Using Lightroom with high-quality RAW photos (300 dpi) and editing a photo from there to photoshop (editing in photoshop), I automatically lower the quality to 240 dpi.
How do I solve this problem?
It's no use editing in Photoshop if I download the dpi.
The ppi value is optional metadata used by printer drivers to calculate the dimensions of a print. (Pixel dimensions divided by ppi = print size in inches)
Ppi has nothing to do with image quality, the important numbers are the pixel dimensions.
You can change the ppi value that is assigned when using Edit in Photoshop by going to Edit > Preferences > External editing > Resolution in Lightroom.
No matter what number you enter here, the pixel dimensions are still the same, and the image has not changed at all.