We recommend Zone Imaging Eco Zonefix.

This is to get best staining properties with your negatives. An acidic fixer can be used but is not ideal.

In short, it removes the stain given by staining developers like 510 Pyro which is not good.

For more detail, we will briefly outline what an acidic (buffered) stop bath is used for:

It is most known for its primary purpose – stopping development rapidly when the development times are relatively short – but it is used for other things too.

It is required for “preparing” the film for an acid hardening fixer only, lowering the amount of sludging and prolonging the life of such acidic fixers.

Acidic stop baths also remove developer oxidation by-products that occurred during development; but the pyro stain of 510 Pyro is the developer oxidation by-product and is thus desired.

Alkaline fixers are immune to sludging and are non-hardening thus the secondary requirements of acidic stop baths above are no longer applicable.

A water stop bath will allow minimal extra development in shadows for more shadow detail and enhance sharpness-adjacency effects from the now heavily diluted developer rapidly exhausting.

The advantages of alkaline over acid fixers are many:

They do not dissolve (bleach) the image’s silver from fixing for a long time, so the danger of over-fixing is minimised. This is particularly advantageous for tabular films when long fixing times are wanted to remove the residual dyes. Slower films with acidic fixers are extra susceptible to bleaching.

Alkaline fixers wash out significantly quicker saving a lot of water and time (this is still faster than an acid fixer used in combination with hypo clear). Depending on the fixer, an alkaline fixer can archivally wash in as little as 40 seconds.

Alkaline fixers are immune to sludge and thus can have more fixing capacity. They also have more tray and storage life in general.

Neutral fixers are odourless and have the above benefits but to a lesser extent for some.

Yes, it will work just fine.

That is the solvent darkening from age naturally but this doesn’t mean the developer is affected.

Your fixer will continue to work fine and the stain hasn’t affected the fixer’s functionality. You can still use the fixer for other developers that are non-staining.

All our B&W film developers are fully biodegradable. The main two developing agents of 510 Pyro are commercially sourced from plants only. Our fixer uses a plant sourced and biodegradable chelating agent.

As the solvent ingredient of 510 Pyro is becoming more and more bio-sourced, we aim to make 510 Pyro the world's first commercial B&W film developer to be more than 99.5% plant-based by 2050.

Our current developers on the market are highly concentrated so we can use small bottles compared to the typical litre bottles of traditional developers that have either the same or half film developing capacity.

This reduces plastic waste and more can be shipped at once. There is space and weight saving in the transit so less transport fuel is consumed. The bottles and caps are also recyclable.

Our current developers contain very little to no preservative thus the developer oxidises extremely fast after use. Heavily diluted 510 Pyro will completely oxidise in a few hours thus mitigating the environmental impact.

The main risks to the environment from film developers are the oxygen absorbing nature of the developing agents and the possibility of bio-accumulation of the components of the chemicals. If they are non or slowly biodegradable, a build up could suffocate aquatic life from less dissolved oxygen in the water and/or be subject to toxic concentrations.

Hydroquinone is a documented carcinogen, is very oxygen hungry and stays in the eco-system for several weeks. It oxidises into the hydroquinone monosulphonate ion which further oxidises thus taking up a lot of oxygen. It is the most popular developing agent where over 90% of film or paper developers formulated have contained this since the 1920’s.

DPTA/EDTA are non-biodegradable and are sourced from petroleum products. They are very powerful chelating agents and are needed for better stability of the developer solution. Chelating agents are mandatory for phenidone-ascorbate developers (the developer agent combination seen as most environmentally-friendly). Some chelating agents are biodegradable and aren’t sourced from petroleum products. Some developers can be formulated to not require chelating agents at all as they do impact image quality.

For all the information you need on how to use our products, please download their technical data sheets by clicking here

We have safety data sheets for our products in multiple languages, please find them by clicking here

No. Pyrogallol, and in turn 510 Pyro, is not classified as toxic by the UN’s Globally Harmonised System (GHS) and EU’s ECHA. Toxic classification requires acute toxicity category 1, 2 or 3 where 1 is the highest category; pure pyrogallol is on the lowest category at 4.

Pyrogallol, which is a major ingredient of 510 Pyro, is instead classified as harmful, a lower classification and further to this, it is diluted for the concentrate relative to pure pyrogallol. Commonly used developer agents like hydroquinone or phenidone are also classified as harmful as they are also category 4.

Unlike hydroquinone and phenidone, pyrogallol is a common naturally occurring chemical found in many plants, fruits and vegetables including radishes, agave, pomegranate, coffee and some teas.

Full information on pyrogallol classification, labelling and hazards can be found at the ECHA’s website here:

https://echa.europa.eu/substance-information/-/substanceinfo/100.001.603

A third party PhD chemist, Alex, has a fascinating video on safety, handling and disposal of 510 Pyro where he does go into pyrogallol in detail, please find the link here.

Please head to the Film Processing Lab page and scroll down to the bottom.