Low resolution is a problem you cannot fix by upscaling — but there are practical steps you can take to produce a print-ready result, and knowing which of those steps actually apply to your situation saves a lot of wasted effort.
Step 1: Identify Which Images Are Low Resolution
Use PrintReady247 to scan your PDF and get an instant list of all images below 300 DPI, including their location in the document. This matters more than it sounds — in a multi-page document, manually checking every image by eye is slow and unreliable, since a low-resolution image can look deceptively sharp when previewed small on screen. An automated scan flags the exact problem images and their page location, so you know precisely what needs fixing before you start.
Step 2: Find Higher-Resolution Versions
Check your original sources:
- Original photo files from your camera or phone — most cameras and modern phones capture at far higher resolution than what typically ends up in a document; the low-resolution version usually crept in during a resize, compression, or export step somewhere along the way.
- High-resolution downloads from your stock image provider — many stock sites offer multiple resolution tiers; make sure you originally downloaded (or re-download) the largest available size rather than a web-preview version.
- Vector source files (AI, EPS, SVG) for logos and illustrations — logos are very often available as vector files even if you only have a small raster (PNG/JPG) copy on hand. Check with whoever originally designed the logo, or your company's brand asset library.
- Cloud photo libraries and backups — Google Photos, iCloud, and similar services often retain the original full-resolution upload even if a smaller version was shared or downloaded at some point.
Step 3: Replace in the Design File
Open the original design file, replace the low-resolution images with the high-resolution versions, and re-export the PDF. When replacing, check that the new image is placed at (or close to) 100% scale rather than being stretched significantly larger — even a high-resolution image loses quality if it's scaled up far beyond its native size in the layout.
What "High Enough" Actually Means for Your Print Size
Not every image needs the same resolution — the requirement scales with how large the image will actually print. A rough guide: for standard print at typical reading distance (flyers, brochures, business cards), aim for 300 DPI at final size. For large-format print viewed from further away (posters, banners, trade show displays), 150 DPI or even lower can still look sharp, because viewing distance naturally compensates for lower pixel density. Knowing this can save you from unnecessarily re-shooting or re-sourcing an image that is technically "low resolution" by the 300 DPI standard but perfectly adequate for how it will actually be printed and viewed.
What If You Only Have the PDF?
If you cannot access the original design file, your options are more limited, but not zero:
- Replace images using PDF editing software (Adobe Acrobat Pro) — this lets you swap out an individual image within the existing PDF layout without needing the original design file, though it requires locating a higher-resolution version of that specific image first.
- Use PrintFix247 to optimise what is available — automated repair tools can improve compression artefacts and sharpen perceived detail slightly, though this cannot recover genuinely missing resolution.
- Contact whoever created the original file — if the PDF was designed by someone else (an agency, a previous employee, a client), asking for the original source file is often faster than trying to work around a flattened PDF.
Be aware that genuine low-resolution images cannot be made sharper through software alone — the goal in this scenario is damage control: identify the issue early, decide whether the current resolution is actually acceptable for the intended print size, and source better originals wherever the answer is no.
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Check now →Common Mistakes When Fixing Resolution Issues
- Upscaling instead of resourcing — the most common shortcut, and the one that produces the least convincing result. Always prefer a genuine higher-resolution original over any upscaling tool.
- Fixing the PDF instead of the source file — patching a flattened PDF works, but if you have access to the original design file, fixing it there means future exports are automatically correct too, rather than needing the same manual patch every time.
- Only checking the images you remember placing — background images, texture fills, and imported logo files are easy to forget when manually reviewing a layout; an automated scan catches these too.
Prevention
Always check image resolution before placing images in your layout, rather than discovering the problem at the preflight stage. Set up a simple rule: if it came from a website, social media, or was screenshotted, it is probably too low for print and should be treated as unusable until you confirm otherwise. Building this check into your workflow from the start avoids the scramble to source replacement images right before a print deadline.
Frequently Asked Questions
How much can I safely upscale an image before it looks bad?
There's no fixed percentage that works universally — it depends heavily on the original image's detail and content. As a rough guide, upscaling beyond about 120–130% of the original size starts to show visible softness for most photographic content; simple graphics with large flat areas tolerate more.
Can AI upscaling tools genuinely fix low-resolution images?
They can improve the visual impression of sharpness for some image types, particularly photos with clear subjects, but they're generating plausible detail rather than recovering real information. Results vary significantly and shouldn't be relied on for anything brand-critical or text-containing.
Is it worth re-shooting a photo instead of trying to fix resolution in software?
If the option exists and the image is important, yes — a fresh high-resolution capture will always outperform any software-based fix on a low-resolution original.