Is there a universal NIOSH definition of "inert"?

[rowland_mowrey]

Guys;

 

I searched my darkroom and found a set of microdensitometry test patterns. One is negative and one is positive, on lith film.

 

So, I could set up to do the exposures somehow. Measurement is now the problem. Unless we just publish the results and let people judge for themselves. I tried scanning and got a moire pattern as I expected. I'm going to try a few things before I give up on it though.

 

Ron Mowrey

[lex_jenkins]

First of all, I want to acknowledge the valuable information provided by Patrick, Ron and Kirk. You are all tremendous assets to these forums and I greatly appreciate your contributions.

 

As for these debates I believe they are healthy and make for lively, interesting and revealing reading as well as being of value for those photographers who enjoy the technical aspects of the craft as much as the artistic. I only ask that everyone continues to participate in a spirit of mutual respect.

 

My observations on this particular issue are limited to only a couple of areas:

 

First, as a former federal OSHA safety and health inspector, I can only say that the purpose of an MSDS (material safety data sheet, for folks unfamiliar with the terminology) are intended only to inform employers, employees, the transportation industry and emergency responders about the potential hazards associated with a chemical or other material.

 

Therefore "inert" within the context of an MSDS is not necessarily relevant to the issue of chemical purity for the sake of making consistent compounds.

 

NIOSH (National Institute for Occupational Safety and Health) is the research branch that conducts experiments and provides recommendations to enforcement agencies such as OSHA, MSHA (Mining Safety and Health Administration) and EPA. NIOSH is not a regulatory enforcement agency. They are the primary source of information used in the assembly of an MSDS. Again, the focus of NIOSH is safety and health, so their definition of "inert" does not necessarily apply to other disciplines of chemistry. Coincidentally, tho', in many cases the definitions would match because with many materials inert is inert, regardless of context or use.

 

For a definition of "inert" as it applies to the purity of chemistry from the standpoint of *application*, one would have to look to the organizations which NIOSH also uses for reference material. There are many and, frankly, this is beyond my area of expertise which was occupational safety and health.

 

My second and last observation is casually related to the discussions regarding volumetric measurements.

 

When I was younger and had steadier hands I participated in various target shooting sports. Because of the cost I began reloading my own ammunition. Over time I discovered that there was no practical or significant difference between the consistency achieved using ammunition into which gunpowder was carefully weighed using a powder trickler for each charge versus using Lee's yellow plastic powder dippers.

 

These dippers were relatively long and narrow - totally unlike a typical set of kitchen measuring spoons - and the design facilitated consistent results. Using the dippers involved simply dipping the measure into a bowl of gunpowder, tapping the handle to level off the overfill and pouring the powder into the brass cases. The trick was to develop consistency in leveling off the measures. For example, scraping off the rounded overfill using a flat edge was not good because it could compact the charge resulting in inconsistencies. A simple tap of one finger or sideways shake was best.

 

It sounds rather crude compared with weighing each charge yet differences between the two methods were insignificant. I got the same accuracy in grouping and my chronometer confirmed that both methods produced equal results.

 

The difference is that weighing charges required no skill whereas using the dippers required some skill to produce consistent results. This was especially true because gunpowders vary between large and small flakes, tiny BB shapes and shapes similar to broken pieces of pencil lead.

 

So my personal experience indicates that volumetric measurement is valid, otherwise I would not have risked blowing up my gun or myself if I believed the method was significantly inconsistent.

 

My experience mixing developers from scratch is extremely limited and only moderately successful. I hadn't even mastered the art of choosing compatible ingredients so I doubt that my use of kitchen measuring spoons was as significant a factor as my ineptitude at mixing coffee, lye, etc., into a workable solution.

 

Take with a dose of salts.

 

(BTW, the correct original expression, "dose of salts", refers to a dose of laxative. IOW, it means be careful taking advice because the advisor may be full of s__t.)

[anders_br_the]

I have been following these discussions for a while, and I found it funny that Lex brought up one aspect I have been thinking about too regarding volumetric measurements, the Lee dipper!

 

Gunpowder is rather uniform in consitency compared to many chemicals discussed in these trads, so i would say the comparison is not entirely valid. In measurements one refers to precision and accuracy as two different things. Precision is how close you come to the correct value, and accuracy is how close your measurements are in reltation to one another. Think about target shooting. Good precision is hitting the bullseye (your average point of impact is center). If you have good accuracy, you might not hit the center, but your shots are very close to one another.

 

For instance; i have a teaspoon that might differ from your teaspoon in shape and size (teaspoons are not standardized!) If we both are accurate about our measuring technique we may both have good accuracy, but we may not measure out the same amount! Think about it, it should be pretty obvious.

 

back to the Lee measure; it is supplied with instructions on how to measure, the Lee measure is standardized, and the charges it throw are conservative for safety reasons.

 

I am an active bench rest shooter myself (bench rest is all about extreme accuracy, the formula one of shooting sports) and the whole world elite and myself use volumetric measurement of the powder for reloading ammunition. Let me tell you, if it was found to give an advantage by weighing the powder, everyone would soon be doing it. We all still use powder measures for short range bench rest (out to 300 meters, long range shooters weigh... there it definitively matters for reasons not interesting to this forum).

 

I shold also inform you that i am an organic chemist, and for all my scientific and photographic work I weigh. I do not use teaspoons, rely on manufacturers packing and which crystalform whatever chemical is in. I weigh, often taking precautions to remove absorbed moisture etc.

 

So for me, which method I use depends on the intended purpose. If you want to experiment and KNOW what you are doing, you should weigh. Otherwise it is a qualified guess, not a known amount.

[kirk_keyes]

Ron - so no nondisclosure agreement. That's interesting...

 

Conrad - great minds think alike! Although if we did find someone with a microdensitometer, to use it would probably require a whole different level on our part in our testing procedures to get accurate and repeatable results from it. It also would mean that we would have to repeat tests on multiple occasions - all the sort of stuff that Ron could tell us about that go into testing a new developer. Perhaps that would be a good article or at least a new thread...

 

I looked over my Henry book last night and he had problems finding an actual microdensitometer and ended up adopting a Zeiss microscope, hoioking it up to a computer that controlled the position of the microscope stage, and a photo multiplier and a Zeiss data acquisition system to collect microdensitometery readings. I actually have a friend that does microchemical analyses and Zeiss and Nikon scopes are his primary tool. He also has a high-end digital camera connected to the scope. That may do it! I guess I need to check with Ron about the masks that he mentions below.

[kirk_keyes]

Patrick, I did look at the web page you provided and even looked around the glossary and the rest of the site some as well. (And I assume you looked at the ones I provided too). I'm still not convinced about this site having the "NIOSH Definition", and that site is not even NIOSH or US governement web site.

 

The site does not give a reference to any Code of Federal Register (CFR), where all goverment regulations are recorded. You may have noticed the US Department of Transportation definitions I gave above supplied CFR references.

 

Go to the home page of the web site you listed and you will see they would like to sell you the domain name to US$3450. And the link you give actually comes up trying to sell you a domain name for US$59 - that's not even a very good deal. I did find the pages you reference, but I had to find it through google. I know it is hard to find stuff on US governement site - the EPA site annoys the hell out of me sometimes. But this site is not an authoritative site.

[kirk_keyes]

Patrick, I'm familiar with your credentials, at least as far you've stated them in your PhotoTechniques articles. You are a retired aerospace engineer that worked with NACA/NASA. That's cool! If you would like to supply more info than that, I would like to hear it.

 

I'm also familiar with your articles - they are some of my favorite ones that I've read in PhotoTechniques.

 

I'm not on some personnal attack as I'm sure you are not as well, I just want claims to be supported by proper references. I think we have far too many unsubstantiated claims made for many things in these types of forums.

[kirk_keyes]

Lex - that's for giving your input on the proper uses of MSDS sheets.

 

You and Anders both mention that for high accuracy, long distance shooting that wieghing is the preferred method of measuring out gunpowder. I suspect that is precisely because it IS more accurate and the distance shooters need that extra accuracy. Small variations in the amount of charge probably do not have the time or distance to be very noticable when shooting at targets that are at shorter distances, but when long ranges are involved, and longer times of flight involved, it sounds like that variation does become noticable and thus wieghing becomes the preferred method. Is that correct?

 

So it is again when we are looking at the fine details that these affects become appearant - which is been the main contention that Ron and I have been making.

[rowland_mowrey]

Kirk;

 

The unsupported claims and myths are what started me as well. I want to have statements supported by facts.

 

My charts are resolution charts that can be adapted for microdensitometry.

 

My comments here and elsewhere about micro densitometry come from a chapter of Mees, "The Theory of the Photographic Process" called "The Structure of the Developed Image". He gives three definitions:

 

1. Sharpness is the property of a photographic material that leads to pictures having good screen definition. It is a subjective concept.

 

2. The term acutance is the objective measure of sharpness.

 

3. Resolving power is the maximum number of long parallel lines that can be distingushed separately and does not correlate well with sharpness.

 

Too many talk about 1 and 3, but not enough about 2. The actual response of a photographic material is subjective, but is always related to 2, and rank ordering by viewers of subject material always results in following the values calculated by 2.

 

He also shows values of density that vary from 1.7 in 1 micron lines down to 1.4 in 100 micron lines at identical light intensity and time, showing the change in curve shape due to edge effects or the micro contrast of a subject material. Included are the effects of contrast on subjective and objective evaluation of all 3 above.

 

Kirk, I did have an agreement with EK. It expired a few years back, after I retired. Now, non-disclosure is really an ethical issue with me. I know that some would argue this point with me, but I won't change. I will not disclose proprietary formulas. I can give general suggestions, but not precise information.

 

I would like to direct you all to a similar thread by James Dainis on color over and under exposures. Fascinating, as Spock would say.

 

I too load my own shells using volumetric measurments. I'm not a bad shot but am deteriorating due to eyesight and tremor. I use volumetric backed up by quality checks using a powder balance. That insures uniformity. I have my Lee dippers calibrated for all forms and types of powder I use for rifle, shotgun, and pistol. The difference is that, as pointed out above, powders are uniform, and therefore errors in volumetric measure are small. If you look at velocity tables, you will see that there is a range of powder rates associated with a given powder in each book such as those by Lyman and Lee. None of the books I have read seem to agree on velocity vs powder measure. I stick to one powder, at one rate, and one bullet weight, for a given calibre and do pretty good.

 

Regards.

 

Ron Mowrey

[kelly_flanigan1]

Here I use .44 lead balls; blackpowder; patches; and measured by the volume loads. Fooling with different patch lubricants and patch thickeness is a huge variable. What is all this reloading of brass for?:)

[patrick_gainer]

Let me take what I hope is a different tack. It has been expressed by at least one other in this thread that there is no point in spending money for analytical grade of any chemical if you know that a lesser grade will suffice. we have heard that for at least one emulsion-developer combination guarded by trade secret that a miniscule amount of chloride will ruin a batch of results. We have seen that an assumption of anhydrous when pentahydrate was intended caused a problem.

 

If the problem with chloride content exists with a secret, how are we to know to avoid it? I rather imagine that if it is made available to you and me, it will be as a combination anyway. We won't even be tempted to duplicate the results by teaspoon measurement of tech or commercial grade chemicals.

 

Chlorine content of water will use up a considerable amount of ascorbic acid or its isomer, as will dissolved or entrained oxygen. In any of the developers I have proposed, these are things to look out for. It takes a lot of chloride to change the characteristics of a film developer. Trace amounts will not do. So what are we who do film and chlorobromide papers worried about? Nevertheless, I never advised any one NOT to weigh chemicals.

 

If we agree that we do not know the precise assay of the sodium carbonate in pHPlus or other commercial grade, how much more likely are we to know that it is not exactly the same as we buy for photo grade when the precise assay of that grade is not made known?

 

If we want to argue, let us argue about proper means of testing that we might use in our own darkrooms (or kitchens). It seems that many of us are not inclined to trust NIOSH specs or any others. In that case, it is pointless to weigh out milligrams of a chemical when we do not even know what it is. It seems that I am digressing again, but read on.

 

My background is 70 years old and will take quite a few words just to hit the high and low points. I always had an interest in the physical world and the metaphysical world. I studied chemical engineering for 3 years, then switched to aeronautical engineering. All the time, I was an amateur photographer and an oboist of sufficient ability to be first oboist of the University-Community Orchestra and later of the Peninsula Symphony of Newport News, VA and of the Norfolk Symphony of VA which later merged to form the Virginia Symphony. Upon graduation with BS in Aeronautical Engineering, I was employed by NACA at Langley Research Ceter to do analysis of flight test data among other things. Without moving from that desk, I later became employed by NASA. One of my first tasks was to design star charts for use by Mercury astronauts as emergency reference for reentry alignment. By the time of my retirement in 1982, I was doing human factors (see "Cheaper by the Dozen") research into piloting tasks. When I retired, my position statement described me as "an internationally known expert in non-linear mathematical modeling of the human operator." Go figure. We did what had to be done. Our group assigned to any project might have mechanical, electrical and aeronautical engineers, mathmeticians, physicists and anyone else who might be needed. We learned to talk to each other.

 

Now if we are concerned about the subject at hand, which is how to know what we need and how to know if we've got it, my tendency would be to have a task group of varied experience to work on it. I know the old saw about things formed by committee. This is not a case of voting to accept opinions, but of finding facts and making them known.

 

We have the problem of not being in personal contact with each other. That is a valuable condition. Many things that are written have a much different context than the same things spoken face to face. You and I cannot see when the other is smiling or frowning. Believe me, I enjoy smiling much more than frowning.

 

Enough. maybe too much.

[kelly_flanigan1]

LEX and the group Re: <i>Therefore "inert" within the context of an MSDS is not necessarily relevant to the issue of chemical purity for the sake of making consistent compounds.</i><BR><BR>The MSDS sheets can have other things besides chemicals. The MSDS sheets for lamination film has NO chemical warnings; BUT it lists one big problem; busting ones rear on the CLEAR scraps of finished hot lam film; that miss the trash can. One can slip and fall real bad on the clear scrap; which is generated in the course of business at a print shop; school; photo lab. When one is laminating several hundred feet of film a day; one lone scrap the size of a credit card will cause an person to fall.

[kelly_flanigan1]

In read write heads; the slider/heads are cut out of wafers; made up of layers; like an IC chip. If some of the purity of the solutions used in plating is too low; the head can degrade with time; but pass all specs when made. This time bomb causes the heads to drop in performance; and is abit rare. Once we had a major customer who had data rot; and we traced it back to the certain wayers used by vendor B. What a mess.

[conrad_hoffman]

There seem to be a lot of shooters here, myself included. Advice of the day- If you're going to carry a gun and a camera, double check to be sure you've grabbed the right tool for the job at hand!

[rowland_mowrey]

Kelly;

 

In certain read write heads, the laminates are embedded in ceramic. The cermaic for a certain company had a very tight spec, but didn't include entrained air bubbles. As the head wore, the ceramic did too, and the bubbles were exposed and became 'ice cream scoops' as far as the diskette was concerned.

 

In double headed drives, this scooped out the medium right down to the transparent support. The manfufacturer learned a hard lesson.

 

Patrick;

 

I agree, lots of things cause lots of problems, for example ozone in some European municipal water systems will consume ascorbic acid differntly than chlorine in US water systems. Varying pH of water systems also affect solutions. You say that one formula that is proprietary and therefore not hand mixed may have a problem.

 

Well, here is an answer. In my short tenure here, I have seen at least two references to hand mix formulas on other sites for this developer, both wrong, btw. In recent months, several people have made reference to this particular formula and the fact that they were hand mixing it. If they had used your method, using swimming pool chemistry, and if Kirk Keyes comments about NaCl impurity was correct, then they would have problems with the formula.

 

I never said that anyone should stop using the methods or chemicals that they were using. I just pointed out the potential faults and problems inherent in some methodology and useage. Kirk and others have done the same. I repeat here, if it works for you, use it, if you are satisfied, keep doing what you are doing. If you read my posts here and elsewhere, I have said this repeatedly.

 

Just as you have stated, and I paraphrase, others are misquoting me and attributing statements to me telling me what I said and meant. What I said and meant can only be derived from what I write.

 

I added however, that our current 'eyeball' methods of evaluation were sometimes inadequate to the task of determining the quality of our results in photography. I added though, that if you like it, then that is sufficient. My reference to Mees describes some of the pitfalls though that escape us in qualitative measurments.

 

I have not even delved into the tanning effects on gelatin by certain developers, the cracking effects that degrade images using some developers, and etc. This is a huge area involving complex interactions.

 

I would not think of giving you advice on deriving star charts. Just please give Kirk and me for that matter, and some of the others who are chemists and photographic engineers the benefit of a doubt when we give advice on potential problems.

 

While you were deriving those star charts, I was at Cape Canaveral telling the astronauts how to take pictures at high altitude and in space, and giving them the UV filters to use with their cameras.

 

While you were working for NACA, I was flying high altitude intelligence gathering missions in the back seat of jets as well as working on the ground. I was certified to fly up to 100,000 ft, hence my UV filter knowledge. I also carried a rifle and pistol when the situation warranted it, and I lost two men under me. I have great respect for human life, having lost two young men who worked for me.

 

All of us, when we reach this age (I'm just slightly younger than you) have great respect for the wisdom of others, and should respect the fact that others may have knowledge that we do not and that we can learn from and profit from. Kirk is teaching me a lot I never knew, but just had as qualitative information. I cannot presume to teach him in his area of expertise. I do listen to his advice. Same with Lex.

 

OTOH, I cannot just dig into my personal cache of proprietary prints or data and throw them out here. In the first place, that cache of prints and data were the property of EK and were left behind. All I can do now is either repeat them personally and post them, or tell you general facts about my old data. Also, I must draw on my color experience as that represents over 80% of my work. However, the analogy to B&W is there, and I can draw on it to point out possible problem areas.

 

Warmest regards to you all, and thanks for the very good contributions.

 

Ron Mowrey

[patrick_gainer]

Well, Ron, if you are talking about the Mercury, I must say I was sitting at my desk wondering why in the world they were trying to take UV photos through the Mercury window when the UV spectrum that came through was not as broad as what we see on a clear night. They had special lenses that passed all the UV that you could want, but none of it got to the lenses. They could not see any stars of magnitude >6.

 

Some of these things were funny. Others were not. When Scot Carpenter came to inspect the star charts, he couldn't resist sliding down our wide banister on his way out. When he used up almost all of his maneuvering fuel gawking, that was not funny.

 

I still haven't seen a response to the question "How do we know what purity we want, and how do we know when we've got it?" I see Arm&Hammer baking soda, specified USP, cheap as dirt. It would be cheaper to heat that into the carbonate than to buy so-called photo grade of unspecified purity. But do we need to go to that trouble?

[kelly_flanigan1]

Ron; I was given the task once of how quickly to destroy a hard disk drive's contents. At that time; computers were disassembled; and the actual disk platters shredded in a aluminum chipper. One method is just to fry the thing in a oven; above the curie temp of the platters magnetics. The plastics and no metal parts creat a mess. Certain chemicals quickly mess up the platters; and do the job quicker. Coated disks create a problem; sometime a crusher is the easier; cheaper method.

[rowland_mowrey]

Patrick;

 

You misunderstood, I think. The Astronauts were taking color pictures out of the capsule window, not UV pictures. They wanted to filter out the UV and they wanted to have information on the EK UV series of filters which I used to use in high altitude photography.

 

At that high altitude, UV radiation is significant even through their window. At least that is what NASA told us. EK designed a film with thin support for the flight so that they got more exposures / roll as well, and the film was tested in vacuum to determine if evaporation of residual solvents caused any problems. I worked with both EK and NASA at that time in my position at CCMTA.

 

As for your answer on sodium carbonate, or indeed any chemical, I use photographic grade. I stated that in the original thread, and I rely on the distributor to supply me with such chemicals. If they don't, the onus is on them to make amends with me. So far, they have not let me down. Now, they may very well be supplying me with soda ash, and by Kirk's definition I may be getting floor sweepings, but that is between me and them if I should have a problem.

 

Kelly, at EK we used observed crushing for hard disk drives containing confidential data. IBM honored their warranty on drives if we returned a crushed disk drive to them for warranty replacement as long as the IBM serial # was left intact on an uncrushed surface of the drive. I was the research member of the EK team that helped negotiate that little detail.

 

We had a joint computer security task force that met on a regular basis at EK or at IBM Rochester HQ.

 

Ron Mowrey

[kirk_keyes]

Ron, Patrick,

 

I do have some suggestions about making your own carbonate out of bicarbonate, but I have to go to sleep now and then it's off to the historic races tomorrow so I'll probably have to wait until Monday to make them.

 

By the way, I was in the first grade when Niel Armstrong stepped onto the moon, so I envey both of your involvment in the space program. I'm just a 41 year-old analytical chemist that had the extreme good luck to start out in a lab the did specialty testing and I ended up being the guy that got to research methods and then do all the odd-ball samples that came in for about 4.5 years. It was an excellent way to begin a career as an analytical chemist.

 

Patrick, did you work on the charts with the 3 famous stars Navi, Dnoces, and Regor on them? I know that was Apollo, but if you were involed with that I'd love to hear about anything that you would like to comment on!

[patrick_gainer]

Ron,

I didn't really think you would have been involved with that mess, but it did happen. Whoever at NASA told you there was significant UV getting through the window had not studied the matter. The window was IIRC about 1/2 inch of window glass, albeit high quality. The transmission density of it was actually measured to be about the same as the atmosphere. We had to know that for our star charts. There might have been enough UV getting through to upset color balance, but someone else (I know not who) designed and had built a special Hassy with a lens specifically designed to transmit and focus UV, thinking that here was a chance to photograph a part of the spectrum we cannot see down here. While it is true that they were above essentially all the atmosphere, the window negated all the expense and effort that went into the camera. It was not until Gemini and EVA that they could use it. I think the lens was constructed of Germanium glass, but won't swear to it.

 

As to what stars were on the charts, it depended on what part of the sky would be visible within +- 20 degrees of the orbital path. My job was to set up transformation equations from Nautical Ephemeris tables of right ascension and declination to orbital path coordinates. I had plenty of help entering data from the ephemeris, programming the equations, and plotting the charts. A genius in the analytical computing division used the high speed line printer to print symmetrical characters (o, x etc) where stars should be on very wide paper. Our office people put black circles over these characters of size according to star magnitude. There was a different chart for each possible 15 minute launch window. The large charts were reduced and printed on special plastic and equipped with a time scale and a cursor that showed the outline of the Mercury window to scale. When the cursor was aligned with the time scale at time after launch, the cursor showed the star pattern that should be seen in the actual window if the capsule was properly oriented for reentry, with sufficient accuracy to pervent burning up.

 

We could do that whole task up to the final construction with the personal computer and printer I have in front of me. We still had electromechanical calculators for matrix manipulations. There are other stories about that.

[kelly_flanigan1]

Quartz glass is sometimes used to pass UV; in bulbs; lenses; cylinders in UV printers; etc.

[rowland_mowrey]

Our high altitude cameras looked out through glass windows that were transparent to UV, and the higher we went, the more filtration we needed to eliminate the UV blue shift and haze. EK made a series of special filters that went above the normal UV series 1 and 2. They supplied us with a 3 and 4 filter set for 50,000 ft and 100,000 ft. I talked to two of the astronauts about this as they were concerned that on the first flights the pictures were too blue due to UV and had too much haze, and wanted to know how we did it with high altitude photos. That is when I was called in to talk to them and bring them filters.

 

Every can of Aerial Ektachrome was supplied with a package of filters in the can to fit over the lens of our camera. I still have one unused set.

 

The person who did the camera work was Roland (Red) Williams. I have a picture of him with the astronauts with the Hassy, and another picture of him with me in front of Liberty Bell 7, with Glenn's capsule in the background. My mother cut the picture of Red with the astronauts out of the newspaper and sent it to me, the other one was taken of us about the same time as the newsphoto was taken. They didn't publish the photo of us though. I wasn't news, so they gave it to me.

 

I have a little box of discarded parts from Red that failed to pass muster for the Hassy. The film advance was not right for the glove, etc, etc. Red would machine them out of aluminum and replace parts with the lighter weight stuff. He replaced stainless screws with aluminum screws and drilled holes in the frame of the camera to lighten it up.

 

 

Ron Mowrey

[patrick_gainer]

I should mention that I was never officially a member of the Space Task Group that started at NASA Langley Research Center. Somebody recommended me to Robert Voas, a human factors type and head of the group, for the star chart job. I had a chance later to relocate to Houston, where many of my friends had gone, but decided I had too many interesting things to do in Virginia.

 

I never met Red Williams, and don't know if his project involved intentionally photographing in the UV. From what you say, Ron, it may have been another project, and it may in fact never have lifted off if they tried to take UV photos through the capsule window on the ground. I can't imagine anyone of us designing a camera specifically to record UV images and then putting a 1/2" thick piece of flint or crown glass in front of it. As I said, we found that stars dimmer than 6th magnitude would not be suitable for the star charts because the window would not let them be seen. I seem to remember that the optical density of that window was about 0.4.

[rowland_mowrey]

Patrick;

 

No one ever mentioned in any way photographing in the UV. All they talked about were taking color photographs through the capsule window.

 

They took several rolls of 120 film on thin support and all of the astronauts took pictures from orbit using the then existing color negative film. I have no idea whether they ever used the filters that I gave them. I only got involved in that part of it after about the first 2 manned launches, although I worked on all of them until I left in August of '62. Our crew was the last to sign out of the gatehouse at the pad for Glenn's launch, and we were the first to sign back in.

 

The cameras that I saw had normal lenses, but had vastly altered bodies due to new winders, focusing rings, and lighter weight chassis / body with holes in it.

 

Ron Mowrey<div></div>