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Position:Home>Visual Arts> Why can you scale pics/images down but not up?Question: Why can you scale pics/images down but not up!? If you take a pic on the internet and make it small, say, half the size, it's still perfectly clear!. But if you make it any bigger, it's blurry!. I don't see how it can stay perfectly clear at a smaller size, because you have less room to work with, so the colors would get blotched!.Www@QuestionHome@Com
Best Answer - Chosen by Asker: Take a simple example, suppose you have a file which is 144 pixels high by 144 pixels wide @ 72 ppi!. Your screen resolution is normally 72 pixels per inch (PPI) too so the picture would 2" X 2" on your screen!. By altering the files resolution we can adjust the size we want it to be on our screen!. We could bring the file into Photoshop or similar and make its resolution 36ppi, and we would get a picture 4" X 4" when 'plotted' on our screen, but the pixels would be bigger!. If we made the resolution of the file 18ppi the screen would plot that into an 8" X 8" picture, but the pixels would be like 'house bricks' and very blocky!. The reverse is true as well with the same file we could alter its resolution to 144ppi, it would only be 1" X 1" on our screen, but would appear more detailed because the pixels are finer!. The FILE resolution (PPI) tells the monitor how to plot the picture!. The higher the resolution the greater the detail, but the smaller the actual size, the lower the resolution the bigger the picture, but the quality is less!. In other words, you get the bigger size by having bigger pixels, to the point all you can see is pixels!. The only way to get a high quality large picture is to have a lot of information in the file to start with!. Suppose this time we have a picture file which is 3000 pixels by 3000 pixels!. At 72 PPI it would produce a picture which is 41!.666" X 41!.666" too big for the screen!. So we increase the resolution to something like 300ppi your monitor would plot that at 10" X 10", but to do so the pixels would be tiny and we would see a very good quality picture, a high resolution picture, but the file size would be 10Mb!. ChrisWww@QuestionHome@Com Photos/pictures are all made up of tiny little dots called pixels!. When you get really close to a newspaper photo, you can probably see them, you certainly can see them when you zoom in very closely on a digital picture!. To make something smaller, the computer simply has to leave a few pixels out here and there, but if you are trying to enlarge it, it has to invent pixels from out of nowhere or stretch the existing ones!. When you don't HAVE the necessary information, you can't expect to see it!.Www@QuestionHome@Com When you stretch an image from its original size, the image will become pixelated!. Say to take a picture of a Diagnoal (south east)!. Say the image is a Diagonal of a straight line!. Once we zoom and make this image bigger, you'll slowly see that this line turns to blocky stairs!. Eventually, the line won't be straight and fine but will be a jagged and blocky line!. Your monitor works on pixels (at least most monitors anyways) and if you make a picture from its original size, you'll suffer from pixelation unless you edit the picture afterwards!. With smaller pictures, it's all in removing pixels that will not fit!. Eventually, if you shrink a picture, you'll suffer from distortion as pieces of the picture will literally be left out as there is no room to fit the pixels in the image!. I hopet this helps!Www@QuestionHome@Com |