Thank you so much Dinasset. I take note about treatment. I like the results.

These photos from my last journey to Lisbon. They belong to Cathedral Cloister. I tried to reduce some noise to one of them.

And these,

Nice pictures, but I don't think it's a good idea to apply de-noising: first image has been "damaged" IMHO

Thank you Dinasset, Apply on it other kind of filter better?

Yes, I like to see details on architectures.
My first trial on that subject:
1-gimp-color-levels auto on values
2-gimp-color-levels mid-point to 0.80 only on BLUE
3-gmic-sharpen-richardson/lucy 1.1 11

Thanks Dinasset for sharing your steps to follow, you gave the pic that look I saw in real atmosphere.

in this second one i stretched all colors (no modifications on blu) and luminosity
(giving 1% of min/max values on any color and values)

...I'm sure someone will come with nicer outcomes...if they are not all in the sea to get some fresh on the skin (here is terribly hot!)

I see. I like more your first way as it isn't bluish however your second try is more real to the original colours. But both of them I like a lot and I learn to know how to treat the photos. Thanks
and... about hot, here it's boiling I can't go out, so under air conditioner almost the whole day.

still second method, but reducing a bit the blueish