Sometimes it is useful to use a negative value.

[romankrebs]

react-scroll-parallax/src/utils/propValidation.js

Lines 38 to 42 in 9bc2b3b

	return value >= 0
	? null
	: new Error(
	`[${propName}] in ${componentName} is less than zero. [${propName}] must be greater than or equal to zero.`
	);

I have to make a monkey patch to remove restrictions when using negative offsetMax values. Perhaps we remove these limits?
I can do PR :)

[jscottsmith]

You can use the slowerScrollRate prop, it internally flips the values which is probably what your are trying to achieve. I won't do this in the next version because it's confusing, but leaving it as is for now. Thanks.