during and after W.W.II. photographers in the Czech Republic suffered from lack of fresh films - in fact one wasn't able to buy anything else than outdated film or paper. famous photography-oriented Czech inventor and chemist Ing. Premysl Koblic (aside from his famous Pextral developing method) formulated a special developer intended to use with outdated films.
so it's time to tell the whole world about it .)
Metol - 4 g
Sodium sulfite (anhydrous) - 16 g
Disodium phosphate (.12H2O) - 4 g
Borax (sodium tetraborate) - 8 g
water to make - 1000 ml (pH should be 8.5)
developing time suggested for the first film is around 8-15 min at 18 °C.
should be stored up to 6 months (and maybe more).
used developer can't be stored.
amount of Disodium phosphate can be altered up to 70 g/l - it acts as a restrainer of a fog&haze and other negative effects of long-time stored film.
film's speed will be slightly better than D-76 and negatives will be very sharp, fine grained, gelatine layer is very clear. prints should look crisp and sharp without annoying edge-effects caused by many actuance developers.
Delta 400 negatives have as good tonality as souped in DD-X but are super-sharp (can be seen even on 5x enargements as a huge difference).
btw - it can be diluted 1+1 with approximately doubling the development times, giving more compensation. using at higher temperatures than 20 °C cannot be recommended because of metol's soft-working nature.
btw2 - concentrated (3x ?) solution to be diluted before use can be made easily.
some sample shots from delta400 @ mpb 1+0 are attached. scanned enlargements from ilford mg iv rc and adox easy print in dektol made with condenser enlarger.