Help! Used wrong carbonate in Ansco 130

[Lyn Arnold]

I mixed up Ansco 130 (Evan Clarke's variant) and just realized I used Potassium Carbonate instead of Sodium Carbonate.

Do I chuck the lot and start again?

Thanks in advance,
Lyn Arnold

 

[john_s]

No, don't chuck it. These two are generally interchangeable. However, since they have different molecular weights, the amount of potassium carbonate has to be a bit more than the equivalent amount of sodium carbonate. If the sodium carbonate in the formula was anhydrous, use 1.304 times the amount. If the formula called for sodium carbonate monohydrate, use 1.115 times the amount.

If you are uncertain about the maths, post the formula here.

 

[Lyn Arnold]

Thank you, thank you.

I've been mixing this formula up for a few years, but took down the wrong jar. Must have been a 'seniors moment'. Fortunately, I always check as I'm returning the raw materials to the shelf.

Great to have APUG and all its very generous members so readily available.

Lyn

 

[PVia]

Lyn,

Please check back with this thread to tell us how it worked out for you, differences, etc...

I'd love to hear about it. Thanks!

 

[Lyn Arnold]

I do not have any of the old batch of Ansco 130 left. Comparing a new batch print with a previous batch print would not be very helpful for finer detail; the prints would need to be identical and exposed under the same conditions.

The developer seems OK. I have only used it so far for a few contact sheets. If I find substantial differences I will certainly post the results.

Lyn

 

[Christopher Walrath]

If needed, I have a volume interchange on my website. Can't access mobily. It's on the through the technical portal.

Http/::home.comcast.net/~flash19901

 

[mts]

Set the amount of carbonate as needed to achieve specified pH. Adjusting for molecular weight is a starting point to get it right, but owing to water of hydration and variations in the source, storage, etc. you cannot be certain by using either form according to weight alone.

 

[john_s]

Set the amount of carbonate as needed to achieve specified pH. Adjusting for molecular weight is a starting point to get it right, but owing to water of hydration and variations in the source, storage, etc. you cannot be certain by using either form according to weight alone.

This page contains information about the various levels of hydration of sodium carbonate: http://www.genchem.com/properties.asp

The monohydrate is commonly preferred since it's relatively stable.

Potassium carbonate, as far as I know, is normally sold as anhydrous but it has a strong tendency to absorb water from the atmosphere, so storage conditions are important. You could easily be using less than you thought if your pot carb had absorbed lots of water. (Could you detect this by a change in physical appearance? Many compounds go from free flowing powder to lumps when they absorb water)

So in both cases, accuracy could be elusive.

Fortunately photo formulas are not so critical.

The use of potassium instead of sodium is cited as giving warmer tones. Maybe this could be expected in this case.

 

[Lyn Arnold]

Thank you all. I hope to get into the darkroom today for some printing so will be keen to use the new batch of Ansco 130.

john_s: the potassium carbonate was quite dry, so am guessing it remained in anhydrous state.


Chris: thanks for the link.

Lyn

 

[Christopher Walrath]

You're welcome.

 

[Ian Grant]

Potassium Carbonate gives warmer tones than Sodium Carbonate and is usually used in commercial liquid concentrates due to it's higher solubility. The substitution is 9g Potassium Carbonate per 10g Sodium Carbonate (both Anhydrous) so in this formula it's not a big problem just a touch more alkali.

Both carbonates are more normally sold as Anhydrous in most parts of the world, except the US where monohyrated forms are common as well.

Ian

 

[john_s]

.... The substitution is 9g Potassium Carbonate per 10g Sodium Carbonate (both Anhydrous) so in this formula it's not a big problem just a touch more alkali.........Ian

MW of potassium carbonate (anhydrous) is 138.2
MW of sodium carbonate (anhydrous) is 106

So wouldn't one use 13g potassium carbonate for 10g of sodium carbonate?

 

[Ian Grant]

It is I just realised my mistake it's 9g Potassium Carbonate (anhyd) for 10g Sodium Carbonate (Monohydreated), or 13g Potassium Carbonate for 10 g Sodium Carbonate - both anhydrous.

I never work with Monohydrated as it's not as commonly available in the UK & Europe, in addition I usually substitute a mix of Potassium Carbonate and Sodium or Potassium Hydroxide for Sodium Carbonate in paper developers as I can make up more concentrated stock solution that way with less risk of crystallisation during storage. (So I never do a direct substitution)

Ian

 

[john_s]

.............I usually substitute a mix of Potassium Carbonate and Sodium or Potassium Hydroxide for Sodium Carbonate in paper developers as I can make up more concentrated stock solution that way with less risk of crystallisation during storage. (So I never do a direct substitution)

Ian

I use potassium carbonate instead of sodium carbonate when I make up ID-78 which is the only paper developer I use. With the substitution, I can make it up at 3x the normal strength. I put it in 500mL bottles which make up 3Litre of working solution: 2 Litre for the Nova plus 1 L for topping up.

I've never thought of incorporating hydroxide though. I think Agfa used hydroxide in some liquid paper developers, possibly because you get a lot of pH increase with very minimal cost.

Ian, do you do it to get colder images? Does the developer then have a shorter tray life?

 

[Ian Grant]

John, my experience is that the image colour isn't affected by adding hydroxide instead of some of the carbonate in ID-78 which is the main print developer I've used for many years, and there's no noticeable effect on tray or shelf life.

In practice all the major companies use some Hydroxide alongside Potassium Carbonate in their liquid concentrate developers, Agfa a bit more than Ilford & Kodak. I make up my ID-78 at 2.5X Ilford's published formula but on occasions the Potassium Carbonate crystallised out so I cut the level and added hydroxide which prevents this happening. I've tried both substitution ratios Ilford's and Agfa's in ID-78 and both work equally as well.

Ian

 

[dpurdy]

This question of Potassium vs Sodium carbonate comes up with Pyrocat a lot. I use pyrocat and Sodium Carbonate instead of the original formula for potassium Carbonate. All the research I have done tells me that for a working strength liter of developer I can use either 7.5 grams Potassium Carbonate or 10 grams Sodium Carbonate. Instead of the premixed part B with concentrated Carbonate, that is what I do. I add 10 grams of Sodium Carbonate per liter working solution and it works perfect for me.
Dennis

 

[Lyn Arnold]

Thank you all once again. I 'corrected' the 2 litre batch after the advice from john_s using his suggestion of 1.304 times the amount of anhydrous potassium carbonate for the stated sodium carbonate (160g). So I added an extra 48g of pot carb. This fits with the later recommendation of 13g pot carb for 10g of sod carb. ...I think??????????? I'm old and was never a hot shot at maths.

Anyhow, the developer seems to be OK, although a little colder than warmer, but have only been doing some rough prints on Kentmere VC select. Printing on some Foma fibre paper will show me any gross differences.

Thanks also for the post about potassium vs sodium carbonate in Pyrocat formulae. I use Pyrocat-HD and have now depleted my stock of pot carb, so will be able to use sod carb if necessary.

Lyn