Full Idea
The power to produce any idea in our mind I call 'quality' of the subject wherein that power is.
Gist of Idea
A 'quality' is a power to produce an idea in our minds
Source
John Locke (Essay Conc Human Understanding (2nd Ed) [1694], 2.08.08)
Book Reference
Locke,John: 'Essay Concerning Human Understanding', ed/tr. Nidditch,P.H. [OUP 1979], p.135
A Reaction
This strikes me as much the most accurate way to think of properties, but then I accept Locke's distinction between primary and secondary properties. Red is a property of brains, not of tomatoes. Tomatoes have power to cause this property.
Related Idea
Idea 3757 Causal theory says true perceptions must be caused by the object perceived [Bernecker/Dretske]