Smart object is losing quality when upscaled

Question

I have made an icon using shapes, with 72 ppi, and when I turn the layers into a smart object, and then change the resolution to 144 or 300 ppi, its losing quality. But the shape layers and text that are not converted into a smart object, regardless of scaling the resolution up or down, retain the crisp quality. So what's making the smart object to lose its quality?

Thank you.

The top icon has not been converted into a smart object.

and the icon below is converted to a smart object which he quality degredation is obvious.

Answer 1

I don't think what you are trying to do will work. The problem is that when you put vector layers into a smart object, the vector layers within the smart object will be rendered as a raster image in the main document. Even though the vector layers themselves inside the smart object can be rescaled without blurring/degradation, the same is not true of the smart object itself.

There are a few ways you could work around this limitation

1. Don't use a smart object to begin with. Instead duplicate the icon group, and scale up the group to make it slightly bigger than what you need, then convert it to a smart object. As long as you don't scale it up, other transforms should work reasonably well without too much degradation in quality. Note that really thin lines could be an issue here for example if you scale down too much.

OR

2. Open the smart object you already have (double clicking will open it for editing), and increase the Image size using Image > Image size (with resampling enabled), and increase the pixel dimensions, then save and close the smart object. This will in effect increase the resolution of the smart object back in the main document.

OR

3. Create your vector artwork in Adobe Illustrator instead of Photoshop, and save as an AI file, which you can then place in Photoshop as a smart object. When you rescale a true vector smart object, it should not cause these issues at all.