Here's the Ansco 120 formula:
Ansco 120
(soft-working developer)
Water (125 deg. F.) -------- 750.0 ml
Metol ----------------------- 12.3 g
Sodium Sulfite -------------- 36.0 g
Sod. Carbonate (mono.) ----36.0 g (31 g anhy.)
Potassium Bromide --------- 1.8 g
Water to make -------------- 1.0 liter
Low-contrast developer, suitable for print solarization. Standard dilution is 1:2. but can be used one part developer to four parts water, or full strength. Use dilution according to contrast required. (Also known as GAF 120.)
Compare that with D-165 ("Selectol Soft")/ID-3
Kodak D-165 = ID-3
Water 125° F (52 C) -------- 750 ml
Elon (Metol) -------------------- 6 g
Sodium Sulfite Anhydrous ---- 25 g
Sodium Carbonate Anhyd. --- 37 g
Potassium Bromide ------------1 g
Cool water to make 1 liter
Dilute 1:1 – 1:3 for use.
And finally,
Gevaert G-253
Soft working and gives clean blacks.
Warm water ----------------- 800 ml
Metol -------------------------- 3 g
Sodium Sulfite, anhyd. --------- 20 g
Sodium Carbonate, anhyd.---- 20 g
Potassium Bromide ------------1 g
Water to make -----------------1 liter
dilute 1:1 normal development time 2 minutes.
You'll see lots of similarities. The formulas are all similar in effect, with those with less Metol in the working solution giving the lowest contrast (e.g., D-165 1+3 has the same amount of Metol as G-253 1+1). I've use D-165/ID-3 often with good results at the 1+1 dilution.
Best,
Doremus