How to Change Color of Certain part of a Texture

Question

I downloaded a generic model of a shoe that had a base texture, normal map, and roughness associated with it. On the base texture the shoe is either black and white. I was wondering if I could section each part of the base texture to change the color. I wouldn't be to do it in Photoshop because the texture is mostly just black and white and it would change all blacks or whites instead of sectioning off each part. Here's a picture of an example of how I would like to change the color:

How would I go about just changing the selected mesh to a different color such as red while still keeping the base texture?

Answer 1

In this example the Voronoi Texture node is standing in for your image texture -- note that the Texture Coordinate is Suzanne's UV map.

In the pics above I've added a Material Slot (Properties Editor > Material Properties tab > Add Material Slot), then added Suzanne.Material.001 to the slot and duplicated it (Properties Editor > Material Properties tab > New Material), creating Suzanne.Material.002.

In the pic above, in Edit mode I've selected the faces I want to be redder and Assigned them to the second Material Slot (Properties Editor > Material Properties tab > Asign button [while the second Material Slot is selected]).

In the pic above a Mix RGB Node has been added after the texture node. You see this blends the colors of the texture (Color 1) with red (Color 2), using one of several Blending Modes (in this example, Linear Light). How much of Color 1 is blended with Color 2 depends on the Factor. You should experiment with the settings to see what comes closest to the effect you're trying to achieve.

Blend file link here.