Methods and apparatus are provided for selectively heating blood vessels in a patients skin to effect a desired dermatological (medical or cosmetic) treatment. For shallow vessels, particularly plexus vessels and superficial vessels/veins, radiation is applied to the vessels involved in the treatment which includes substantial radiation in a blue band of approximately 380-450 nm. The invention also involves maximizing the radiation used for which the safety radio for the area being treated is greater then one and minimizing the radiation used for which the safety ratio is less then one. This generally involves, depending on the blood vessel involved in the treatment and the patient's skin type, using radiation in one or more of a blue, green-yellow and near infrared wavelength band and filtering out radiation at other wavelengths, including radiation between the wavelength bands used.