Just as an FYI Testors model paint is a good option. 

I have used it on my bike and was able to match every color on my Trek (Dnister Black - Testors Graphite Black Metallic, Viper Red - Testors Gloss Red, Gloss Black, Flat Black). Fortunately, I have only had to use it on a few pencil tip size nicks. You can find it at most craft stores in the US like Michael's, Hobby Lobby, etc for less than $5.00.

I have found usually a cheap precision paint brush - https://amzn.to/2KuUSFr, a steady hand, and a bit of patience can result in some really good results. 

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  [1]: https://i.sstatic.net/rz9jt.jpg
  [2]: https://i.sstatic.net/0npx6.jpg