Raster or vector for this job?

What raster actually is (pixel grid, resolution-bound)

Raster files are made of pixels arranged in a grid. Each pixel has a specific color. The total number of pixels determines the file's resolution. Raster images are resolution-bound, meaning they look good only at their native size or smaller. Think of it like a mosaic – each small tile (pixel) has a specific color, and when you look at the whole picture from a distance, it appears smooth. But when you get too close, you see the individual tiles.

When you enlarge a raster image, the pixels become visible, resulting in pixelation or blurriness. This is why photos from websites (typically 72 PPI) look poor when enlarged for print. A 200×200 pixel logo from a website, when enlarged to 10×10 inches, becomes only 20 PPI – visibly pixelated and unprofessional. Raster files are best suited for photographs and complex images where subtle color transitions and gradients are important.

What vector actually is (paths, resolution-independent)

Vector files use mathematical paths and shapes to define graphics. Instead of pixels, they store points, lines, and curves. This makes them resolution-independent, meaning they stay crisp at any size. Vector graphics are defined by equations rather than pixels, so they can be scaled infinitely without losing quality.

Vector graphics are ideal for logos, illustrations, and text because they can be scaled infinitely without losing quality. They are smaller in file size for simple graphics and can be edited easily. A vector logo created today can be used on a business card or a billboard without any loss of quality, making them perfect for brands that need consistency across different media sizes.

The zoom test: how to tell raster from vector

Zoom way in on a file. If the edges become pixelated and you can see individual squares, it's raster. If the edges remain smooth and crisp no matter how far you zoom, it's vector. This test works because vector files store instructions for drawing, while raster files store the final pixels.

The zoom test is the quickest way to identify file types in practice. In Adobe Illustrator, you can zoom to 6400% and vector artwork remains perfectly crisp, while raster images show individual pixels. This difference is crucial for print work where files may be scaled significantly during production.

Worked example: Effective PPI of a placed raster logo scaled in a layout

Let's calculate the effective PPI of a logo placed in a layout. Suppose you have a 1000×1000 pixel logo at 72 PPI, and you place it in a design at 5×5 inches. The effective PPI becomes 1000÷5 = 200 PPI. Now, if your final print size is 10×10 inches, the effective PPI drops to 1000÷10 = 100 PPI – too low for quality print. To maintain 300 PPI at 10×10 inches, you'd need a 3000×3000 pixel image (3000÷10 = 300 PPI).

This arithmetic shows why source image resolution matters. Always calculate the effective PPI by dividing pixel dimensions by print dimensions. For a business card (3.5×2 inches), a 1050×600 pixel image gives 300 PPI (1050÷3.5 = 300). For a banner (36×24 inches), you'd need 10800×7200 pixels at 300 PPI – a massive file that may require optimization or vector alternatives.

Where each wins: photos vs logos/type

Raster files excel for photographs and complex images with subtle color transitions. Vector files excel for logos, icons, and text where crisp edges and scalability are important. Raster is necessary for continuous tone images like photographs, while vector is ideal for flat color graphics and typography.

Use raster for: photographs, scanned documents, complex illustrations with many colors, gradients, and textures. Use vector for: logos, icons, text, simple illustrations, graphics that need to be resized, and any element where crisp edges at any size are critical. Many professional designs use a combination: vector logos and text with raster photographs.

Why vector text stays crisp in PDFs (and what happens when rasterized)

Vector text is stored as paths, not pixels. This means it can be scaled to any size and remain perfectly crisp. When text is rasterized (converted to pixels), it loses this advantage and becomes resolution-dependent. Rasterized text is essentially a photograph of the text, so it inherits all the limitations of raster images.

Rasterized text may appear blurry or have jagged edges, especially at small sizes or low resolutions. Always keep text as vector when possible for print work. In Adobe InDesign, text remains vector until you export to PDF with text outlined. Even then, high-quality PDFs preserve text as vector by default unless specifically instructed otherwise.

The classic failure: logo pulled from a website at 200 px reused on a banner

A common mistake is taking a small raster logo from a website (typically 72 PPI) and using it in large print materials. The result is a pixelated, unprofessional appearance. For example, a 200×200 pixel web logo enlarged to 24×24 inches becomes only 8.3 PPI – visibly pixelated and unsuitable for print.

Always obtain vector versions of logos when available. If only raster is available, use the highest resolution version and check that it meets your print requirements (typically 300 PPI at final size). For the 24×24 inch banner, you'd need at least 7200×7200 pixels (300 PPI) – likely unavailable from web sources, highlighting the importance of source file quality.

Raster effects inside vector files: the hidden compromise

Many vector files contain raster elements like drop shadows, gradients, or complex textures. These raster effects become resolution-dependent even in a vector container. A vector logo with a raster drop shadow will look crisp until enlarged, when the shadow becomes pixelated while the logo remains sharp.

Be aware of raster effects in your vector files. They may look fine on screen but become pixelated when enlarged for print. Simplify or replace raster effects with vector alternatives when possible. In Adobe Illustrator, you can often convert raster effects to vector using the 'Expand' function, though results vary by complexity.

SVG, PDF, EPS, AI: Honest comparison of vector formats

SVG (Scalable Vector Graphics) is web-focused, using XML. It's great for web but less ideal for print due to potential rendering differences and lack of CMYK support in some viewers. SVG files can be edited in code editors and are resolution-independent.

PDF is the print industry standard, supporting both vector and raster content with precise color management. It preserves vector data and is widely accepted by printers. EPS (Encapsulated PostScript) is an older format still used in some workflows but less common today. AI (Adobe Illustrator) is a proprietary format that preserves all editing capabilities but requires Adobe software.

For print, PDF is generally the best choice as it's widely supported and preserves vector data. SVG can work but may require conversion. EPS is legacy; avoid unless specifically requested. AI is good for editing but should be exported to PDF for final delivery.

Fonts as the vector case people forget: Embedding vs outlining

Fonts are vector-based by nature, storing character shapes as mathematical paths. When you use a font in a design, the vector data is either embedded or outlined. Embedded fonts include the glyph information needed for output, so a separate installation of that font is normally unnecessary for faithful rendering. Editing may still require the original font and appropriate permissions. Outlined fonts convert text to vector paths, making it uneditable but ensuring consistent appearance.

Prefer embedded fonts, including valid subsets, for normal PDF delivery. Embedding prevents substitution; it is not a way to invite printer-side substitutions. Outline text only for a specific workflow requirement, and keep an editable original because outlines lose searchable text and other live-text benefits.

PDFs carrying both: how modern files work

PDF files can contain both vector and raster content. A typical print PDF might have vector text and logos with raster photographs. The PDF format handles this combination gracefully, preserving the best of both worlds.

When saving as PDF, ensure that vector elements remain vector and raster elements meet resolution requirements. Some PDF exports may inadvertently rasterize vector content, especially with complex effects. Use 'Preserve Illustrator Editing Capabilities' or similar options to maintain vector data. Always check the PDF export settings for 'Compression' and 'Resolution' to control raster elements.

What "outlining fonts" means and its tradeoffs

Outlining fonts converts text to vector paths, embedding the character shapes directly in the file. This ensures the text looks the same on any system but makes it uneditable. Outlined text becomes part of the graphic, not editable text.

The tradeoff is editability: outlined text cannot be changed. Use outlining only when necessary for final output. Keep an editable version for future changes. Outlining is common for final PDF delivery to printers, but designers should maintain the original editable file for revisions.

File plan walkthrough: Logo on business card vs banner

For a business card (3.5×2 inches), a vector logo is ideal. The small size means vector's scalability advantage is less critical, but crisp edges at any print resolution are essential. Pair with high-res raster photos at 300 PPI (1050×600 pixels). Export as PDF/X-1a with embedded fonts.

For a banner (36×24 inches), vector is mandatory. The large size would make any raster logo pixelated. Use vector artwork scaled appropriately. Raster photos need massive resolution (10800×7200 pixels at 300 PPI) or consider vector alternatives for simpler graphics. Export as high-quality PDF with raster images at required resolution and vector elements preserved.

Practical file plan for a print job

For professional print work, maintain a master vector file for logos and text. Place raster images at their effective print resolution (300 PPI). Export per printer specifications, keeping vector elements vector and ensuring raster meets requirements. Use version control to track changes.

This approach gives you the best of both worlds: scalable vector graphics and high-quality raster images, resulting in professional print output. Always keep source files and export settings documented for future projects or printer inquiries.