DIY Rodinal, are the crystals needed?

[Rafael Saffirio]

Hi, I did my second batch of homemade rodinal https://varezers.org/rodiynal/ in the first batch I keep the crystals on the bottle but I had to filter the diluted developer before using it because it has a lot of stuff floating, Can I just filter the whole batch after waiting 3 or 4 day and the bottle it? or the crystal are somehow needed?

 

[AgX]

In an equilibrium state a precipitate could be taken off, without effect on that equilibrium.

BUT this would apply only as long the environmental situation is not changed.

 

[Bronson Dugnutt]

Try warming the entire bottle in a water bath to re-dissolve the crystals before performing a mechanical filtration to remove other solids. Crystals of sodium salts will form in such a highly concentrated solution, potentially altering the pH of the remaining liquid and affecting developer activity, especially at high dilutions.

I have a batch of homemade rodinal formulated with potassium hydroxide that is about 3 years old with no signs of crystallization, owing to the potassium salt's higher solubility.

 

[revdoc]

When I make parodinal, I often get undissolved sodium sulfite crystals, especially if the temperature drops. There is enough sulfite in the developer without them, so they can be left or removed.

The original Rodinal uses metabisulfite rathe than sulfite, which is more soluble than sulfite. That is why you don't always see any crystals in the commercial product.

 

[Raghu Kuvempunagar]

I had to filter the diluted developer before using it because it has a lot of stuff floating,

If the crystals were Sodium sulphite, they should have dissolved readily in the diluted developer. I suspect that the floating stuff is probably not sulphite. Btw what colour do the crystals and floating stuff have?

 

[Rafael Saffirio]

The original Rodinal uses metabisulfite rathe than sulfite,

I had no idea about the metabisulfite, is the same amount as sodium sulfite?

Btw what colour do the crystals and floating stuff have?

Like this

 

[Raghu Kuvempunagar]

Oh you're using Paracetamol tablets! The floating stuff could be some filler material (i.e. inactive ingredients) in the tablets.

 

[Marcelo Paniagua]

Oh you're using Paracetamol tablets! The floating stuff could be some filler material (i.e. inactive ingredients) in the tablets.

So ok to filter. Normally use some cotton or Even coffee filter in a regular basis. I don't think there in any effect. Do high dilutions all the time and performance is consistent enough.