Qualifications improve your chances; they do not gate the job. Level 6 is the most recognised.
Level 6 most recognisedOpen entry
Your route in
You can start without qualifications - direct entry/volunteering; a qualification improves your chances
1
Qualifications employers recognise (Level 6)
Any of these strengthens your application.
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Where this can take you
If you work freelance, you'll need to build up and maintain a client base. You can use your illustrating skills in a variety of sectors including: advertising, fashion and merchandising, publishing and websites and computer games. With further training and experience you could specialise as a medical illustrator or scientific illustrator. You could also move into teaching.