The page title font styles including color are set in 

VamTam > Styles > General Typography > H1. 

These styles are general for all pages and posts.

Please note that if you set a page title area background color then the title font color is no longer coming from the H1 setting in 

VamTam > Styles > General Typography > H1.

 It is derived from a formula based on the title area background color in order to be readable in both dark and light versions.

When the Page Title Background is set to a dark color, the Page Title font color becomes bright and vice versa.

In case that the Page Title Background is set to an image, it's necessary to set the Page Title Background according to the image colors to make it readable.

You can set the Page Title background color and thus changing the Page Title color in two places:

1. General theme settings

Dashboard > VamTam > Styles > Header > Page Title Background. 

This setting is global and will affect all pages and posts.

2 Local page/post Vamtam options

Please note that in the example below we've set the background image and also the  Page Title Background  is set to dark color in order to have whitish font color over the image.