How can I change the black lines in the paper under the pen to green lines like the photo below?
I don't know how to select the lines and recolor them green because part of them are out of focus.
I have the illustrator file used to print the paper. The lines are green in the ai file, but I only have a laser printer so I cannot print green.
I also have a simulated photo of the paper with green lines (done in after effects).
But taking a photo of the pen, even on a green screen, then keying it and pasting on top of the simulated paper is also not easy, because part of the pen (e.g. tip of case) is also out of focus and is difficult to key.
If I have a color printer this would be easily solved: just print the paper with green lines, put the pen on top and take a photo. But given what I have, what is the easiest solution?
you can actually adjust the colour of the black and white lines using an adjustment layer in Photoshop. Open the picture in Photoshop and check the Layer Panel: click on the "add adjustment layer" icon. There's several options here, but I think the "colour balance" or "hue & saturation" are the best option for what you want to achieve.
The pen will have a colour shift as well, so you will still need to work with the layer mask on the adjustment layer to only affect the areas that you want to adjust. Click on the Layer mask and colour the areas that should not be affected. That will take some drawing skills, but you can use tools like the blur tool for the areas that are out of focus.