Getting a scale for Metolian consistency

[Ulophot]

After a week of fairly concentrated testing to resolve some film development issues, track down one anomaly, and generally get my processing finally locked down -- an effort occasioned by adapting to my new LED head's different contrast from my previous coldlight, as posted in various threads -- I have finally decided to invest in a gem scale for my Metol measurement. The latest batch from the Formulary has even greater "stickiness" and "lofty" texture than the previous one bought several years ago, though I have silica in the jar with it, and levelling the spoon is chancier. I have been using careful spoon measurements for my D23 for several years, but since it seemed that I might be getting less Metol per measurement now than before, I went downstairs and measured some out on the kitchen digital scale. Instead of (the hoped for) 7-8 grams per 2 Tsp, the scale said 5 . Is the scale accurate in this range? No idea; probably not. Have I been using 5 gms all this time? Again, a question mark. In any case, Metol being a bit like flour-- very compressible -- in baking bread (which I do weigh, since I bake infrequently), the scale will let me sleep better.

I am so tired of testing just to get N-5 to N+3 settled, that the thought of inserting a new variable almost made me reject the idea. But whatever the new scale shows, I can easily adjust my times by percentage once I adjust for N.

I am determined to make 2023 one of making images, not testing! Zum werk -- to the work!

[RandyB]

I can see your problem. I have often thought of getting a small digital scale for measuring less than 1 gram but ran into the problem of how do I calibrate the scale for 1/2 gram. Since I have a rare need for measuring that small of an amount I just passed on the thought. For now I'll continue to use the balance scale that I've used for the past 40 years. It is accurate down to 1 gram when used with the calibrated weight set.

You might look into getting a weight set so that you can check the accuracy of your kitchen scale. You can find small digital scales at Harbor Freight at a reasonable price, but you do need something "calibrated" to check their accuracy.

[malexand]

You can get decent digital milligram scales from major online retail site for less than $50
Mine came with a calibration weight too.

[Tin Can]

I have 4 digital scales all are needed

I buy cheap from AMAZON or eBay

They all work perfectly

The smallest responds to breathing

I used this type at my first lab job https://www.hogentogler.com/mettler-toledo/mettler-toledo-xpr56dr-micro-analytical-balance.asp?gclid=CjwKCAiAwc-dBhA7EiwAxPRylOOS3m5hmc0OajqvEuP02zLMB8zyFCsJ8zMSXq6GmYWUxN1IVSOguBoCM2cQAvD_BwE

I now use this, don't breathe https://www.amazon.com/Fuzion-Portable-Back-Lit-Stainless-Included/dp/B07SL2TBBD/ref=sr_1_3_sspa?crid=IAA02OOA76AI&keywords=milligram+scale&qid=1672751560&sprefix=milligram+scale%2Caps%2C116&sr=8-3-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEyRk9GWk9QUFNFOUM1JmVuY3J5cHRlZElkPUEwNjg3NDEyMU0wMFpSS0xBVVZYNiZlbmNyeXB0ZWRBZElkPUEwMDgxOTYxMjZPUDVMVzZFRDVRRSZ3aWRnZXROYW1lPXNwX2F0ZiZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=



I uses

[Doremus Scudder]

Hi Philip

Yes, you should invest in a scale, digital or otherwise, that is accurate down to small increments of a gram just to "calibrate" your spoon recipes, if nothing else. Bite the bullet and get something. I got a wonderful Ohaus triple-beam balance scale for next to nothing from a police auction (no longer needed evidence seized in a drug bust). I've seen deals on eBay, etc. too.

Once you have a decent scale, you can figure out the spoon weight of your current batch of Metol (and whatever else). If you can be consistent with your spooning, and the consistency of the chemical is uniform, then you can simply figure out the right spoon weight for each different batch. That's what I do. Also, you'll then have a scale for formulae that require more precision.

Of course, if your dry chemical does not have a uniform consistency, then weighing it out each time is really the best method.

Best,

Doremus

[domaz]

I got a wonderful Ohaus triple-beam balance scale for next to nothing from a police auction (no longer needed evidence seized in a drug bust). I've seen deals on eBay, etc. too.


I got a Ohaus digital scale on Ebay, worked great for a while then stopped working. Turns out it was clogged with weed that had somehow worked it's way in. So buyer beware having weed in a used scale is humorous, having something else in one (Fentanyl) could be bad...

[Ulophot]

(See additional post below)

Scale arrived, and I immediately took it to the darkroom and calibrated it. Then, knowing my gently levelled teaspoons were giving me less than needed (I corrected my earlier post on this, in which I carelessly misstated my experience), I dumped on heaping spoons. Lo and behold, it took three to reach 7.5 g. I thought I'd see what it would come out to it I packed the Metol into spoon and then levelled. It came to about 2 tsp plus 2/3.

So, now I need to guess how to adjust my development time for my first test. Here's my thinking, and I'll appreciate any corrections on this, because mathematics is, shall I say euphemistically, not my forté.

Using D23 stock instead of my usual 1:1, I find that multiplying the time by 0.7 gives the equivalent development. If I increase my stock concentration by the approximately 1/3 indicated above (each of the two teaspoons of Metol per liter of stock is becoming about 1 and 1/3), my time for either stock or 1:1 should decrease by something like 20%.

Does that make sense or am I way off?

Thanks.

[Paul Ron]

i guess digital is the way to go these days.. cheap, small, light and pretty accurate. my old triple beam lab scale uses way to much counter space but its accurate balls on.

[Ulophot]

As usual, I can't measure, or think when measuring. My post above, i just realized, is off, big-time: I was comparing compressed spoonfuls with uncompressed. Duh...

In fact, my uncompressed tsp comes in at around 1.8+ gram, meaning I have been using 3.6-3.7 instead of 7.5 per liter. I'm inclined, therefore, to cut my present N development for 1:1 from 10.5 min to 7 for a first try.

How does that sound?

[Paul Ron]

youre measuring chemicals as if you are baking a cake?... hahahaha
get a scale!

https://www.amazon.com/triple-beam-scale/s?k=triple+beam+scale

also see tc scale?... $7!

[Alan Klein]

You can always sell it to the cartel when you no longer need it.

[Ulophot]

youre measuring chemicals as if you are baking a cake?... hahahaha
get a scale!

https://www.amazon.com/triple-beam-scale/s?k=triple+beam+scale

also see tc scale?... $7!

I got the SmartWeigh Gem 20. Smaller than expected; included "cup" is too small for my Metol. Folded wax paper does the trick, but it's good that my amount is small.

[Doremus Scudder]

Philip,

Now that you have a reliable scale, and assuming your Metol is of uniform consistency, weigh out a level teaspoon a few times and take the average. Use that for your spoon recipes. Do that with your sodium sulfite and you should be able to figure an accurate spoon recipe for D-23. Then it's just like baking a cake!

Doremus

[Ulophot]

Doremus, good in theory, but as noted, the Metol consistency is a question mark for me, since the stuff is so very compressible and, in this batch, sticks together so well that it slips around in the spoon when levelling. I'm happier with weighing. My sulfite, borax, and carbonate crystals are no problem for spoons, and I can use the scale on the rare occasions I need small amounts, e.g., for SLIMT stocks.

Any wisdom to offer on my timing issue (yesterday's posts in this thread)?

[Michael R]

I’m confused so hopefully Doremus answers :D

Based on post #7 I was thinking you were used to using two compacted spoonfuls before checking the scale so I thought the scale was telling us you had effectively been using approx 5.5g/l metol to make your stock D-23. But now you’re saying you were using 3.6-3.7g (non-compacted spoonfuls).

[Drew Wiley]

I'm confused about the difference between Metolians and Martians, or perhaps Metropolitans, as well as the substitution of metol for baking soda when making a cake. But otherwise, I've always been a little leery of interchanging spoonfuls of anything in the lab for actual prescribed gram weights. Decent gram scales are cheap enough. And a hundred little poly weighing dishes don't cost much, and will last a long time, since you can simply rinse them out afterwards. Metol is fairly aggressive, and relatively small errors in quantity can have an outsized impact on the overall formula consistency.

[Paul Ron]

Plus chemistry is all abouit weights not teaspoons. Sometimes that extra variable gram is the problem with your results.

[Ulophot]

I’m confused so hopefully Doremus answers :D

Based on post #7 I was thinking you were used to using two compacted spoonfuls before checking the scale so I thought the scale was telling us you had effectively been using approx 5.5g/l metol to make your stock D-23. But now you’re saying you were using 3.6-3.7g (non-compacted spoonfuls).

I am more confused than you, Michael, but my wife could have told you that decades ago. On the matter at hand:

I had been used to using fairly uncompressed spoonfuls, levelled, but, with the scale having arrived, I found that each was only something like 1.8 g, at least with this new batch, with its noted characteristics. I mixed up a fresh liter using the scale to measure 7.5 g and used my usual 4 Tbs of sulfite, which measures easily.

I developed one for 7 minutes and found it to be way too thin, much to my surprise and chagrin. I am just waiting for another neg, developed for 9 1/2 minutes, to dry. If it's close, I'll be more confused than ever, since my old time was 9 minutes -- except that that was for using my coldlight head, which was adding more contrast than I realized. From the initial appearance of this latest neg, I expect 9 or 9 1/2 minutes to be on target, and then will simply apply the percentage change to my other times and only adjust further if a particular time is off. I'm close to being done with this painfully extended exercise. Hallelujah!

[Michael R]

There have certainly been some twists and turns so hopefully not too much testing left.

Ending up with a longer development time with roughly twice the metol concentration would be a little strange, though I wouldn’t be all that surprised if the times were closer than one might expect. I say this because we need to keep pH in mind. The normal pH of fresh D-23 is 8. This is the net result of the alkaline sodium sulfite and acidic metol salt. Since we think you might have been using significantly less than 7.5g metol, it is possible the pH of your version of D-23 (let’s call it D-23U ;)) was a little higher. I’d have to measure it to know for sure. A higher pH would boost the activity of the weaker solution, lessening the expected difference in development times due to the difference in metol concentration alone. I wouldn’t expect this small pH increase to completely offset the lower metol concentration though, so perhaps there is also something being contributed by the change in enlarger light source. That would be expected since the two types of lighting put out different wavelengths.


I am more confused than you, Michael, but my wife could have told you that decades ago. On the matter at hand:

I had been used to using fairly uncompressed spoonfuls, levelled, but, with the scale having arrived, I found that each was only something like 1.8 g, at least with this new batch, with its noted characteristics. I mixed up a fresh liter using the scale to measure 7.5 g and used my usual 4 Tbs of sulfite, which measures easily.

I developed one for 7 minutes and found it to be way too thin, much to my surprise and chagrin. I am just waiting for another neg, developed for 9 1/2 minutes, to dry. If it's close, I'll be more confused than ever, since my old time was 9 minutes -- except that that was for using my coldlight head, which was adding more contrast than I realized. From the initial appearance of this latest neg, I expect 9 or 9 1/2 minutes to be on target, and then will simply apply the percentage change to my other times and only adjust further if a particular time is off. I'm close to being done with this painfully extended exercise. Hallelujah!

[LabRat]

To hold chems while measuring, I use standard Dixie paper drink cups... They are remarkably even in tare weight (within less than 1/10gm one to another), easy to shake chems in/out, large enough to hold enough chem for more than a liter to mix, and cheap enough to use a fresh one for each chem...

Easy way to measure, then shaken into the solution with the magnetic mixer...

Steve K

[Tin Can]

Good idea!

Must be the plain paper, not wax cups

I was looking on Amazon yesterday for new Tare cups

No findum

will look again

I have a few left

I need much smaller cups


To hold chems while measuring, I use standard Dixie paper drink cups... They are remarkably even in tare weight (within less than 1/10gm one to another), easy to shake chems in/out, large enough to hold enough chem for more than a liter to mix, and cheap enough to use a fresh one for each chem...

Easy way to measure, then shaken into the solution with the magnetic mixer...

Steve K

[Tin Can]

Found um

Last ordered 2015!

https://www.amazon.com/SEOH-Plastic-Hexagonal-Weigh-Boats/dp/B001AEBLMQ/ref=sr_1_9?gclid=Cj0KCQiAzeSdBhC4ARIsACj36uHarn_fqzz76af-o4vmOXd4PA3sGXOGB3LOWa43GVF2bLitCzkKR_IaApl2EALw_wcB&hvadid=616863311928&hvdev=c&hvlocphy=9022737&hvnetw=g&hvqmt=e&hvrand=4156757675671201164&hvtargid=kwd-1058450734&hydadcr=24664_13611849&keywords=weigh+boats&qid=1673101948&sr=8-9

[Michael R]

You can also use cupcake/muffin papers liners. Hundreds for dirt cheap and they take up no space. I use them for things like carbonate, sulfite… I just get them at the supermarket. They each weigh 0.5g. For small amounts and/or trickier compounds I just use little weighing papers I cut from plain paper.


Found um

Last ordered 2015!

https://www.amazon.com/SEOH-Plastic-Hexagonal-Weigh-Boats/dp/B001AEBLMQ/ref=sr_1_9?gclid=Cj0KCQiAzeSdBhC4ARIsACj36uHarn_fqzz76af-o4vmOXd4PA3sGXOGB3LOWa43GVF2bLitCzkKR_IaApl2EALw_wcB&hvadid=616863311928&hvdev=c&hvlocphy=9022737&hvnetw=g&hvqmt=e&hvrand=4156757675671201164&hvtargid=kwd-1058450734&hydadcr=24664_13611849&keywords=weigh+boats&qid=1673101948&sr=8-9

[Doremus Scudder]

Philip,

If your Metol isn't of even enough consistency or compresses irregularly, then weighing instead of using spoon measures will certainly be more accurate and precise.

I only advocate spoon recipes for situations where the volume measurement can be easily and accurately repeated. It helps also when the formula is one that has a larger margin of error. My Metol is of even enough consistency that I'm not concerned about using spoon measurements to mix print developers. I'd likely want to be sure that my spooning was repeatable before using it for D-23 or other film developers, which is why I suggested weighing out a few teaspoons to see if you could find a mean volume that gave you the weight you needed within a reasonable variation for the developer you're compounding. If you can't, the get out the scales.

For those that disparage spoon recipes, however, I'd just like to point out that volume measurements of things with an even consistency can be extremely accurate (that's what we do with liquids, right?). And, weighing things out isn't always as precise as we think. Powdered chemicals often absorb water from the air, changing the amount of active ingredient per unit of weight. Weighing out an amount of older sodium carbonate anhydrous can get you significantly less carbonate that you think you're getting if there has been significant water absorption.

It's important to know how precise you need to be with a specific formula and weigh that against the convenience of using the likely less-accurate spoon measures. If slight variations in proportions make a significant difference, then use the most precise methods of measuring possible. If not, save a bit of time and grab the measuring spoons.

Best,

Doremus

[Tin Can]

I don't care what method anybody uses

I worked in test labs most of my life

I treat every chem/food/etc as poison

I am careful

I quit a Chem lab age 21 because one damn fool thought fluffy asbestos was 'pretty'

He would toss a handful into light

An oven also exploded as the 'scientist' wrote a procedure and he not think about glue solvent vapor

I was looking at the locked oven and somehow felt the pressure minutes before the door blew with a big boom

So big it shut down the whole huge factory

I don't trust experts

guns either

'experts' told me several times, it was not loaded

[Michael R]

Agree. Particularly in the case of D-23 the amounts are large enough that quite of bit of measurement slop can be tolerated. Even in Haist’s book for example (which like any proper chem book has an entire chapter devoted to mixing, calculations etc.) the “spoon” version of D-23 makes an appearance as legit.

Print developers too, in general.


Philip,

If your Metol isn't of even enough consistency or compresses irregularly, then weighing instead of using spoon measures will certainly be more accurate and precise.

I only advocate spoon recipes for situations where the volume measurement can be easily and accurately repeated. It helps also when the formula is one that has a larger margin of error. My Metol is of even enough consistency that I'm not concerned about using spoon measurements to mix print developers. I'd likely want to be sure that my spooning was repeatable before using it for D-23 or other film developers, which is why I suggested weighing out a few teaspoons to see if you could find a mean volume that gave you the weight you needed within a reasonable variation for the developer you're compounding. If you can't, the get out the scales.

For those that disparage spoon recipes, however, I'd just like to point out that volume measurements of things with an even consistency can be extremely accurate (that's what we do with liquids, right?). And, weighing things out isn't always as precise as we think. Powdered chemicals often absorb water from the air, changing the amount of active ingredient per unit of weight. Weighing out an amount of older sodium carbonate anhydrous can get you significantly less carbonate that you think you're getting if there has been significant water absorption.

It's important to know how precise you need to be with a specific formula and weigh that against the convenience of using the likely less-accurate spoon measures. If slight variations in proportions make a significant difference, then use the most precise methods of measuring possible. If not, save a bit of time and grab the measuring spoons.

Best,

Doremus

[Tin Can]

I have long just spooned Citric Acid Powder for stop

almost ready to begin D23

I will store my Rodinol for harder times

I have plenty of D23 part a and part b

I follow Ken Lee as he has always made sense

D 23

https://www.kennethleegallery.com/html/tech/D-23.php#:~:text=D%2D23%20is%20a%20general,handle%20scenes%20of%20high%20contrast.

[Michael R]

D-23 is great, and simple/fast to mix. It was originally formulated to work similarly to D-76, which is still about as good as it gets. Rodinal is of course good too, so you’re in good shape.

Ken is a good guy.


I have long just spooned Citric Acid Powder for stop

almost ready to begin D23

I will store my Rodinol for harder times

I have plenty of D23 part a and part b

I follow Ken Lee as he has always made sense

D 23

https://www.kennethleegallery.com/html/tech/D-23.php#:~:text=D%2D23%20is%20a%20general,handle%20scenes%20of%20high%20contrast.