Table 8: Literature values for metallicity, and methods used. The two values given for NGC 2506 by Marconi et al. correspond to the best reproductions of the observed CMDs with synthetic ones based on the Padova tracks (Bressan et al. 1993) at Z=0.008 and 0.02; note that further unpublished analyses with updated evolutionary tracks have shown that the solar solution should be excluded. The two solutions for IC 4651 given by Anthony-Twarog & Twarog correspond to two different calibrations of the intrinsic b-y colour versus metallicity.

Reference		E(B-V)	method
NGC 2506
This paper	-0.20	0.073	high-res sp.
Geisler et al. (1992)	-0.58		Washington ph.
Friel & Janes (1993)	-0.52	0.05	low-res sp.
Marconi et al. (1997)	-0.4 to 0.0	0.05 to 0	synthetic CMD
Twarog et al. (1997)	-0.38	0.05	low-res sp.+ DDO
Friel et al. (2002)	-0.44	0.05	low-res sp.
NGC 6134
This paper	+0.15	0.363	high-res sp.
Clariá & Mermilliod (1992)	-0.05	0.35	Wash. + DDO
Twarog et al. (1997)	+0.18	0.35-0.39	DDO
Bruntt et al. (1999)	+0.28	0.365	Strömgren
IC 4651
This paper	+0.11	0.083	high-res sp.
Twarog et al. (1997)	+0.09	0.11-0.12	DDO
Anthony-Twarog & Twarog (2000)	+0.077	0.086	Strömgren
	+0.115	0.099	Strömgren
Meibom et al. (2002)	+0.12	0.10	CMD (Yale)