I tried photoshopping and I got the color down, but I couldn't restore the boldness of it. It got transparent looking, because that is how I did it. I played with the transparensy and color offset of the pictures. What am I doing wrong or leaving out?
Instead of lowering the opacity of the Marks, you instead leave them both at 100% and change the "Blending Mode" of the top mark (I usually put the darkest mark on top for best results).
In most of my marks I use Hard Light, but I glance through all of the blending mode options to find the one that I like best.
Then I go to Image-->Adjust-->Hue/Saturation to adjust how I want it to look.
After that I go to Image-->Adjust-->Brightness/Contrast to provide some final touches.
I repeat that with the other layers until I'm satisfied with how it looks.
Then, if at the end one mark doesn't show up as well, I duplicate that layer, put it on top, and set the blending mode to "Soft Light". I lower the Opacity of that layer until I get it to look just right.
Anyways, this is my quick tutorial on how I did my mark merges, hopefully you can find it useful.