Episode 92
The Pixels 101 Show
June 9, 2017 · Mike Murphy
EP92: THE PIXELS 101 SHOW Today is all about pixels and resolutions and understanding the fundamentals of sizing and preparing photos and videos for use on the web.. Episode Summary: What are pixels? What is resolution and ppi? What does 720p, 1080p and 4K mean? What is aspect ratio?
Episode Summary: A fundamentals episode on pixels, resolution, and aspect ratio — the building blocks for correctly sizing and preparing photos and videos for the web.
What You’ll Learn
- What pixels actually are, and why smaller/tighter pixels mean higher quality
- The difference between resolution/PPI for photos and resolution terms for video
- What 720p, 1080p, and 4K actually mean in pixel dimensions
- What aspect ratio is and the most common ratios used in online video
Understanding how photos and videos get prepared for online content makes it a lot easier to focus on the actual creating.
Pixels
Digital photos and videos are made up of individual pixel units. When an image looks clean and sharp, the pixels are invisible; when it looks blurry or blocky, it’s “pixelated” — the pixels themselves are visible. The “p” in 1080p and the “px” in 1920px × 1080px both refer to pixels. Smaller, more tightly packed pixels mean higher quality — and a larger file size. Tip: it’s always better to size an image down than to try enlarging a small one.
Resolution and PPI
“High-res” and “low-res” describe resolution — the density of pixels packed into an image. Those terms don’t apply to video; video uses standard-def, high-def, or 4K instead.
- High res usually means print-ready, sized at real print dimensions — e.g., 5×7 inches at 300 PPI (pixels per inch).
- Low res is best for web and screens, typically 72–96 PPI. With Retina and 4K+ displays, some now recommend going as high as 150 PPI.
- PPI = pixels per inch. DPI = dots per inch (a printing term).
Pro tip: export at the lowest file size that still looks good, and nudge quality up only when it visibly degrades. Big, high-res images may look great, but they slow page load and frustrate visitors — trial and error settles the right balance over time. For web images in Adobe Lightroom, setting the “Long Edge” to 2048px at quality 80 is a solid starting point.
Relation to podcasting: episodes don’t get exported at maximum quality either — the file size would balloon and take longer to download and more space on a phone, so the same balance applies to audio.
Video: Aspect Ratio
Aspect ratio is simply the relationship between a video or photo’s width and height — proportions, not size. The most common online video ratio is 16:9 (width:height) — the standard for horizontal YouTube video and most iPhone recordings, often called 1080p or HD.
The one number worth memorizing: 1920×1080 pixels at a 16:9 aspect ratio covers roughly 90% of video production needs. Video thumbnails follow the same 1920×1080 template at 72 DPI.
- HD video (most common): 1080p — 1920×1080px, 16:9
- Standard HD (older): 720p — 1280×720px, 16:9
- Vertical video: 1080×1920px, 9:16
- Square video: 1920×1920px, 1:1
Aspect ratio calculators are genuinely handy for working out unfamiliar dimensions.