How to Convert Images for Print: DPI, Color Space & Format Guide

The Gap Between Screen and Print

An image that looks stunning on your monitor can look terrible in print. The colors shift, details become muddy, and fine text turns into an unreadable blur. This is not a printer problem -- it is a preparation problem. Digital images and printed output operate in fundamentally different color spaces, resolutions, and file format requirements.

Converting images for print requires understanding three critical concepts: resolution (DPI), color space (RGB vs CMYK), and file format (what your print service actually needs). Get any of these wrong and the results will be disappointing. Get all three right and your prints will match what you see on a properly calibrated display.

This guide covers the complete workflow for preparing images for professional print output, from business cards and brochures to large-format posters and photography prints.

Understanding DPI for Print

DPI (dots per inch) determines how many pixels are packed into each inch of printed output. Higher DPI means more detail and sharper prints, but it also requires larger source images.

DPI Requirements by Print Type

The DPI Calculation

To determine if your image has enough resolution for print:

Required pixels = Print size (inches) x DPI

Example: 8x10 print at 300 DPI
Width:  8 x 300 = 2400 pixels
Height: 10 x 300 = 3000 pixels
Minimum image size: 2400 x 3000 pixels (7.2 megapixels)

If your image has fewer pixels than required, you have three options:

1. Print smaller -- Reduce the print size until the DPI reaches 300
2. Accept lower quality -- 200 DPI is acceptable for prints viewed from a distance
3. Upscale the image -- Use AI upscaling tools, though results vary (see our guide on how to upscale images without losing quality)

For a deep dive into resolution and DPI, see our comprehensive image DPI and resolution guide.

RGB vs CMYK Color Spaces

This is where most people get caught off guard. Your screen displays colors using RGB (Red, Green, Blue) -- an additive color model where mixing all colors produces white. Printers use CMYK (Cyan, Magenta, Yellow, Key/Black) -- a subtractive model where mixing all colors produces (approximately) black.

Some colors that look vivid on screen simply cannot be reproduced in print. Bright neon greens, electric blues, and saturated oranges fall outside the CMYK gamut. When these colors are converted from RGB to CMYK, they shift -- typically becoming more muted.

Which Color Space to Use

Converting RGB to CMYK

Using ImageMagick:

# Basic RGB to CMYK conversion
magick input.jpg -colorspace CMYK output.tiff

# With a specific CMYK ICC profile (recommended)
magick input.jpg -profile sRGB.icc -profile USWebCoatedSWOP.icc output.tiff

# Convert and set DPI
magick input.jpg -profile sRGB.icc -profile USWebCoatedSWOP.icc \
  -density 300 -units PixelsPerInch output.tiff

Using Python (Pillow):

from PIL import Image

def rgb_to_cmyk(input_path, output_path):
    with Image.open(input_path) as img:
        if img.mode == "RGB":
            cmyk_img = img.convert("CMYK")
            cmyk_img.save(output_path, "TIFF", dpi=(300, 300))

File Format Selection for Print

Not all image formats are suitable for print. Here is what to use:

TIFF (Recommended for Professional Print)

TIFF is the gold standard for print because it supports CMYK color space, 16-bit color depth, lossless compression, and embedded ICC profiles. Nearly every professional print shop accepts TIFF.

# Convert to print-ready TIFF
magick input.jpg -colorspace CMYK -depth 16 \
  -compress LZW -density 300 output.tiff

PDF (Required for Some Workflows)

PDF/X is the ISO standard for print-ready files. It embeds fonts, images, and color profiles in a single, predictable package.

PNG (Acceptable for Some Print Services)

PNG works for consumer print services and photo printing. It supports lossless quality and high color depth but does not support CMYK.

JPG (Use With Caution)

JPG is acceptable for photo prints at quality 95+, but its lossy compression can introduce artifacts that become visible in large prints. If using JPG, set quality to 95 or higher.

For a comprehensive comparison of print formats, see our best file formats for printing guide.

Step-by-Step: Preparing an Image for Print

Step 1: Check Source Resolution

# Check image dimensions and DPI
magick identify -verbose input.jpg | grep -E "Geometry|Resolution|Units"

If the image does not have enough pixels for your target print size at 300 DPI, you need to either reduce the print size or upscale the image. Use the resize image tool to adjust dimensions.

Step 2: Set the Correct DPI

Setting DPI does not change the pixel count -- it changes how many pixels map to each inch of print:

# Set DPI without resampling (changes print size, not pixel count)
magick input.jpg -density 300 -units PixelsPerInch output.tiff

Step 3: Convert Color Space (If Required)

# For professional printing (CMYK)
magick input.jpg -profile sRGB.icc -profile USWebCoatedSWOP.icc output.tiff

# For photo printing (ensure sRGB)
magick input.jpg -profile sRGB.icc output.jpg

Step 4: Add Bleed (If Required)

Bleed is extra image area beyond the trim line that prevents white edges. Standard bleed is 0.125 inches (3mm) on each side:

# Add 0.125" bleed to each side (37.5 pixels at 300 DPI)
magick input.tiff -bordercolor white -border 38x38 output_with_bleed.tiff

Step 5: Convert to Final Format

# Final output as TIFF
magick input.tiff -compress LZW output_final.tiff

# Final output as high-quality JPG
magick input.tiff -quality 95 -sampling-factor 4:4:4 output_final.jpg

# Final output as PDF
magick input.tiff output_final.pdf

Common Print Specifications

Here are typical specifications for common print products:

Business Card

# 3.5" x 2" + 0.125" bleed = 3.75" x 2.25"
# At 300 DPI: 1125 x 675 pixels
magick source.jpg -resize 1125x675^ -gravity center \
  -extent 1125x675 -colorspace CMYK -density 300 business_card.tiff

Letter-Size Flyer (8.5" x 11")

# 8.5" x 11" + 0.125" bleed = 8.75" x 11.25"
# At 300 DPI: 2625 x 3375 pixels
magick source.jpg -resize 2625x3375^ -gravity center \
  -extent 2625x3375 -colorspace CMYK -density 300 flyer.tiff

Poster (24" x 36")

# 24" x 36" at 150 DPI (acceptable for posters)
# 3600 x 5400 pixels
magick source.jpg -resize 3600x5400^ -gravity center \
  -extent 3600x5400 -density 150 poster.tiff

Converting RAW Photos for Print

If you are working with RAW camera files (CR2, NEF, ARW, DNG), convert them to TIFF for maximum print quality rather than JPG:

# Convert RAW to 16-bit TIFF for print
dcraw -T -6 -w photo.cr2
# Result: photo.tiff (16-bit, camera white balance)

For batch RAW processing, see our how to convert RAW photos guide and the batch RAW to JPG workflow guide.

ICC Color Profiles

ICC (International Color Consortium) profiles define how colors should be interpreted. Using the correct profile ensures consistent color between your screen and the printed output.

Common ICC Profiles for Print

• USWebCoatedSWOP v2 -- Standard for web offset printing in North America
• ISOcoated_v2 -- Standard for offset printing in Europe
• JapanColor2001Coated -- Standard for offset printing in Japan
• GRACoL2006_Coated1v2 -- General requirements for commercial printing

Embedding an ICC Profile

# Embed sRGB profile (for photo prints)
magick input.jpg -profile sRGB.icc output.jpg

# Embed CMYK profile (for offset printing)
magick input.jpg -profile sRGB.icc -profile USWebCoatedSWOP.icc output.tiff

Ask your print service which ICC profile they prefer. Using the wrong profile can cause color shifts even when the conversion is technically correct.

Batch Converting Images for Print

When preparing multiple images for a print project:

#!/bin/bash
# Batch convert images for professional printing
INPUT_DIR="./web_images"
OUTPUT_DIR="./print_ready"
DPI=300
QUALITY=95

mkdir -p "$OUTPUT_DIR"

for img in "$INPUT_DIR"/*.{jpg,png,tiff}; do
  [ -f "$img" ] || continue
  filename=$(basename "$img" | sed 's/\.[^.]*$//')
  magick "$img" \
    -colorspace CMYK \
    -density $DPI -units PixelsPerInch \
    -compress LZW \
    "$OUTPUT_DIR/${filename}_print.tiff"
  echo "Prepared: $filename"
done

For more on batch processing workflows, see our batch processing guide.

Pre-Flight Checklist

Before sending files to print, verify:

1. Resolution -- At least 300 DPI at the final print size
2. Color space -- CMYK for offset printing, sRGB for photo/consumer services
3. ICC profile -- Embedded and matching the printer's requirements
4. Bleed -- 0.125 inches (3mm) on all sides for full-bleed prints
5. File format -- TIFF (preferred) or high-quality PDF/JPG
6. Color mode -- No spot colors unless specifically requested
7. Flattened layers -- All layers merged in the final file
8. Fonts -- Outlined/rasterized (for PDF submissions)

Use our image converter for quick format conversions and the image compressor only for web delivery -- never compress images destined for print.

Summary

Preparing images for print requires attention to three fundamentals: sufficient resolution (300 DPI for hand-held items, 150 DPI for distance viewing), correct color space (CMYK for professional offset, sRGB for consumer services), and an appropriate file format (TIFF for professional, high-quality JPG or PNG for consumer). Use our JPG converter, PNG converter, or TIFF converter to handle format changes, and consult our best file formats for printing guide for detailed format recommendations. When in doubt about specifications, always ask your print service for their requirements before converting.