Did you draw those lines on a separate layer that can be deleted?
Next time, consider that or using guidelines, that's what they're there for.
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Thanks for replying, I may not have explained my problem correctly. The watercolour is an image I drew with pencil on paper and then painted. It was not created in Photoshop. I cannot see the lines on my original image, nor on Photoshop, but I can see them when I print the image. I have printed it on two different printers so it is definitely my rubbed out lines that are coming through. I was hoping that there would be some way of enhancing the picture on Photoshop to bring out these lines. I am a beginner with Photoshop, so I have no idea of how to do this.
One thing you might try. In PhotoShop, open the Channels Pallet (see below -- my file is in RGB). Turn off the RGB (or CMYK) overview (click on the eye sumbol). Then, one at a time, view each channel separately to see if they show up on any one channel more than others. Failing that, try combinations of channels.
If they are printing, then they are there in Photoshop.
Then, one at a time, view each channel separately to see if they show up on any one channel more than others.
That's a good idea. Also, make sure you are viewing your image at 100% in Photoshop (View>Actual Pixels) to make sure the lines are not being obscured from interpolation to screen pixels.