How to remove contrast from recaptcha?

Question

I know the idea is to make the text somehow hard to read for the users but still they complain and I've seen how the control used here in stackoverflow doesn't have the dark circles contrasting with the text in recaptcha.

How can I replicate this?

Thanks.

Answer 1

You can't.

If you want more control over how the CAPTCHAs are generated, you may want to take a look at different library.