I propose a similar method as
@Isac but branching off after Step 3.
1. Open the image in Photoshop and make a duplicate of the background layer. Hence, you will have Layer1.
2. Add a new layer on top of the Background layer but below Layer 1 and fill it with White colour. It will be called Layer 2.
3. Click on Layer 1 and add a Brightness/Contrast layer to it. Now, clip this Brightness/Contrast layer with Layer 1. Also slide the Brightness value to left most value, that being -150.
(So far, the steps are exactly the same as
@Isac's post above.)
4. Add a layer mask to Layer 1. Click on the Layer mask of Layer1. (It is selected by default after its creation)
5. Go to Image>Apply Image...
6. Ensure your settings are these:
Source: No change
Layer: Merged
Channel: RGB
Tick the Invert checkbox.
Blending: Multiply
Opacity: 100%
Keep Mask Checkbox unchecked.
Select Ok.
7. You will find that the Blue lines have reduced drastically. Now, either delete Brightness/contrast layer or move the Brightness control between -60 and -10.
8. If you now make the White layer - Layer 2 - invisible (assuming the Original Background Layer is invisible), you will see that the text and pictures are on a transparent background. This separation of images+text from the background effectively reduces the blue lines. (Drawback is that the text may look light now. This can be corrected by increasing Brightness value between -60 and -10.)
9. At this stage, merge all the layers Viz White Layer 2 + Layer 1 along with its mask + Brightness/Contrast clipping mask layer (if you have not deleted it in Step 7).
If working with multiple pages, just make an Action of the above process to save time.
If any of the steps is unclear, just ask.