Upscale Low-Resolution Artwork

Customers send you low-resolution files all the time — screenshots from Instagram, phone photos of sketches, images saved from websites. These are usually 72 DPI and look terrible at print size. PrepOS can fix that.

When you need to upscale

A quick rule of thumb:

• Print size × 150 DPI minimum = the resolution you need
• A 10" wide print needs at least 1500 pixels wide
• A 12" wide print needs at least 1800 pixels wide

If the customer's file is smaller than that, you need to upscale.

Step 1: Check the artwork analysis

Upload the file in PrepOS. The Artwork Analysis immediately tells you:

• Current pixel dimensions
• DPI at the intended print size
• Whether it needs upscaling

Example: Customer sends a 600×600 pixel image. They want it printed 10" wide. That's 60 DPI — way too low. You need at least 150 DPI (1500 pixels) for a clean print.

Step 2: Choose your scale

Click Upscale and select:

• 2x — doubles the resolution (600px → 1200px)
• 4x — quadruples the resolution (600px → 2400px)

For our example: 4x takes it from 600px to 2400px. At 10" print size, that's 240 DPI — perfect.

Step 3: AI processes the image

PrepOS uses AI (Real-ESRGAN) to intelligently upscale:

• Edges stay sharp (no blurry enlargement)
• Detail is preserved and enhanced
• Text remains readable
• Colors stay accurate

This takes a few seconds depending on file size.

Step 4: Review the result

Compare before and after:

• Zoom in to check edges and fine details
• Look at text (if any) for clarity
• Check that colors haven't shifted

If it looks good, you're done. The upscaled file is now your working file.

Step 5: Continue with prep

After upscaling, you'll often still need to:

• Remove the background (if it has one)
• Clean up edges
• Apply halftones (if printing on dark)

Do those steps in PrepOS as normal — the upscaled file handles them better because it has more pixel data to work with.

What AI upscaling can and can't do

It can:

• Sharpen blurry edges
• Enhance fine lines and details
• Make text more readable
• Increase resolution without the "pixelated" look

It can't:

• Invent detail that was never there
• Fix heavily compressed/artifacted JPEGs perfectly
• Make a 50×50 pixel image print at 14" (there are limits)
• Replace vector artwork (if the customer has an SVG or AI file, ask for it)

When to ask for a better file

If the source file is extremely low resolution (under 200px on any side) or heavily compressed (visible JPEG artifacts), upscaling can only do so much. In these cases:

1. Try upscaling anyway — sometimes it's surprisingly good
2. If the result isn't clean enough, ask the customer: "Do you have a higher-resolution version of this file? The one we received is very small and won't print cleanly even with enhancement."

Tips

• Always upscale before background removal — more pixels = cleaner edge detection
• Check at 100% zoom — don't just look at the thumbnail. Zoom to actual print size to judge quality.
• 4x is usually enough — going from phone-quality to print-quality rarely needs more than 4x
• Vector is always better — if the design is a logo or text, ask if they have it in vector format (SVG, AI, EPS). Vector scales infinitely without quality loss.