With regard to Hazrat Abu Bakr’s (ra) appearance, Hazrat Aisha (ra) narrates that once, she was sat in her camel litter and saw an Arab man walking. Upon this, she stated, “I have never seen anyone resemble Hazrat Abu Bakr (ra) more than this person.” The narrator states that they asked Hazrat Aisha (ra) to describe the features and appearance of Hazrat Abu Bakr (ra). Hazrat Aisha (ra) stated, “Hazrat Abu Bakr (ra) had a fair complexion and was of a thin build. He had very slender cheeks and his back was slightly curved forward as a result of which his outer garment would slip down from his back. He had a slender face and deep-set eyes and he had a prominent forehead.”
(Ibn Saad, Al-Tabaqat al-Kubra, Vol. 3, Abu Bakr Siddiq (ra) wa man Bani Taym bin Murrah bin Kaab [Beirut, Lebanon: Dar al-Kutub al-Ilmiyyah, 1990], p. 140)
In Sahih al-Bukhari, there is a narration from Hazrat Abdullah bin Umar (ra) in which the Holy Prophet (sa) said, “Whosoever lets his clothes drag on the floor behind him out of arrogance, Allah the Almighty will not even glance at him on the Day of Judgement.” Hazrat Abu Bakr (ra) said, “My cloak from one side becomes loose and falls down, unless I pay special attention to it.” The Holy Prophet (sa) stated, “You do not do it out of arrogance.”
(Sahih al-Bukhari, Kitab Fada‘il Ashab al-Nabisa, Bab Qaul al-Nabisa Lau Kunta Muttakhidhan Khalilan, Hadith 3665)
Therefore, it was permissible for him as there was no harm in doing so.
Hazrat Abu Bakr (ra) would use Henna and Katam as a dye.
(Sahih Muslim, Kitab al-Fada‘il, Bab Shaibihisa, Hadith 6073)
Katam is a plant that grows on mountains. It is applied after mixing with indigo leaves [wasmah], which causes the hair to go black.
(Lisan al-Arab, Zair madah ‘Katama’