Why are my files losing quality when I reopen them?

[StudioPhi]

I've been working on a design that I'm trying to clean up from enlarging it and I've noticed that when I open it again to work on it the quality has dropped and it no longer looks as clean. Why would it not open in the same quality that it was in before?

[John T Smith]

Please post the name of the program you use so a Moderator may move this message

-A program would be Photoshop or Dreamweaver or Muse or Premiere Pro or ???

[StudioPhi]

Ooops, sorry, I'm using photoshop.

[John Waller]

Moved from Creative Cloud forum.

Which operating system? What file format are you using?

[StudioPhi]

I'm using macOS Sierra 10.12.6, 1.4GHz Intel Core i5, 8GB 1600MHz DDR3, Intel HD Graphics 5000 1536 MB.

The file formats have been jpg, psd, and psb.

The version of Photoshop is CC 2018

[D Fosse]

Jpegs will deteriorate with every resave. That's the price for the massive reduction in file size.

PSD/PSB and TIFF are non-destructive formats that will not change a single pixel.

To view any file accurately, in any application, you need to view it at 100% - one image pixel represented by one screen pixel.

[StudioPhi]

So that still leaves me asking the questions as to why my psd or psb files are losing quality when I open them up again to do some more work. What I'm noticing is that the edges of things are getting an odd looking graininess to them.

[D Fosse]

StudioPhi  wrote

What I'm noticing is that the edges of things are getting an odd looking graininess to them.

What you describe there sounds very much like jpeg artifacts. There's no way this can happen with psd or psb - unless:

Is this a Smart Object containing a jpeg that is being repeatedly resaved?

[StudioPhi]

Nope it's a regular photoshop file with layers.

[StudioPhi]

I also noticed that when I opened the jpg in Preview it was showing a better quality image than Photoshop.