: Digitally "cleaning" spray painted graffiti I am working on a project where I have to "clean" spray paint in an image of a cave while retaining underlying writing. Take a look at the attached

@Kevin459

Rather than make this too complicated, such an edit can be made with fairly basic tools in Photoshop. This method needs no selections, with the added benefit that it would work for almost any colour of paint as long as it's not solid paint.


Use the Brush tool set to Color mode
Use the Eyedropper tool for sampling nearby colours colours
Paint over the blue/off-colour parts
Use the dodge tool to lighten the parts which are too dark
Repeat steps 2 to 3, until the spray paint is no longer visible.


Of course this is very manual method, some skill is required, and it takes a moderate amount of time.

Here's my result using those tools, showing before and after:

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@Shelton719

You cannot bring back anything which is made invisible by the cyan spray. One of them is the original surface color under the spray, that can only be guessed. Fortunately some brightness variations are still left. One easy receipe to try:


Make 2 copies of the image layer. Shut the original. (It's your spare, it's needed also for comparison when the fix is done). Let's call the copies TOP and BOTTOM according their places in the layer stack.
Goto TOP. With Image > Adjustments > Hue/Saturation > Cyans make the cyan color as unsaturated as possible. You do not actually need lightness slider, only the range sliders and Saturation.





Shut temporarily TOP, goto BOTTOM. With Image > Adjustments > Black and White find BW mix where all, but the sprayed text is visible:





With Curves tool lift up the contrast of the just made BW image:





Switch TOP layer on, give to it blending mode color:




The sprayed text is still visible as grey color. If this is unacceptable, we have still one trick.


Make a selection which covers well the sprayed text, but not much around it. Polygonal lasso tool goes well. Actually no selection is needed, if you allow the fine colored scratches elsewhere to lose their color, they will become grayscale.
Apply large radius Gaussian Blur to TOP layer. The color leaks to the sprayed area in the selection:




The last trick has 2 drawbacks. In the selection all fine scratches become black and white. In addition the selection is needed. All other steps need no selections. They still cannot be automated, because the sliders must be adjusted by eye.

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