Uvby-beta photometry of stars in the Michigan Spectral Catalogue. I - The Delta Del stars uvby-beta photometry of 74 stars classified as Delta Del in Volume 1 ofthe Michigan Spectral Catalogue is presented. The photometry is inagreement with the spectral classification in that it indicates DeltaDel stars are metal-line-enhanced stars with equivalent-temperaturetypes of A9 + or - 2 subtypes. There is a discrepancy between theluminosity implied from the delta c1 index and the spectralclassification. It is argued that c1 is an inadequateluminosity indicator for some late A- to early F-type stars. Several ofthe Delta Del stars are known Delta Scuti pulsators, and some commentson the metallicism-pulsation relation are made.
