Barry Thornton's two-bath question about time and temperature

[John Wiegerink]

About 7 years ago I bought a generic digital scales (American Weigh Scales brand, Digital Pocket Weight Scales, made in China of course lol) on Amazon for $18. It has served me well in the years I have owned it, without any issues whatsoever. I think that the trick (if you can call it that) with these pocket sized digital scales is: NEVER drop them, or you'll eff them up. I've been very careful not to bang or drop mine, so it still works perfectly 7 years later.

It's easy to look at an $18 device and think "that's gotta be junk" and often, you'd be right. But I have relied on this to measure my chemistry and it has been reliable and (apparently) accurate. I measure amounts as small as 0.25 grams of Phenidone and have no difficulty trusting the measurements. I suggest this is a reasonable scales to choose for your purpose.

+1. I hate buying stuff from China, but would hate to know what one of these scales would cost if it said, "Made in the USA". I have several of these Chinese ones for general purpose[pose weights and one that is so sensitive you have to use a plastic dome over the scale or your exhaled breath will trigger it. Works excellent for measuring phenidone in very small quantities.

 

[PicklesFrog]

My last two chemicals arrived today from Photographer's Formulary. Just one question regarding the sodium metaborate, it arrived a bit chunky when I opened it. Is this normal for this chemical? The metol and sodium sulphite anhydrous seemed normal. I have reviewed the SDS sheets for each.

Also, any mixing or preparation tips I should know?

sodium metaborate (and any other sodiums you may have) takes water from the air. thats probably what happened. just use a mortar and pestle to grind it up and pour it back into the bottle. this can happen at any point, even if its "sealed" as once its exposed to air it takes water slowly but surely.
nothing to worry about, again just grind it out.

as per snusmumriken said, the pinch of sulfite (i just grab 1/4th of a spoonful) before adding the metol and dissolving.

 

[PicklesFrog]

You don’t need to buy metaborate as such. See this thread.

still no scans or darkroom (rip)
but i did the hydroxide-borax reaction and the negatives turned out pretty well! used hp5 and kentmere 400 and both densities and rebates came out good to my eye. maybe a little under developed but my room is cold currently.
thanks for the advice going to use this from now on. i did make up a carbonate solution to test out but honestly i think this will work for the most part.

 

[Chuck_P]

sodium metaborate (and any other sodiums you may have) takes water from the air. thats probably what happened. just use a mortar and pestle to grind it up and pour it back into the bottle. this can happen at any point, even if its "sealed" as once its exposed to air it takes water slowly but surely.
nothing to worry about, again just grind it out.

as per snusmumriken said, the pinch of sulfite (i just grab 1/4th of a spoonful) before adding the metol and dissolving.

I just so happen to have a mortar and pestle and I'll do that, thank you.

 

[Chuck_P]

...........and the usual thing about putting in a pinch of the sulphite before dissolving the metol, to minimise oxidation. Add the rest of the sulphite when the metol is completely dissolved. And don’t use the developer the same day.

Thanks for that tip, but why can't the developer be used the same day?

 

[snusmumriken]

Thanks for that tip, but why can't the developer be used the same day?

I’ve found that what looks to be completely dissolved ain’t necessarily so. Of course you could filter before use, but waiting till tomorrow is a lot easier, unless you enjoy retouching prints.

I’ve also read that this developer can be a bit ‘hot’ when first mixed. I’m not convinced that does apply to BT2B, although it can apply to other developers. It was certainly the case with Emofin, for example. That effect must surely be something to do with the by-products of development having a retarding effect in later use, and not to do with the time elapsed per se? But I’m no chemist, I can only report my experience, and I’ve not noticed this effect with BT2B.

 

[Chuck_P]

I’ve found that what looks to be completely dissolved ain’t necessarily so. Of course you could filter before use, but waiting till tomorrow is a lot easier, unless you enjoy retouching prints.

Noted, thanks. I'm about to mix my first bath A and bath B, so should be good to go in a couple of days after it warms a bit at my location. I want to expose a step tablet contacted to 4x5 film, but it's very cold for my location right now and I don't do well futzing with a LF camera in biting cold air. Perhaps by the weekend.

 

[Milpool]

I’ve found that what looks to be completely dissolved ain’t necessarily so. Of course you could filter before use, but waiting till tomorrow is a lot easier, unless you enjoy retouching prints.

I’ve also read that this developer can be a bit ‘hot’ when first mixed. I’m not convinced that does apply to BT2B, although it can apply to other developers. It was certainly the case with Emofin, for example. That effect must surely be something to do with the by-products of development having a retarding effect in later use, and not to do with the time elapsed per se? But I’m no chemist, I can only report my experience, and I’ve not noticed this effect with BT2B.

You can use a metol-sulfite developer (or the vast majority of developers) right away.

Best mixing practices include filtering the stock solutions after mixing particularly when it comes to scratch-mixing bulk technical grade compounds which will tend to have more junk in them than high purity stuff.

 

[Chuck_P]

You can use a metol-sulfite developer (or the vast majority of developers) right away.

Best mixing practices include filtering the stock solutions after mixing particularly when it comes to scratch-mixing bulk technical grade compounds which will tend to have more junk in them than high purity stuff.

My funnel has one of those little screens with a very tiny mesh shoved into the down spout, would that suffice?

 

[Milpool]

My funnel has one of those little screens with a very tiny mesh shoved into the down spout, would that suffice?

Hard to say for sure but if it’s a fine mesh it might be good enough. You can tell visually based on whether or not you see a significant amount of stuff floating around after mixing.

I don’t want to make too much out of this, just noting it in general. If you find the screen isn’t doing it, you can use any number of inexpensive things from coffee filters to cheese cloth (that was actually Grant Haist’s suggestion).

 

[Chuck_P]

I don’t want to make too much out of this, just noting it in general.

I take it all in stride.........any helpful tips are appreciated as I'm just starting out with doing some of my own mixing of chemicals.

 

[Chuck_P]

.........the pinch of sulfite (i just grab 1/4th of a spoonful) before adding the metol and dissolving.

Just a clarification, I should totally disolove the .25 tsp of sulfite before adding the metol or can both be added at same time to dissolve together? Thanks.

 

[retina_restoration]

Just a clarification, I should totally disolove the .25 tsp of sulfite before adding the metol or can both be added at same time to dissolve together? Thanks.

Always dissolve "a pinch" of the sulfite before adding any of the developing agents, yes. A pinch can literally be a pinch, or up to 1/4 tsp if you wish.
Adding the pinch of sulfite first scavenges oxygen from the water, and prevents premature oxidation of the Metol (or Hydroquinone).

 

[Chuck_P]

Always dissolve "a pinch" of the sulfite before adding any of the developing agents, yes. A pinch can literally be a pinch, or up to 1/4 tsp if you wish.
Adding the pinch of sulfite first scavenges oxygen from the water, and prevents premature oxidation of the Metol (or Hydroquinone).

thanks

 

[snusmumriken]

You can use a metol-sulfite developer (or the vast majority of developers) right away.

Best mixing practices include filtering the stock solutions after mixing particularly when it comes to scratch-mixing bulk technical grade compounds which will tend to have more junk in them than high purity stuff.

I can only describe what I find. If I filter bath A straight after mixing (the solution appearing clear), my Paterson filter funnel catches stuff. If I leave it to the next day, it doesn’t. It’s certainly only a very small fraction of the constituents, but I can’t see the point of filtering out stuff that will dissolve fully, given patience and a night’s sleep. My POV is coloured by a long-term battle against Things That Cause Spots On My Negatives (which I am winning!).

 

[Chuck_P]

The mixing seemed to go well. The metol seemed to want to cling to the stainless steel 1/4 tsp I was using, like little magnetized particles and there was a fair amount stuck to the little plastic tray that came with the scale, I guess it's a static cling. I did my best to scrape it out to get as much of the measured amount. I look forward to producing a couple of curves and I'll share the results.

 

[retina_restoration]

The mixing seemed to go well. The metol seemed to want to cling to the stainless steel 1/4 tsp I was using, like little magnetized particles and there was a fair amount stuck to the little plastic tray that came with the scale, I guess it's a static cling. I did my best to scrape it out to get as much of the measured amount. I look forward to producing a couple of curves and I'll share the results.

I use plastic condiment cups for measuring chemistry (wash and reuse). After dumping each chemical into the water, I pour some of the solution back into the cup to rinse out the last clinging particles. Seems to me the easiest thing to do to make sure you get it all.

 

[John Wiegerink]

I use plastic condiment cups for measuring chemistry (wash and reuse). After dumping each chemical into the water, I pour some of the solution back into the cup to rinse out the last clinging particles. Seems to me the easiest thing to do to make sure you get it all.

That's one way. I use the small bathroom dixie cup and throw them away after use. For big large quantities like sodium sulfite I'll use larger paper cups. Then I throw them away after use so as not to cross contaminate anything or worse yet drink out of one.

 

[retina_restoration]

That's one way. I use the small bathroom dixie cup and throw them away after use. For big large quantities like sodium sulfite I'll use larger paper cups. Then I throw them away after use so as not to cross contaminate anything or worse yet drink out of one.

As I am diligent about cleaning everything as soon as I'm done with it (and washing the spoon between chemicals), contamination isn't going to happen in my workspace. But this is certainly something every practitioner should be aware of, and adopt protocols to avoid it.

 

[Chuck_P]

I use plastic condiment cups for measuring chemistry (wash and reuse). After dumping each chemical into the water, I pour some of the solution back into the cup to rinse out the last clinging particles. Seems to me the easiest thing to do to make sure you get it all.

I have to admit that the trays that came with the scale were awkward when pouring the chemical into water, so I will probably need to do something similar.

 

[PicklesFrog]

The mixing seemed to go well. The metol seemed to want to cling to the stainless steel 1/4 tsp I was using, like little magnetized particles and there was a fair amount stuck to the little plastic tray that came with the scale, I guess it's a static cling. I did my best to scrape it out to get as much of the measured amount. I look forward to producing a couple of curves and I'll share the results.

i use coffee filters as a scale-to-water vehicle. it doubles as that and a filter to filter out the mixed liquid into the bottles.

 

[grahamp]

Squares of slick surface paper work well for weighing small amounts. Cut the edges with scissors, don't tear them, because torn edges can retain powder. You can buy laboratory weighing paper, but any slick coated paper is fine. At last, a use for all those unsolicited mail order catalogs!

It usually pays to lightly fold the paper before weighing to make it easier to pick up and pour the powder.

A cup or dish is better for larger weights.

 

[What About Bob]

You can use a metol-sulfite developer (or the vast majority of developers) right away.

Best mixing practices include filtering the stock solutions after mixing particularly when it comes to scratch-mixing bulk technical grade compounds which will tend to have more junk in them than high purity stuff.

Would this junk be the same thing as tiny black specks that occur in solution after developing? I posted a question last year about this when I was dumping the D-23 back into its graduate and saw black spots floating about. At first I thought the specks may have been from the film flaking off. First time ever noticing these black specks is when I started mixing my own developer and then when I bought from a different source the specks were much lesser to nonexistent.

 

[retina_restoration]

Would this junk be the same thing as tiny black specks that occur in solution after developing? I posted a question last year about this when I was dumping the D-23 back into its graduate and saw black spots floating about. At first I thought the specks may have been from the film flaking off. First time ever noticing these black specks is when I started mixing my own developer and then when I bought from a different source the specks were much lesser to nonexistent.

Probably.

 

[Chuck_P]

Would this junk be the same thing as tiny black specks that occur in solution after developing? I posted a question last year about this when I was dumping the D-23 back into its graduate and saw black spots floating about. At first I thought the specks may have been from the film flaking off. First time ever noticing these black specks is when I started mixing my own developer and then when I bought from a different source the specks were much lesser to nonexistent.

Interesting that you mention this. I can't remember which chemical it was but after weighing one of them, I noticed a black speck or two in the pile that was on the scale and I'm 100% certain that I scooped it up from within the container. I picked them out before mixing, perhaps something to keep an eye out for the next time you mix a batch.