Teaspoon measuring

[ronlamarsh]

Hi all my chart does not include ammonium chloride or sodium citrate does anyone out there have the gram equivalent data for these chemicals i.e. grams/teaspoon ???? Thanks

 

[Bruce Watson]

Hi all my chart does not include ammonium chloride or sodium citrate does anyone out there have the gram equivalent data for these chemicals i.e. grams/teaspoon ???? Thanks

One is an indicator of mass, the other is an indicator of physical volume. Those two concepts are not the same thing. At all.

If you want to be consistent, buy a scale. Accurate scales for darkroom work aren't that expensive, and the precision of your darkroom work will improve considerably. Just sayin'.

 

[Sirius Glass]

I believe that the OP wants a chart with the weight in grams.

Steve

 

[Robert Hall]

The problem is that many chems are hygroscopic. The gain water weight as the get older. (Sounds familiar ) That means the amounts will be all over the place because you have no real starting point.

Scales are cheap, $50 will get you a great scale. Get one that weighs in .1 or tenth grams. Trust me, you will be very happy you did.

 

[Photo Engineer]

Using teaspoon measurements can result in an error factor of as much as 20% or +/- 10% from batch to batch of chemical based on the fineness of the crystals in a given batch.

If you can accept that much variation in your formulas, go right ahead.

PE

 

[sanking]

One is an indicator of mass, the other is an indicator of physical volume. Those two concepts are not the same thing. At all.

If you want to be consistent, buy a scale. Accurate scales for darkroom work aren't that expensive, and the precision of your darkroom work will improve considerably. Just sayin'.

I agree with Bruce. Why measure with a teaspoon when the cost of accurate scales is so inexpensive.

Have a look here, for example. http://www.balances.com/

Sandy King

 

[fotch]

I have purchase several analog Ohaus scales used of of epay, never more than $15-20 including shipping. I know the electronic are easier to use but they will not last as long. I also would worry about accuracy with the cheap ones.

 

[gainer]

One is an indicator of mass, the other is an indicator of physical volume. Those two concepts are not the same thing. At all.

If you want to be consistent, buy a scale. Accurate scales for darkroom work aren't that expensive, and the precision of your darkroom work will improve considerably. Just sayin'.

The argument of hygroscopicity is an argument against the consistency of weight measurements. The concepts of mass and volume are connected by the concept of density. Every time you measure both mass and volume, you can compute density. If you know density and measure volume, you can compute weight. That said, let me remind you that the computation of density to a certain number of significant figures can be accomplished accurately by the use of volume and weight measuring devices of much less precision if large enough quantities are measured, so that the ratio of mass or volume to precision of those measurements is as desired. I explained all this in my article of 1973, "Kitchen Tested Soups", in Petersen's Photographic. That being done, then smaller amounts of mass can be determined by use of appropriately precise volumetric measurements. In the case of hygroscopic chemicals, the best bet is a solution saturated at a temperature lower than your normal lab temperature.

If we were rich as Croesus, we might purchase only chemicals of reagent grade and weigh them to the fraction of a milligram. We would be foolish to do so without first ascertaining whether such precision is necessary for our purposes. Every solution we make for the processing of B&W film has some tolerance for error in measurement or quality of its ingredients. When you are prepared to tell me what those tolerances are, we can argue some more about efficient ways to achieve them.

PE is by former employment and current avocation and, for that matter, business, a laboratory research chemist. Here, the shoe is on the other foot. You don't know what you have unless you know your ingredients. Still, a mixture that depends on reagent grade chemicals and labaratory precision of measurements may cost more to produce than customers will pay, so it is worthwhile to do an analysis of sensitivity to variance in measurement and quality of ingredients.

Would you believe that every time I have mixed 1/8 tsp Metol, 1/2 tsp ascorbic acid, and 1 tsp sodium carbonate in a quart of water since 1973 the solution has given me the same activity?

 

[BradS]

classic....the scientist vs the engineers.

For whatever it is worth any engineer worth his salt will immediately point out that a product or process that is not robust against minor variations is worthless...or simply put, un-economic, not feasible.

and... sheesh! guys, the OP asked a simple question....and all but one jumped on him for measuring his chems with a teaspoon. Nice. What a nice bunch of helpful folks....:rolleyes:

For the OP, I looked up the density of Ammonium cloride and found it to be, 1.5274 g/ml . I figure a standard teaspoon is 5ml so, I get 7.6 grams per teaspoon. In a similar fashion, I get 8.5 grams per teaspoon for sodium citrate.

 

[Photo Engineer]

Brad;

You are right.....

Of course, if we don't pass things on correctly to the following generations, they are doomed to doing it incorrectly and this level of accuracy will slowly degenerat. So, what would you do if you were me? Would you teach the wrong things? Give inaccurate formulas? I am trying to teach, and others seem to not care. This is a tough position to be in for me. Especially when Patrick says that "since 1973 the solution has given me the same activity" when in fact, he may be using the same batch of chemicals or he may not have made exact side-by-side comparisons. IDK.

If you use the same ingredients from the same bottle with the same crystal habit, this method will work, but if you change batches or crystal size or habit, then the volumetric measures can be off by 20%.

Now, tell me, what would you say in my place?

PE

 

[archphoto]

Were measurements in teaspoons inacurate to begin with ?
I never understood that system anyway, it is like my coocking: a bit of this, a splash of that and no accarucy at all, not needed.

Would it not be wise just to weigh your chemicals in solid forms ?
In that way you have at least a standard and something you can repeat.

Keeping your chem's under a tight lid ofcourse in order to keep the water content as constant as posible.

Peter

 

[fotch]

I think the way PE is teaching is correct. If a recipe calls for 12 grams, it means 12 grams, not about 12 grams, or approximately 12 grams, or between 10 and 14 grams.

The more variables you induce, the harder it would be to find an error. Of course, it may work, just as an exposure is off a bit and the picture still is OK. Then again, maybe it isn't exactly what you expected, then tracking down the problem get harder with the more variables.

But then, what do I know. I just follow the instructions, seems much easier, at least for me.

 

[dancqu]

Hi all my chart does not include ammonium chloride or sodium
citrate does anyone out there have the gram equivalent data
for these chemicals i.e. grams/teaspoon ???? Thanks

I believe both chemicals have long term stability in solution.
So, as an alternative, mix up some easily weighable amounts
of each then dissolve in an appropriate amount of water.
Bottle then measure out the amount needed when
needed. Dan

 

[gainer]

Brad;

You are right.....

Of course, if we don't pass things on correctly to the following generations, they are doomed to doing it incorrectly and this level of accuracy will slowly degenerat. So, what would you do if you were me? Would you teach the wrong things? Give inaccurate formulas? I am trying to teach, and others seem to not care. This is a tough position to be in for me. Especially when Patrick says that "since 1973 the solution has given me the same activity" when in fact, he may be using the same batch of chemicals or he may not have made exact side-by-side comparisons. IDK.

If you use the same ingredients from the same bottle with the same crystal habit, this method will work, but if you change batches or crystal size or habit, then the volumetric measures can be off by 20%.

Now, tell me, what would you say in my place?

PE

I took your position in my previous post, and am certainly sympathetic. But I also took the position of the person who must make the results of the lab chemist practical as well as marketable. The results I spoke of getting with the simple volumetric measurements were from many different batches of Metol and carbonate. Ascorbic acid for use as Vitamin C has always been consistently 4 grams/tsp. It is that way because doses are prescribed in teaspoons or fractions thereof. The same goes for sodium bicarbonate. If I buy a pound of a chemical and trust the merchant to give me accurate weight, I can compute the weight of a fluid ounce or 30 ml or whatever volume from the measured volume of the pound I bought. I could as well measure the total weight, just to check up on my merchant, but I wouldn't have to measure it to the milligram.

I am not in your position. Neither are most of us who want to photograph something in B&W. I could not tell from the way one negative prints whether the developer I used to make it was exactly the same as the one I used to make another negative, even if the scenes were identical in everything but brightness range. Should I do the characteristic curve each time? How do I know that the film is not from different batches? There are and always have been ways to compensate for differences in film development during printing. My grandfather, who died in 1905, left a treasure of glass negatives, of which I have been able to print over 100 by various means. "By hook or by crook" as we old timers used to say.

 

[Photo Engineer]

Patrick;

If I were to begin teaching a form of engineering, which from your POV was slapdash and inaccurate, I would imagine you would come down on me hard. Especially if we were both in similar teaching positions as we are on APUG. However, the reverse is now currently the case and I am stuck with you teaching what is from my POV, slapdash chemical techniques in the lab. They work, to an extent, but may fail.

IDK what to do. I am in a dilemma here. The more I argue for what is right from a scientific POV, the more you "disprove" me with your results which rarely have checks and balances. Of course, you will win because your way is cheaper and easier. Who wants to do it the hard way even if it is right?

So, ask yourself, is this the legacy you wish to pass on to future generations. I will be dammned before I pass on anything that is not right, procedurally or otherwise for lab work. And, I would not work in a chemical lab with you if someone paid me big bucks. I want to live! I think that you might be a hazard in the lab and your own kitchen.

Sorry for the rant, but remember that you are not a chemist and I am not a mechanical or aeronautical engineer. These fields are far apart. How would you like an orthopedic specialist in ankles and feet doing brain surgery on a loved one? I know. From your POV you would say "they are both surgeons". I cannot accpet that philosophy.

PE

 

[gainer]

I think the way PE is teaching is correct. If a recipe calls for 12 grams, it means 12 grams, not about 12 grams, or approximately 12 grams, or between 10 and 14 grams.


But then, what do I know. I just follow the instructions, seems much easier, at least for me.

According to standard engineering practise, 12 literally means any number that round to 12 by standard rules for rounding, or greater than 11.5 and less than 12.5. If I want to specify 12 to the milligram, I say 12.000.

 

[fotch]

Well, then we know why products sometimes are a real nightmare. I have a friend who is an engineer and sometimes I will make something out of wood per his design.

If I understand what you just said, for example, the engineer request from me a wood block, 12 inches by 12 inches by 12 inches, and I delivered a woodl block 11.5 inches by 12.5 inches by 11.90 inches, its OK?

As they say, size matters.

I could not build a house or a cabinet or a clock!

But you could build an airplane? There must be something being lost in the translation or I am never going to fly again.

I certainly am not trying to insult you but it just seems screwy to me.

Ha, but then again, I am not an engineer.

 

[Photo Engineer]

Patrick;

I've been thinking about this and I have some additional thoughts.

In the few chemistry lab courses you took did they ever teach you to measure solids in spoonsful? Or, did they teach you to use weight? The use of volume to measure solids dates to the medieval alchemists who often did this, but the method was recognized for the unscientific method that it was, as scientists in general began adopting the scientific method.

If you realized that we experienced people are in a world wide classroom, and it behooves us to pass on the very best, then you might see things differently. We must teach the very best to those that follow or we will allow them to fall into error or allow them to fail utterly in keeping the legacy of analog photography alive.

I am totally frustrated at this moment, having been unsuccesful in convincing you that although your method may work, it may fail as well and it is the wrong thing to teach future generations. We have argued this on-line for quite some time and you are adamant.

My position is not adamantine in nature, but merely following the scientific method laid down many years ago as the medieveal scientists came out of that era, shrugged off the cloud of superstition and guesswork and adopted the right way of looking at the universe.

PE

 

[jim appleyard]

After reading all this, the OP has gone digital.

 

[Photo Engineer]

Nope, he moved to Photo Net.

However, Jim, having now chimed in...

What would you do if you were me?

I'm interested.

PE

 

[Nicholas Lindan]

12 literally means any number that round to 12 by standard rules for rounding, or greater than 11.5 and less than 12.5. If I want to specify 12 to the milligram, I say 12.000.

Here, here.

There is a tendency to anal retentivity in technical hobbies - and in all the wrong places.

With variations in scene contrast, uncontrolled lighting, shutters and apertures (how many here use T-Stops?) that are rarely better than 25% in accuracy, light meters that add their own 25%/1/4 stop error - and then add the variation in metering technique and a whole stop or two in preference in how dark a print should be made, and exposing at some 'personal ei' and mucking with developing times for 'N-1' and pulling an agitation regime from thin air - worrying about a gram or two of S. Sulfite makes no sense.

If you look at recipes for classic developers - as they came from the source - you will find many old formulas have been converted from ounces and grains to grams: an awful lot of things use multiples of 30 grams - meaning the original formulation was "Ah, heck, throw in 2 ounces and see how that works" - if it worked it got handed down as 60 grams. A recipe converted by an idiot will specify 56.7 gms - (N.B. the 60gm recipes are all 3.3010 gms in error). In real life any variation from 45 to 75 grams won't be noticed and might help. Weighing Sulfite out to 60.0 +/1 0.1 gram is most assuredly the wrong amount - as if it were to be titrated to the best value it would be a number like 67.3 gms, not 60 or 80 or 100. The one thing one can be sure about is that 60.0 gms is not the optimum value, it was just what worked well enough.

The sheet to sheet variation in paper speed and contrast is greater than any variation due to compounding developers with a teaspoon. Get thee a densitometer and weep.

Photography is an art. Touchy-feely is allowed. One doesn't need to buy a Holga to let go ... measure out chemicals by the 'pinch' or by pouring an amount into your hand - let the random element in without wasting $60 on a $10 toy.

If anyone wants to debate anal retentive credentials don't forget I'm the one here who advocates measuring enlarging exposure to 1/100th of a stop...

 

[gainer]

Patrick;

If I were to begin teaching a form of engineering, which from your POV was slapdash and inaccurate, I would imagine you would come down on me hard. Especially if we were both in similar teaching positions as we are on APUG. However, the reverse is now currently the case and I am stuck with you teaching what is from my POV, slapdash chemical techniques in the lab. They work, to an extent, but may fail.

IDK what to do. I am in a dilemma here. The more I argue for what is right from a scientific POV, the more you "disprove" me with your results which rarely have checks and balances. Of course, you will win because your way is cheaper and easier. Who wants to do it the hard way even if it is right?

So, ask yourself, is this the legacy you wish to pass on to future generations. I will be dammned before I pass on anything that is not right, procedurally or otherwise for lab work. And, I would not work in a chemical lab with you if someone paid me big bucks. I want to live! I think that you might be a hazard in the lab and your own kitchen.

Sorry for the rant, but remember that you are not a chemist and I am not a mechanical or aeronautical engineer. These fields are far apart. How would you like an orthopedic specialist in ankles and feet doing brain surgery on a loved one? I know. From your POV you would say "they are both surgeons". I cannot accpet that philosophy.

PE

If you and I were working side by side as research chemists, you and I would see things pretty much the same way. The only time I came close to injuring myself in analytical chemistry in college was the time I tried to blow some glacial acetic acid out of the jug after the lab assistant (who should have known better) filled the jug so that the blow tube was below the level of the acid. When I let up the pressure, I got a mouthful of the acid. That was VERY uncomfortable.

My career as aeronautical engineer was spent mostly in mathematical analysis of flight research data to obtain probable values of certain coefficients in the equations of motion by least-squares analysis. I learned a good bit about experimental error, both random and systematic.

I'm sorry, but I cannot see where anything I have written or taught, other than how to play the Oboe and make reeds for "The ill wind that nobody blows good", does anything but supplement what you teach, if indeed our paths even come close to crossing. I am not teaching Photo Lab, nor am I pretending to. You still have not read "Kitchen Tested Soups." I can tell. You do not realize that what I proposed was not slapdash, but was quite systematic. I did a sensitivity test on the main ingredients of D-76 to see how far off one could be and still get comparable results. I did a statistical analysis of weights of teaspoons of the commonly used chemicals. I described how to determine the weight per unit volume of bulk chemicals, and noted that these determinations should be repeated with each new batch. There were no cheap scales or balances in 1973 compared to the average wage.

Even if you have a scale or balance of sufficient accuracy and precision, the teaspoons help to use it by getting close to the desired weight. Why all the furor?

 

[Nicholas Lindan]

If I understand what you just said, for example, the engineer request from me a wood block, 12 inches by 12 inches by 12 inches, and I delivered a woodl block 11.5 inches by 12.5 inches by 11.90 inches, its OK?

Absolutely. And there isn't an engineer who will tell you otherwise.

If the wood block needed to be more precise then the dimensions would be specified 12.0 x 12.0 x 12.0 and any dimension from 11.9 to 12.1 would be acceptable.

If you look at an engineering drawing you will find they all specify tolerances. Usually the tolerance is implied by the number of decimal places used in the dimension. If it is a critical dimension it may be specified as, say 12.354 -0.000/+0.001 inches. Any dimension without a tolerance is suspect.

Ha, but then again, I am not an engineer.

I am one. Patrick Gainer is another.

Here is an engineering specification for the most bog-standard of all electronic components:

http://www.yageo.com/pdf/yageo/Leaded-R_CFR_2008.pdf

Notice that every number has a tolerance. Most of the data sheet is about how a 1K 5% resistor _isn't_ a 1K 5% resistor - initial tolerance, drift over time, drift with temperature, inductive effects ...

When a developer formula comes out with:

Metol 98%, <0.2% paraminophosphasomehingorother 12.3 gm +/ 0.15gm
S. Sulfite anhydrous, 90.60 · TC 42.6 ISO 418:2001 34 gm +/ 2.0 gm
Hydroquinone blahblahblah 2gm +/- 0.5gm

Then it is time to get out a balance and treat the numbers seriously. And the numbers won't come from chemists, but from chemical engineers. Until then it's all so much hot air.

 

[Venchka]

You know, the late Barry Thornton put forth the "two teaspoons of sodium sulfite" theory of film developing. The very much alive Ken Lee put forth the "two teaspoons of sodium sulfite" hypo clearing theory.

I can measure two teaspoons consistently. I could also weigh two teaspoons of sodium sulfite on my OHAUS balance scale or my digital scale. Anyway you cut it, it's still two teaspoons.

 

[Photo Engineer]

Nicholas;

This:

"The sheet to sheet variation in paper speed and contrast is greater than any variation due to compounding developers with a teaspoon. Get thee a densitometer and weep."

Is simply not true!

A master roll of paper from Ilford, Kodak and Fuji must be within a tighter tolerance than you imagine. And to realize that, the developer mixing must be accurate.

I think that the post of the blocks of wood was very much to the point Patrick.

PE