MZSoft Studio
How to Enlarge a Small, Soft Old Photo 2× or 4× After Colorizing (HD Upscale)
HD Upscale (Pro) runs a super-resolution model on the colourised result at 2× or 4×. The final size is capped by your iPhone's memory (2560 to 4096 px on the long side), and the editor shows the real result size before you start. It adds plausible detail; it does not recover true detail.
The problem
An old print scanned small, or a wallet-sized photo, looks fine on a phone and falls apart when you try to print it or crop in on a face. A normal resize just stretches the pixels, which gives you a bigger and blurrier picture.
What HD Upscale does
After colourising, you can run the result through a super-resolution model (Real-ESRGAN) at 2× or 4×. It works in small overlapping tiles and blends them, adding plausible fine detail instead of just stretching.
It’s a Pro feature and runs entirely on the device.
How big can it go?
How large the result can be depends on how much memory your iPhone has, because the whole enlarged image has to be held while it’s built:
| Device memory | Maximum long side |
|---|---|
| 8 GB or more | 4096 px |
| 6 GB | 3584 px |
| 4 GB | 3072 px |
| 3 GB or less | 2560 px |
Your input is shrunk first if needed to fit. The editor shows the actual output size before you commit, because a 4× that gets capped back to a smaller factor on an already-large photo isn’t worth waiting for.
Steps
- Colourise the photo.
- Open the HD Upscale option in the result page (“Sharpen and enlarge your colorized photo”).
- Pick 2× or 4× and read the size it will produce.
- Run it. A progress percentage shows while it works.
- Compare faces and save.
Be realistic
- It invents plausible detail, it doesn’t recover what was never captured. Faces can look slightly smooth or “painted” at 4×.
- No second pass. An upscaled project won’t offer upscaling again.
- Use it where size matters: prints, crops and large screens. For social posts, skip it.
- Pro only, and the final size depends on your phone.
FAQ
Is HD Upscale free? No, it is part of ReColor Pro.
How big will the result be? It depends on your iPhone’s memory: the long side is capped at 4096 px on 8 GB devices, 3584 on 6 GB, 3072 on 4 GB and 2560 on 3 GB or less. The editor shows the real size before you commit.
Can I upscale twice? No. A result that was already upscaled isn’t offered again, because running it on its own output compounds the smoothing instead of recovering detail.
Is it uploaded? No. The upscaling model runs on the device.