Texture build up

In order to further build up my texture I found one of the dirt texture reference photos that I took and began to play around with it in photoshop. I first needed to darken it so that it looked convincing, to do this I duplicated the layer and changed the blending mode of the layer above to multiply. This darkened the image and also made the colours appear more saturated. After I had the texture I wanted I needed to apply it to the actual asset texture, to do this I created a layer mask and began to 'erase' sections of the image. I found a custom brush online that created a good natural spattered effect, making the dirt appear as though it had been caked on during operation.

Finally I used this brush at a series of varying opacities to create a gradual gradient and still retain adequate texture detail.