Two Tools, One Discipline
Raster Editing Fundamentals
Chapter 1 · Two Tools, One Discipline
This course teaches raster image editing as a discipline, using Photoshop and GIMP as two parallel, independently-built implementations of it. Before any of that, it's worth being precise about what "raster editing" actually means, and what this course deliberately isn't.
Raster vs. Vector: A Genuinely Different Kind of Image
A raster image is a fixed grid of individual pixels — resolution-dependent, meaning scaling it up beyond its original size degrades quality, since there's simply no more detail to reveal. A vector image instead stores mathematical paths and shapes, scaling to any size with no quality loss at all. This course covers raster editing specifically — vector tools like Illustrator and Inkscape belong to a genuinely different discipline, covered separately (Vector Graphics, still on this site's own bucket list) rather than being a different tool for the identical job.
Two Tools, One Discipline
Unlike the JetBrains family (Text Editors & IDEs Survey's own Chapter 4), Photoshop and GIMP share no underlying platform at all — they're separate, unrelated products built by entirely different teams. What they genuinely share is the underlying discipline: both operate on the same kind of image, a grid of pixels, and both solve the same categories of problem — selections, layers, masks, color correction — independently. This course teaches that discipline once per concept, then shows it concretely in both tools.
Proprietary vs. Free/Open-Source
Photoshop is Adobe's own commercial product, sold via a Creative Cloud subscription, and remains the industry standard across many professional contexts. GIMP is free and open-source, developed by a community rather than a single company. This is a real, practical difference worth knowing upfront — not a technical footnote to skim past.
How This Course Is Structured
Each concept chapter teaches one idea conceptually first, then shows it concretely in both tools with terminology mapped between them — Photoshop's own name for a feature alongside GIMP's own name for the equivalent concept. The capstone (Chapter 10) applies every concept from this course to one real photo, edited end to end, with both tools' own workflows shown side by side at each step.
| Aspect | Photoshop | GIMP |
|---|---|---|
| Cost model | Commercial, Creative Cloud subscription | Free, open-source |
| Development | Adobe (single company) | Community-developed |
| Native format | PSD | XCF |
| Industry standing | Widely considered the standard | A genuine, capable alternative |
Hands-On Exercises
A company logo needs to appear on a business card, a billboard, and a website favicon — three wildly different sizes. Using this chapter's own material, explain whether it should be created and stored as a raster or vector image, and why.
📄 View solutionExplain why Photoshop and GIMP are described in this chapter as sharing "a discipline" rather than sharing "a platform," and why that distinction matters for how this course is structured.
📄 View solutionA colleague says "GIMP is basically just free Photoshop, so there's nothing really to learn separately about it." Using this chapter's own warning box, explain what's wrong with this framing.
📄 View solutionChapter 1 Quick Reference
- Raster — a fixed pixel grid, resolution-dependent. Vector — mathematical paths, scales infinitely. This course covers raster only.
- Photoshop and GIMP share a discipline, not a platform — independently built, solving the same problems separately
- Photoshop — commercial, Creative Cloud subscription. GIMP — free, open-source, community-developed
- This course teaches each concept once, then shows it concretely in both tools, with terminology mapped between them
- GIMP is genuinely different software, not a feature-for-feature clone of Photoshop