I'm trying to design an icon which will be mixed of two different icons. for example, a camera icon and video icon together in one single icon.
Are there any design principles, ideas or links for references how to mix icons? I couldn't find any on google search.
Many good questions generate some degree of opinion based on expert experience, but answers to this question will tend to be almost entirely based on opinions, rather than facts, references, or specific expertise. If this question can be reworded to fit the rules in the help center, please edit the question.
when talking about icons, the UX design principles focus on creating / choosing the right icon for a given use case, not how the icon is created (whether or not it is mergerd / combined / mixed from 2 existing icons or created from scratch), see e.g. http://boxesandarrows.com/optimizing-ui-icons-for-faster-recognition/
though you can try to search for overlay two icons instead of "mix", e.g.:
if you want to know how to combine 2 images, see tutorials about layers in graphics software, e.g. https://photo.stackexchange.com/questions/5398/how-to-create-two-layers-in-gimp-and-merge-them-back-into-one
