We say:
Shall I write in ink or in pencil.
Why not say:
Shall I write in ink or in a pencil?
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Sign up to join this communityWe say:
Shall I write in ink or in pencil.
Why not say:
Shall I write in ink or in a pencil?
In this context, 'pencil', like 'ink', is a material. You can use in with materials, but it wouldn't make sense for something to be in a pencil. 'A pencil' refers to the tool, and so one uses 'with' i.e. with a pencil.
If an English person said write in a pencil, I would understand 'a pencil' to mean "a particular type or colour of the material 'pencil'". In the same way, one can 'write in an ink', but this sounds more normal than 'in a pencil'.
Graphite is the material used in pencils, but is never used when referring to a writing format. Instead, we use "pencil". You would use "in a pencil" as follows: "What qualities are you looking for in a pencil? I want it to be medium hardness with an eraser."