Silberra Microl Developer, 250 ml, concentrate

Silberra Microl developer is a single-solution (one-shot) concentrated b&w negative film developer based on N-(4-Hydroxyphenyl) glycine (industrial manufacturing of that chemical is discontinued); due to that fact Silberra Microl developer shall be referred as limited edition product.

Silberra Microl is a professional black and white negative film developer which provides extra fine grain, perfect contour sharpness and wide and soft tonal range. Microl is engineered to process low sensitive films with high resolution, but works fine with any type of film.

Chemical Composition

N-(4-Hydroxyphenyl) glycine, sodium sulfite, potassium carbonate, 1-Phenyl-3-pyrazolidone, EDTA.

Preparing Stock Developer (mixing instructions)

Working solution is prepared by diluting the concentrate in distilled water while actively stirring. Since the working solution of Silberra Microl is not reusable, it is convenient to prepare it immediately before processing the film and to the volume that you need.
Dilute the concentrate of Silberra Microl to a ratio of 1+24 (i.e. 40 ml of concentrate to 960 ml of distilled (or filtered) water to obtain 1 liter of working solution. Don't aerate the solution: stirring speed shall be slow enough to not form air bubbles. We highly recommend using glass sticks or special plastic stirring sticks to avoid any unexpected chemical reactions. Never use steel or wooden sticks for stirring.
In order to get 300 ml of working solution you need to use 288 ml of distilled water and 12 ml of Silberra Microl concentrate.
In order to get 500 ml of working solution you need to use 480 ml of distilled water ans 20 ml of Silberra Microl concentrate.
The easiest way to achieve correct dilution is to use disposable syringe with ml scale, or small volume measuring glass.
Silberra Microl stock developer solution has life time about 12 hours; prepare as much stock solution as you are going to use in the next 12 hours (pay attention to the volume of the processing tank you're going to use and to the number of films).

Development Times

Silberra Microl stock developer has average development time of 11-14 minutes, depending on EI and temperature. The following development times for stock dilution are officialy tested for now:

Silberra PAN200 - ISO200 - 20C - 22 minutes
FujiFilm Neopan Acros 100 - 100ISO - 20C - 13 minutes
Ilford FP-4 Plus - 125ISO - 20C - 11 minutes
AGFAPhoto APX100 - 100ISO - 20C - 18 minutes
Fomapan 100 - 100ISO - 20C - 11 minutes

Usage Limits

Silberra Microl stock developer is one-shot non-reusable developer. To process 1 b&w film you should dilute at least 12 ml of the concentrate to stock ratio. Silberra Microl working solution’s effective usage limit for film is 3x135 type films per 1 litre (or 2x120 type films per 1 litre).

Storage

Keep Silberra Microl developer in a cool, dry and dark place. Keep away from children. All the solutions should be stored in tightly sealed bottles, with low internal air volume.

Expiry Date / Shelf Life

Concentrated Silberra Microl Developer may be stored in its original sealed bottle for up to 6 months. Working solution (i.e. stock developer) storage life is 3 days maximum. Partially used stock developer doesn't have any guaranteed shelf life.

Disposal Regulations

Silberra developers and fixers must be disposed of in accordance with the rules and regulations of the country they are used in. Concentrated developers could be toxic and may harm the environment unless disposed in appropriate manner. Silberra recommends to use special disposal services provided by correspondingly licensed organizations which are eligible for photographic chemistry recycling/disposal.