It isn't working strength developer that I keep in bottles it is the raw undiluted developer. Splitting a 5 litre container and not taking steps to prevent the remining developer to 'go off' is a no brainer. I have used the storage in 1/2 litre dark brown glass bottles for undiluted developer...
Not particularly “eco” with hydroquinone in it, I’d say. Usually “eco” is code for ascorbic acid or ascorbate based developers, usually with phenidone or dimezone, and usually lacking borates.
So, is Hydroquinone monosulfonic acid potassium salt a eco-friendly substitute for ”regular” Hydroquinone or is it just some kind of greenwashing going on?
I’m not an expert at this, @Alan Johnson would be able to give a more definitive answer. But from what I can tell: hydroquinone is not confirmed to be terrible for the environment, but it seems to have some impact in water sources. My guess is that the potassium salt is more stable until it’s in solution, less likely to react with other things but once in solution I expect you’re ending up with regular HQ.
HQMS (or the salt HQMS-K) is a relative of HQ but not a direct substitute. It has different characteristics in the context of photographic developers - for example it is a significantly less "active" developing agent than HQ with different oxidation product effects/interactions and superadditive properties.
I'm not sure if you are referring to the Moersch ECO developer above or some other eco developer but whether or not it is "eco-friendly" or maybe "eco-friendlier" than a developer containing HQ kind of depends on how you define that, the amount of the compound present etc.
So, is Hydroquinone monosulfonic acid potassium salt a eco-friendly substitute for ”regular” Hydroquinone or is it just some kind of greenwashing going on?
So, is Hydroquinone monosulfonic acid potassium salt a eco-friendly substitute for ”regular” Hydroquinone or is it just some kind of greenwashing going on?
Considering that a much larger amount of the potassium salt is needed, it is unlikely to be more eco-friendly. But it's certainly a significantly more expensive substitute.
I never had much to do with toxicology but from the above links I daresay post 9 is fair comment.
The potassium salt is also used in microfilm developers.