence as the columns break if you look at them cross-eyed, and unlike with mercury you can't shake them back down to rejoin the column. I'm only marginally successful with rejoining the column either by heating or cooling(both of which are endorsed). Cooling works better, but we don't keep dry ice on hand and liquid nitrogen will usually freeze the bulb and not actually rejoin the column...and usually cause the bulb to break. We've just conceded to buying ~40 fresh ones every semester(at ~$15/pop) and I'll piddle with fixing the broken columns when I get a chance.

 

I also keep some neat pieces in my office. I have a high end Beckmann calorimetry thermometer with a bulb about the size of my thumb that will read to a precision of .01ºC. Of course, I also have a nice Welch scientific manometer and a McLeod gauge-both of which I use with some regularity. Since I maintain some high-vac systems and don't implicitly trust ion gauges the way some folks are know to do, I always confirm-where possible-with a McLeod. Our environmental health and safety person has given up fighting me and just shakes her head when she looks in the case where I keep all that stuff in my office.

One question, can we count on meters being accurate that are decades old. I have a camera with a light meter that I know is off by 75%. Kodak says on most c41 you have a spread of 7 stops but I think 4 is more reliable.

I shoot Ektar 100 like it's slide film. You can probably get away with +2/-1, but I find that the film looks its best when dead on or at most maybe +1/2.

The Portra films are a lot more forgiving, but I don't have a huge amount of interest in low contrast, low saturation film. I'll throw in my obligatory mention of how much I miss 400UC-maybe I'll shoot a roll of it this weekend.

One question, can we count on meters being accurate that are decades old. I have a camera with a light meter that I know is off by 75%. Kodak says on most c41 you have a spread of 7 stops but I think 4 is more reliable.

No, you need to test it.

A Quick and Dirty test is, in broad daylight, does the meter give you an exposure reading consistent with the sunny 16 rule. f/16 at 1/ISO shutter speed, or f/16 at 1/250 sec for ISO 200. Or sunny 11 if you live where the sun is not as bright.

This does not test linearity, or if the meter components are working properly, just the exposure at ONE light level.

Some older cameras may have worn ring resistors, and the meter won't read properly as you adjust the aperture.

Count me in the camp that thinks mercury concerns are overblown, but I still don't want beads going in my carpet :)

 

 

I also keep some neat pieces in my office. I have a high end Beckmann calorimetry thermometer with a bulb about the size of my thumb that will read to a precision of .01ºC. Of course, I also have a nice Welch scientific manometer and a McLeod gauge-both of which I use with some regularity. Since I maintain some high-vac systems and don't implicitly trust ion gauges the way some folks are know to do, I always confirm-where possible-with a McLeod. Our environmental health and safety person has given up fighting me and just shakes her head when she looks in the case where I keep all that stuff in my office.

The McLeod gauge mention takes me back a ways.

The McLeod gauge mention takes me back a ways.

It's amazing how many people I know who work with Hi-Vac systems and have no idea what one is or laugh at the idea of using one.

Ion gauges are pretty darn good these days, but I was taught that they're basically useless unless calibrated. Our ancient MALDI-TOF depends on having good ion gauges to actually work properly, and not too long ago we had one burn out(they are, after all, basically a vacuum tube, and this one died when an idiot tried to turn in on at around 10^-1 torr). The replacement wouldn't read correctly and consequently wouldn't spin up the turbo pumps at all or at best would keep the speeds low on them and not ramp them as it wasn't seeing a proper pressure drop(the turbo pump controller also controls the ion gauges to avoid grenading the pumps). We pulled the service manual and it described ion gauge calibration...and required the use of a McLeod. They were glad I had one.

As a chemist, I can't help but weigh in on the mercury issue. Regarding the batteries, there is zero risk for the user - unless you break open the battery. The reason they were banned is that they present a significant environmental problem when the mercury ends up in a landfill. If you choose to use them - however obtained - it's important to make sure that does not happen, but dispose of them properly. Find some place that collects hazardous materials in your area, even if that's a bit of trouble.

As far as the dangers of mercury are concerned when you are exposed to the metal, the problem are mercury fumes. If you swallowed a lump of mercury, it would go straight through you and virtually none of it would be absorbed by the stomach. But a very small amount of it would evaporate in the process, and you would inhale it. The small inhaled amount is the problem.

If you had a whole glass full of mercury standing in your bedroom, the effect would also be quite small, because the surface area is comparatively small. If you break a thermometer and spill a small amount of mercury on the floor, and this floor would be an old wooden floor where the tiny mercury beads disappear in the cracks and can not be taken out, that is a much larger problem, because the combined surface area of the all the beads is very large, and hence there will be a lot more evaporated mercury in the air. If you spill mercury, don't run away to avoid contact. Make sure you mop up all drops - even the tiniest little one - and dispose of them properly. You can buy mercury spill sets that chemically bind the mercury and make it harmless. Get one if you work in a place where mercury thermometers are used regularly!

Compounds originating from metabolizing mercury pass the blood brain barrier easily, and cause brain damage. Symptoms of mercury poisoning include irritability and aggressiveness. There are anecdotes of an old physics professor at my university shooting down the hallway at his colleagues. After he passed away, his lab was renovated, and they found countless tiny mercury beads under the old wooden floor boards.

Last but not least, most mercury compounds are far more toxic than metallic mercury. In the old days, hats would be treated with mercury compounds as preservatives and fungicides. That's why the hatter is mad in Alice in Wonderland. The most toxic of all is Dimethylmercury. A couple of drops, not on her hand, but on her protective lab gloves, killed chemistry professor Karen Wetterhahn in 1997. Dimethylmercury is one of the metabolic products of metallic mercury.

As a chemist, I can't help but weigh in on the mercury issue. Regarding the batteries, there is zero risk for the user - unless you break open the battery. The reason they were banned is that they present a significant environmental problem when the mercury ends up in a landfill. If you choose to use them - however obtained - it's important to make sure that does not happen, but dispose of them properly. Find some place that collects hazardous materials in your area, even if that's a bit of trouble.

 

 

 

Last but not least, most mercury compounds are far more toxic than metallic mercury. In the old days, hats would be treated with mercury compounds as preservatives and fungicides. That's why the hatter is mad in Alice in Wonderland. The most toxic of all is Dimethylmercury. A couple of drops, not on her hand, but on her protective lab gloves, killed chemistry professor Karen Wetterhahn in 1997. Dimethylmercury is one of the metabolic products of metallic mercury.

And keeping it photographic, methylmercury was the cause of Chisso-Minimata Syndrome, famously documented by the great Gene Smith.