Positive photoresists and associated processes for microlithography in the ultraviolet (UV) and violet are disclosed. The photoresists comprise (a) a branched polymer containing protected acid groups and (b) at least one photoacid generator. The photoresists have high transparency throughout the UV, good development properties, high plasma etch resistance and other desirable properties, and are useful for microlithography in the near, far, and extreme UV, particularly at wavelengths less than or equal to 365 nm.