After rumors surfaced yesterday of a 13” MacBook Pro with retina display, I couldn’t help but wonder what the resolution would be. Instead of breaking it down by resolution, I decided to separate each theory by pixel density.
The current 13” MacBook Pro has a resolution of 1280 x 800. When Apple introduced the 15” retina they doubled the resolution of the 15” MacBook Pro (1440 x 900). Doubling the current resolution of the 13” MB Pro would yield a resolution of 2560 x 1600. This creates a density of 227 ppi. The problem is that Apple makes no displays with this pixel density. It sits right between the 220 ppi of the 15” retina and the 264 ppi of the iPad. Apple would have to create or use an entire new manufacturing line for this display. This is expensive, but when you have over $100 billion in the bank, anything is possible. To me, this seems like the most likely option.
Another possibility for Apple is to cut a 13” panel from the same 220 dpi display sheets as the 15” MB Pro retina. If this were to happen, the display would have a resolution of 2457.5784 x 1554.7365. You cannot have fractional pixels, so this obviously isn’t the exact resolution. However, Apple could make the screen a tiny bit bigger or smaller than 13.3” to allow the use of this panel. For example, if the display size was increased to 13.689” a 2560 x 1600 screen would have the same the same 220.53 dpi as the 15” retina. These numbers probably aren’t exactly right, but you get the idea. I’m an economist, not a display engineer.
Using the same 2880 x 1800 resolution found on the 15” retina laptop seems unlikely to me, but it is definitely a possibility. Given that the 13” MacBook Air comes with a 1440 x 900 screen, we know that a doubled display (2880 x 1800) should work fine. Display elements wouldn’t be too small. The density would be 255 ppi. Again, the problem is that Apple does not make any displays with this pixel density. This is the least likely option.