Dear Dr.Menche,
             Here at IIT Bombay we etch Cr film using saturated Potassium
Ferricynide (K3Fe (CN)6) solution in deionised water. This etchant does
not destroy either NPR or PPR resists that we use. (Waycoat SC-180, MERK
selectilux S, Shipley 1400-31).
             The etch rate of this solution is 400 A/min and can be
accelarated by putting trace amount of NaOH solution. (But this can only
be done if NPR is used as PPR reacts with alkalis.)

             You can also use the following recipe for precision
patterning of Cr deposited on SiO2 type substrates:-

164.5g Ce(SO4)2.2(NH4)2SO4.2H2O, 43ml HClO4, add water to make 1litre.
Operating temperature of 30 deg C.
        Etch rate is 150 A/min


Let me know if you need any more info. in this regard.

Regards
Amit