It is narrated from Sayyiduna Abdullah bin Umar (may Allah be pleased with him): "A woman whose husband has died should not apply kohl, nor apply perfume, nor use dye (khidab), nor wear dyed clothes, except black clothes; and she should not spend the night in anyone else's house, but she may visit during the day."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب العدد / 15535