Let me get this straight PPI is pixels per inch right? So if i reduce my PPI the image becomes more pixelated or what? How can i get more resolution if i have a LOW resolution and a High PPI? I don’t understand. I know that a higher PPI means a higher pixel density but doesn’t that equals more pixels?!? thereforE a larger X Y Resolution, i don’t get it
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If you look at this grid in the image, say the 3rd one [https://www.giffgaff.com/blog/pixel-density-how-to-calculate-ppi/pixel-density-explained.png](https://www.giffgaff.com/blog/pixel-density-how-to-calculate-ppi/pixel-density-explained.png) there is 4×4 pixels, but on the last grid there’s a higher PPI but it’s a 8×8 resolution? So doesn’t that mean a higher PPI has more pixels?
Resolution is the total number of pixels on the screen. PPI is the number of pixels in an inch.
For a fixed sized display, if one goes up so does the other, and vice versa.
But not all displays are the same size. If you increase the physical size of a display (say from 24″ to 27″) but keep the same resolution, then the PPI will go down: the same number of pixels is now spread over a larger screen.
That’s why your 1080p phone screen can look sharp from only 20 or so cm away, but if you looked at a 30″ 1080p TB from 20 cm distance, you’d easily be able to see individual pixels.
Yes, PPI is pixels per inch. It’s what connects the number of pixles (resolution) to the physical size of the image.
If I have a 10×10 image (very low resolution) and I print it at 10 ppi it’s 1″ x 1″. If I print it at 1ppi it’s 10″ x 10″.
If you reduce your PPI *and keep the image the same physical size* then individual pixels get physically bigger…more pixelated.
A low resolution image at high PPI looks better because the pixels are physically smaller…but so is the image.
Pixels are kind off like lightbulbs, resolution in this context usually refers to the total amount of lightbulbs per side of the screen, PPI refers to the amount of lightbulbs per square inch in the screen.
Does that clear it up somewhat?
PPI relates the pixel count to a size on paper, monitor screen or flatbed scanner. If you reduce the pixels per inch, the image gets enlarged and imperfections in it can more easily be seen. Or if you want to keep the physical dimensions the same, you have to resample and discard some pixels. Increasing PPI requires upsampling, which interpolates new pixel values but can’t create actual accurate data that was not initially captured.
PPI is pixels PER INCH so the total number of pixels still vary based on the screen. Let’s say you have 6 ppi. On a 1 inch screen this will be 6 pixels. On a 2 inch screen you’ll have 12. So increasing the screen size will increase the resolution and make the screen bigger.
I think one of the things your missing is that pixels aren’t all the same size, it depends on the resolution and size of the screen. If you have a 4k tv and a 4k phone, they will have the same number of pixels. But the pixels on the phone will be smaller, so it will have a mother ppi. so the tv will be more pixelated than the phone. BUT, your eyes might not be able to notice it. You’re meant to sit further away from a tv and your eyes probably won’t be able to tell the difference.
PPI (or DPI, synonymous) measures how many pixels you’re displaying in the physical distance of 1 inch. Reducing it *while not changing the resolution of the image* means taking the same number of pixels but printing them less densely –> blowing up the image, possibly to the point of making it visibly pixelated. You can’t get a higher resolution out of nowhere (not without photoshop/equivalent sharpener magic, anyway, and that has limitations).
If you have the same number of pixels but a larger value for PPI/DPI, the output image, ie print size or image pasted into a document, will be smaller. The DPI value doesnt change the resolution of the digital data itself.
For example a 1200 x 1200 pixel image with the DPI set to 600 will print out at 2″ x 2″ . The same image with no change to the pixels but the DPI now set to 300 will print out at 4″ x 4″ .
On the other hand, if you want a 4″ x 4″ image at 600 DPI print resolution you need a 2400 x 2400 pixel source image.
The word “resolution” has been used two completely different ways in contexts that are ever so slightly different but still very close to each other, which can add to confusion here.
When people talk about computer screens they usually take “resolution” to mean total pixels that exist horizontally and vertically on the screen.
But there’s an older analog meaning of the word that pre-dates that, and it’s still used in some digital world cases, and that’s to say that resolution is NOT the total pixels but rather it’s how close together two dots can be and still be detected as two dots and not merge into 1 dot. If you talk about the resolution of the human eye, for example, it’s not a total count of how many “pixels” (rods and cones) you have on the retina, but of how close together they are on the retina and how that affects your ability to “resolve” two dots as separate dots. (Thus the word “resolution” – how tightly can you resolve the difference between the two things.)
In the computer world, there are still some contexts where this meaning of “resolution” is used – not a total count of pixels but a measure of how far apart two adjacent pixels are (which PPI can tell you, in inverse). This is relevant to the people who manufacture computer screen technology. It lets them know, for example, “If I want a screen resolution of X pixels across, and my pixel resolution with this particular screen technology is Y pixels per inch, then the screen has to be at least X*Y inches across to be able to do that. If I want that screen resolution on a smaller screen, I have to go with a more expensive, tighter pixel resolution to do it.
It gets confusing because you might have meant either meaning in play, and sometimes it swaps between them mid-sentence like in the above sentence.
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