Hi eCommera.simona.georgieva, I am not sure how automated you would like this process to be, but this is certainly a solution to help you move forward. It certainly will take less time than continuing to look in my opinion: 1. With your InDesign CC(2014) document open, click on the Pages panel and double click on your Master Page (or multiple Master Pages that you have applied to the pages within your design) 2. Create a New Layer on each Master Spread you have applied to the document and name it something obnoxious like DO NOT PRINT, or something like that. 3. Simply draw a vertical line in the gutter of the Master Spread on your New Layer. 4. Change the line Stroke to something thicker like 2 points, maybe keep it at 1 point. 5. Export your PDF as spreads. 6. Turn the newly created Layers off in InDesign CC(2014). 7. Resave the document so that it opens in its original state.
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