Changing the generic text that is set on the page.

Hello i was wondering how i can change the text that is set on the page by the featured images, you know the images underneath the slider that display pictures and you can enter text underneath which tells your users about the page. Mine seems to be set on grey and i cannot find where to change it i am guessing there is a simple css code for it though, i need to change as my background is black and the grey writing does not show on this background. Thank you