Recommended Resolution
This article explains the recommended resolution for printing projects.
Resolution is measured in ppi (pixels per inch) when talking about images on a screen, or dpi (dots per inch) when talking about printed images. The images below have been zoomed in to simulate how they will look when printed.
High Resolution Images (Recommended Resolution for Printing)
For printing, the recommended resolution for all images and art files is 300 dpi. The offset press cannot accurately reproduce resolutions above 300, so it is the industry standard.
note: submitting files at a resolution higher than 300dpi does not improve print quality, and beyond a certain point it makes the files too large to process easily. For this reason, PrintNinja sets a maximum resolution of 400dpi for submitted files.
The image of Billy the dog to the right is 300 dpi
Medium Resolution Images
Sometimes, the only images or art files available are under 300 dpi. If your images or artwork are in the 200 dpi-300 dpi range, they will still look pretty good, although not quite as sharp as images at a full 300 dpi.
The image of Billy the dog to the right is 200 dpi
Low Resolution Images
Images with less than 200 dpi resolution are considered low resolution, and they will exhibit notable pixelation / blurring in the final printed product.
The image of Billy the dog to the right is 72 dpi
Images used on the internet are typically 72 dpi. This is a suitable resolution for websites since it enables a small file size and does not look visibly pixelated on most computer screens.
However, images at 72 dpi will ALWAYS look pixelated and low-resolution when printed.
Why 300 DPI?
The 300 DPI standard isn’t arbitrary — it’s rooted in the physics of how offset presses reproduce images and how the human eye perceives detail.
In offset lithography, continuous-tone images (photographs, gradients) are reproduced using a halftone screen — a grid of tiny dots that vary in size to create the illusion of tonal range. The standard halftone screen ruling for commercial printing is 150 lines per inch (lpi), specified in ISO 12647-2:2013 (the international standard for offset printing on coated and uncoated paper).
The rule of thumb is that image resolution should be 2x the halftone screen ruling. At 150 lpi, that’s 300 dpi — enough pixel data for the RIP (Raster Image Processor) to calculate accurate halftone dots without visible artifacts. This 2:1 ratio is documented in Adobe’s print production guidelines and is the standard taught in graphic design programs worldwide.
Resolution by Project Type
Different types of artwork have different resolution requirements:
| Artwork Type | Recommended DPI | Why |
|---|---|---|
| Full-color photographs | 300 dpi | Industry standard — matches 150 lpi halftone screen |
| Color illustrations / paintings | 300 dpi | Same as photographs — continuous tone artwork |
| Black-and-white line art | 600–1200 dpi | Line art has hard edges with no anti-aliasing; lower resolutions produce visible jaggies (stairstepping) |
| Comics (inked line art + color) | 400 dpi | Higher than photos to keep line edges sharp; 600 dpi for pure B&W comics |
| Text rendered as images | 600+ dpi | Text edges are extremely sensitive to resolution. Better yet: keep text as vector (in InDesign/Illustrator) whenever possible. |
PPI vs. DPI: What’s the Difference?
These terms are often used interchangeably, but they describe different things:
- PPI (pixels per inch) — Describes the density of pixels in a digital image. This is what you set in Photoshop and what you should be checking when preparing files.
- DPI (dots per inch) — Describes the density of ink dots a printer physically places on paper. A 2400 dpi printer creates much finer dot patterns than a 300 dpi image requires, which is why submitting at higher than 300 ppi doesn’t improve output.
- LPI (lines per inch) — The frequency of the halftone screen used to reproduce images in offset printing. Commercial printing typically uses 150 lpi; newspaper printing uses 85 lpi (which is why newspaper photos look coarser).
In practice, when someone says “300 dpi” for a submitted file, they mean 300 ppi. The distinction matters technically, but the industry uses “dpi” as shorthand for both.
WARNING: Don’t Upsample
It may seem like a good idea to open up your artwork in Photoshop and just change the resolution setting from 72 dpi to 300 dpi. However, this doesn’t actually increase the resolution in your artwork, it just makes the pixels in the pixelated image larger. This is called upsampling, and while these images will technically read as 300 dpi once you expand them, they will still look just as pixelated / blurry on the printed page.
How to Check and Set Resolution
In Adobe Photoshop
- Open your file and go to Image → Image Size
- Check the Resolution field. It should read 300 pixels/inch.
- If your image is high-resolution but set to 72 ppi: uncheck “Resample,” then change the resolution to 300. The pixel dimensions stay the same — only the print dimensions change (the image will print smaller but at full quality).
- If your image is genuinely low-resolution (few pixels): no amount of resampling will add real detail. You’ll need a higher-resolution source file.
In Adobe InDesign
- Go to Window → Links to open the Links panel
- Select any placed image and check the Effective PPI column. This accounts for any scaling you’ve done in the layout — an image that’s 300 ppi at 100% becomes 150 ppi if you scale it to 200%.
- Use Preflight (Window → Output → Preflight) to flag all images below your target resolution automatically.
PrintNinja Tip
Make sure your files are no larger than 400dpi. Our printing machines cannot print over 400dpi. Submitting a file with a higher dpi may delay your electronic proof, as it takes longer for our prepress reps to download files of that size.
File Size and Resolution
Higher resolution means dramatically larger file sizes. Here’s how resolution affects file size for a standard 8.5″ x 11″ page:
| Resolution | Pixel Dimensions | Approx. File Size (TIFF) |
|---|---|---|
| 72 ppi | 612 x 792 | ~1.4 MB |
| 150 ppi | 1275 x 1650 | ~6 MB |
| 300 ppi | 2550 x 3300 | ~24 MB |
| 600 ppi | 5100 x 6600 | ~96 MB |
File size scales with the square of the resolution — doubling resolution quadruples the file size. This is why submitting at 600 dpi when 300 dpi is sufficient creates unnecessarily large files that slow down uploads, proofing, and prepress processing.
How to Rasterize Complex Vector Graphics in Adobe Illustrator
Sometimes artwork composed of many complex vector graphics cannot be processed properly for proofing. If this applies to your artwork, your prepress ninja will request that you resubmit your artwork with the complex vector graphics rasterized. The following guide will walk you through how to make that adjustments in Adobe Illustrator:
Without making a copy, you can select the vector artwork and choose [Effects > Rasterize] from the top navigation bar. You should select “Color Model: CMYK” (or “RGB”/”Grayscale” depending on the working color space of the document) and “Resolution: High (300 ppi)”. You can leave the other settings as default or make adjustments if you’d like, then click “OK”.
Now, because the rasterization has been applied as an effect, you can turn it on or off, change the settings, or delete it in the Appearance panel [Window > Appearance] at any time.
Vector vs. Raster: When Resolution Doesn’t Apply
Vector graphics — artwork created in programs like Adobe Illustrator using mathematical paths rather than pixels — are resolution-independent. They can be scaled to any size without quality loss because there are no pixels to enlarge. Logos, icons, line art, and typography should always be kept in vector format when possible.
Vector files are typically saved as .ai (Adobe Illustrator), .eps (Encapsulated PostScript), or .pdf (with vector data preserved). When exporting a final print file as PDF, vector elements remain sharp at any output resolution — only raster (pixel-based) elements in the file are subject to the 300 dpi requirement.
The PDF/X-1a standard (defined in ISO 15930-4) is the recommended export format because it preserves vector data, embeds fonts, and enforces CMYK color — producing the most reliable print output.