Units

For print documents, the concept of PPI refers to pixels per inch, or how many pixels you have in each physical pixel.

Screen resolutions

For print documents, the concept of PPI refers to pixels per inch, or how many pixels you have in each physical pixel.

Aspect Ratios

Up until the iPhone X, pretty much all phones had a 16:9 aspect ratio. Android phones usually had 720x1280 (HD) or 1080x1920 (Full HD) displays, and the iPhone 6/7/8 had a 750x1334 display.

Things are now a bit more complicated - Android phones can be 18:9 or even 21:9, meaning that there’s no single frame size that accurately depicts most phones.

Resizing frames without scaling content

Hold down Command (on Mac) or Control (on Windows) to resize a frame and ignore scaling or constraints set for any child elements.

How do you manage this then?

Designers that have studied and internalised grid systems may find it a little hard to adjust to digital systems where the canvas is always changing, and the size of elements is always changing as well. My approach is to just give in to the chaos—it’s not possible to control everything with the level of granularity you can have when designing a print document or a PDF.