In my opinion it’s best to do this to get the grains and pulp to stand out. So you want to play to have all those little spots to come up. If you go any further then your texture will turn into 3 color values
2. image - adjustment - hue/saturation
now, if you go too far with the saturation it might make the colors too harsh. If that’s the case just turn down the lightness.
two more bits of cardboard texture that tumblr wouldn’t let me upload with the rest of them. I tend to enjoy using the cardboard backing of notepads for texture. And then I will use layer effects in order to enhance the texture and the pulp of the cardboard. Increasing the levels, changing the hue and saturation, I’ll try to post up tutorials if you ask for any tips on these techniques. I’d be more then happy to see what you make of these. So please send a message how it turns out for you.