Your sequence is SD resolution, your export is HD resolution; hence the blurriness.
Mhh.. Ann might be right but it doesn't sound logic. If its sharp in sd why should it become (that) blury in hd?
Also it looks not just blury but badly compressed.
Just recently I discovered that exporting an animation via Media Encoder created very bad results but direct export from Premiere was way better (with the same settings applied). Sounds strange too, but worth a try I think.
I noticed that the sequence your are exporting, the source, is using video fields. I think this might be part of the problem. How did you create your stills; in what program and what format are you using to export them to Premiere? You might want to change your sequence settings to Progressive, under Sequence/Sequence settings...
I created the frames in ms paint, and they are .pngs
Also it hasn't been going through Media Encoder, I think it's just being exported by premiere pro.
Would reinstalling media encoder possibly solve this?
No point reinstalling.
Upscaling means things get blurry.
If you want 1920x1080 output it means the source and sequence needs to be 1920x1080 also.
Then you should definitely set your sequence settings to Progressive. But as Ann says; upscaling will make it look blurry no matter what.
Thank you!! It looks much better now