Introduction
You found a beautiful old photograph tucked inside a shoebox — a wedding portrait, a family reunion, a childhood moment frozen in time. Now you want to print it large enough to frame and hang on the wall. The problem? That small, faded, scratched print or low-resolution scan looks nothing like what you imagined blown up to poster size. Before you send anything to a print lab, you need to prepare your image correctly. This guide walks you through everything: resolution requirements, AI upscaling, restoration, and file formats — so your final print looks sharp, clean, and worthy of the wall.
Resolution Requirements for Large-Format Printing
Resolution is the single most important technical factor when preparing a photo for large-format printing. Print labs measure resolution in DPI (dots per inch) — the number of ink dots printed per inch of paper. The higher the DPI, the sharper and more detailed the print appears up close.
Here are the standard benchmarks you need to know:
- 300 DPI — the gold standard for professional prints viewed at close range, such as portraits and framed artwork
- 200 DPI — acceptable minimum for large prints (24×36 inches or bigger) viewed from a few feet away
- 150 DPI — the absolute floor for oversized prints like banners or murals, where viewing distance is greater
What does this mean in practice? If you want a 16×20 inch print at 300 DPI, your image file needs to be at least 4,800 × 6,000 pixels. A photo scanned at 72 DPI or a heavily compressed JPEG from an old phone will fall far short of that. Simply stretching the image in editing software does not add real detail — it just makes the existing pixels larger and blurrier.
This is exactly why AI upscaling has become a game-changer for anyone printing old photographs.
AI Upscaling Explained
Traditional upscaling — sometimes called interpolation — works by guessing what color the new pixels between existing ones should be. The result is a bigger image that looks soft, blurry, or blocky, especially at large sizes. AI upscaling works on an entirely different principle.
Modern AI upscaling models are trained on millions of images. They learn to recognize textures, edges, facial features, fabric patterns, and fine details. When you feed them a low-resolution photo, they don't just stretch pixels — they intelligently reconstruct missing detail based on what those patterns should look like. The result is a larger image that holds up under scrutiny, even at print sizes that would have been impossible with the original file.
Fotki, an AI photo app for iPhone, includes a powerful upscaling tool built specifically for situations like this. You can increase an image by 2×, 4×, or even higher while preserving edge sharpness and fine texture. For old photographs — where the original resolution is almost always a limiting factor — this capability is essential. Fotki's upscaling engine is optimized for portrait and heritage photography, meaning it handles faces, skin tones, and analog film grain with particular care.
When using AI upscaling, keep one rule in mind: always upscale before you restore, or restore and then upscale — but never upscale a heavily damaged image and expect the AI to fix tears and stains as part of the process. Each tool does a specific job best.
Restoration Before Printing
Old photographs carry years of damage: fading, yellowing, scratches, water stains, torn edges, and dust spots. Printing an unrestored image at large format doesn't hide these flaws — it magnifies them. A small scratch that looks barely noticeable on a 4×6 print becomes a dramatic gash on a 20×30.
AI-powered restoration addresses these problems automatically and remarkably well. Fotki includes dedicated restoration features that handle the most common types of damage:
- Color correction and fading recovery — restoring natural tones that have shifted toward yellow or brown over decades
- Scratch and crease removal — identifying and filling physical damage without destroying surrounding detail
- Noise and grain reduction — smoothing out heavy film grain or scan artifacts while keeping important texture
- Face enhancement — sharpening soft or slightly blurred facial features, which matters enormously in portrait printing
The goal of restoration is not to make the photo look like it was taken yesterday. The goal is to make it look like the best possible version of itself — cleaned up, clear, and ready to be seen at scale.
Practical Workflow: Step by Step
Follow this sequence to take an old photo from damaged original to print-ready file:
Step 1: Scan at the Highest Resolution Possible
If you're starting from a physical print, scan it at a minimum of 600 DPI, ideally 1200 DPI for very small originals. Use a flatbed scanner, not a phone camera, whenever possible. This gives AI tools the maximum amount of original data to work with.
Step 2: Restore the Image in Fotki
Open the scanned image in Fotki and apply restoration. Fix color fading, remove scratches and stains, and use face enhancement if the photo contains portraits. Save after restoration but keep the original scan as a backup.
Step 3: Upscale with AI
Use Fotki's upscaling feature to bring the image up to the resolution your print size requires. For a 20×24 inch print at 300 DPI, you need roughly 6,000 × 7,200 pixels. Upscale accordingly and check the result by zooming in closely before moving forward.
Step 4: Export in the Right Format
Choose your file format carefully for the final export:
- TIFF — best choice for professional print labs; lossless compression, preserves every pixel
- PNG — good lossless option if TIFF is not supported; larger file size than JPEG
- JPEG — acceptable if saved at maximum quality (95–100%); avoid multiple re-saves, which degrade quality
When in doubt, ask your print lab what format they prefer. Most professional labs strongly recommend TIFF for archival and large-format work.
Frequently Asked Questions
Can I print a photo from a smartphone scan?
Yes, but with limitations. Smartphone cameras can capture decent resolution in good lighting, but they introduce lens distortion, uneven illumination, and moiré patterns on printed photos. A flatbed scanner produces more consistent and usable results. If a scanner isn't available, use Fotki to upscale and correct the smartphone scan before printing.
How much can AI upscaling actually improve a photo?
AI upscaling can realistically double or quadruple the linear resolution of an image while keeping it looking natural. An image that was only suitable for a 5×7 print can often be brought up to 16×20 quality. Results depend on the quality of the original — the more detail the source image contains, the better the upscaled result will be.
Does restoring an old photo damage the original file?
No — as long as you work on a copy and save your restored version as a separate file. Fotki processes images non-destructively, meaning your original scan remains untouched. Always keep the unedited scan archived separately before applying any restoration or upscaling.