I have downloaded this free photo.
I want to use it in a brochure, but I realized that there are some weird grey lines in front of the tower. Can you remove them? I'd highly appreciate it.
First of all I thought it was some sort of watermark as it looks so uniform - but looking closer I think (and I am no expert) that the marks are as the result of the removal of some sort of clinging plant (such as Ivy).
BTW the version you posted is only 465 x 700 pixels. That is probably not going to be a big enough image to use effectively on the front of a brochure. By using tineye reverse image search ( https://www.tineye.com/ ) I found a site where you can download the same image at 2000 x 3008 (might even be where you got it from in the first place). The image is here https://pixabay.com/th/เซบีญ่า-อันดาลูเซี-เซบียา-974242/ .
You have to register but it is free.
*EDIT Post crossed - JJLAPIN that is amazing. Well done.
Hey John, I was at first thinking about a moire effect due to the regular pattern of the bricks but the grey pattern wasn't regular, so probably no moire.
I used color range to correct it but JJLAPIN beat me to it...
And as you stated, a bigger free one is available.
The pattern on the bell tower is Moiré due to the brick pattern relative to the relatively low resolution of the Nikon D40 with which the image was taken.
The color brush with the layer set to Color Blend is an excellent cure. There still is a little bit of luminosity striation left over that would be easy to overlook so additional correction is optional for this image.
Here is a GIF animation that shows the difference with and without correcting for the luminosity portion of the Moiré. Subtle yet it is there. Just another option and again, there are some images with Moiré where fixing the luminosity part is not so subtle.