Hi Piotr, Original photo taken with flash, two boilers in a dark dungeon with dim light. Duplicated image, used combination of filters, stylize/Find Edges/set levels/convert to B&W and then mask this copy and blend into original coloured version. Play with Hue/Saturation and colour control to enhance required colours and selectively erase to varying degrees until required texture is established. Took me 12 to 20 hours of PS work to complete this image. But I was learning as I worked. ~ Bob