Document Setup and Resolution
Resolution is a decision you make once, at document creation. Make it with the output in mind, not the screen.
Why this matters
A Photoshop document has a fixed pixel count set at creation. You can always resample to add pixels later, but resampling invents detail the image never had — it is a quality compromise, not a quality recovery. Starting at the right resolution for your intended output means the image was always as good as it needed to be. Starting too low means you are managing a ceiling that was self-imposed.
The resolution decision
Resolution is a relationship between pixel count, physical size, and output quality. These three variables are linked: fix any two and the third is determined.
| Variable | How it works | Your decision |
|---|---|---|
| Pixel count | Total pixels in width × height — the raw data in the file | Determined by your resolution and physical size choices at setup |
| Physical size | The intended output dimensions in inches or centimeters | You know this from the assignment context |
| PPI (resolution) | Pixels per inch — quality of the printed or displayed output | 150 PPI is the standard for this course |
At 150 PPI, a 2K output image (2048 pixels wide) represents approximately 13.6 inches wide at full quality. That is appropriate for a digital pin-up viewed at normal distance, projected presentation, and large-format inkjet output at pin-up distances. Use 300 PPI only when specifically asked — it quadruples the pixel count for the same physical size and produces file sizes that slow every operation without adding visible quality at typical viewing distances.
New document settings
| Setting | Value | Notes |
|---|---|---|
| Width × Height | 2048 px × 1080 px (2K) or match Lumion output dimensions | For Assignment 04 deliverables — match Lumion output resolution for consistency across all five images |
| Resolution | 150 PPI | Standard for this course. 300 PPI only when specifically requested. |
| Color mode | RGB Color, 8 Bits/Channel | RGB for digital output. 8-bit is appropriate for all LA117 deliverables. |
| Background contents | Transparent | Gives you maximum flexibility — a white background is a pixel layer you may not want |
| Color profile | sRGB IEC61966-2.1 | Embed the profile for consistent color across applications and screens |
Sizing for Lumion output consistency
Assignment 04 requires both original Photoshop images and three edited Lumion outputs — all at 2K resolution. For the edited Lumion images, the document size is determined by the Lumion export. Open the Lumion PNG/JPG directly and work on it. Do not resize it. For the original photo-collage and section/elevation images, match the pixel dimensions of the Lumion exports exactly so all five deliverables are the same size and can be placed consistently in InDesign.
Image size vs. canvas size
| Command | What it does |
|---|---|
| Image → Image Size | Resizes the entire image content — changing this resamples pixels if "Resample" is checked. Uncheck "Resample" to change PPI without changing pixel count (or physical size without changing quality). |
| Image → Canvas Size | Adds or removes space around the existing image without resampling the content. Use to extend the working area or crop to a precise output boundary. |
Try this
Create a new document at 2048 × 1080 px, 150 PPI. Note the pixel count. Then go to Image → Image Size, uncheck Resample, and change the resolution to 300 PPI. Note that the physical size halved while the pixel count stayed identical. Now re-check Resample and change the resolution back to 150 PPI — observe that Photoshop is now inventing pixels that didn't exist. This sequence makes the resolution relationship concrete before you're managing it under deadline pressure.
What breaks
Creating a document at screen dimensions without setting PPI — Photoshop defaults to 72 PPI in some workflows. A document that looks fine on screen at 72 PPI prints at 72 PPI, which is visibly pixelated at any print size. Always confirm PPI at document creation.
Resampling up to fix a low-resolution image — Photoshop's AI upscaling (Preserve Details 2.0) is impressive but does not recover actual detail. If a source image was captured or exported at insufficient resolution, upsampling makes it bigger, not better. Source imagery at higher resolution from the start.