When I zoom in using the Windows 7 Photo Viewer, why do I start seeing pixels?

Question

The Photo Viewer integrated in Windows 7 is showing pixels when I zoom in pictures:

I remember in Windows XP there weren't any pixels - everything was smooth.

As an example, I made a screenshot of a web page with a Firefox plugin and a screenshot of an Excel document with Evernote. Both are .PNG formats.

Here is the video

I have filmed myself using magnifier which you can see here

Note: set video playback to 720p HD in the lower right corner of the YouTube interface before playing the video.

How can I fix this?

P.S. I have 14" Matte screen laptop. Does it have something to do with this?

Answer 1

This is simple, but a guess, unless you can tell me otherwise.

a .PNG file is capable to storing vector based graphics, but in most situations, when/if you are taking a screenshot or similar, it is stored as raster graphics / bitmap.

So, if you are zooming in to a (bitmap/raster based) picture, typically, the system will attempt to automatically "antialias the image by filling in the gaps with other colours that make the image look more pleasant and easy on the eye.

(Left Default bitmap image zoomed in, right bitmap image with Anti Aliasing on).

Now, we get in to Vector Graphics - A vector graphic doesn't actually store the picture as pixels, it instead stores the picture as vectors or points. For example, if trying to describe a square, it would say, a line exists between A and B, B and C, C and D, D and A. The system then will draw (Render? Not sure on the term), that image at ANY zoom level, and it will look perfect.

In the same sort of way, True Type Fonts are Vectors:

This means that in any application such as word, you can zoom in or choose a font of size 500, and the font will look perfect. However, if you took a picture of the same instance of Microsoft Word and tried to zoom in, it will be a bitmap image that is saved and it will not look pleasant zoomed in past 100%.

AFAIK, it is not possible to take a vector screenshot.

To sum everything up, here is one last picture from Wikipedia. There is a high quality vector image of a bottle. When you export a section as bitmap, and the same as vector, then zoom in, here are the results:

And finally, if we are talking about the exact same image on both of your machines, but it just looks bad on your new one, if you have not enabled Clear Type (which should be on by default), it could be that your newer screen has a lower DPI, making images more "blocky"/pixelated.

You can test this by a simple formulae - (Screen Resolution * Screen Resultion) / inches (Providing your new screen is at the same aspect ratio). The higher the better.

Answer 2

What is going on is a programmatic choice difference between Windows XP and 7. In Windows XP, the photo viewer, when zooming the image past 100% scaling, would use an algorithm to smooth out hard edges. This is antialiasing. Because the image does not contain unlimited information since it doesn't have an unlimited resolution, if it is not smoothed after being zoomed, it will look blocky, like in Windows 7. Pixels, the individual dots making up an image, are rectangular, so when you zoom in on an image past 100%, you are basically taking a small rectangular point and blowing it up to a larger rectangular point. Windows XP performed a post process on zoomed in images to smooth out this blockiness.

If you want an image viewer that does this kind of post process when zooming in, I find that Google Picasa works well. However, don't expect to gain any new detail this way. It cannot create detail where there isn't any (despite what TV crime dramas may try to suggest). You can't change the behavior of the Windows Photo Viewer. So, installing a 3rd party option is really your best bet.

And no, the type of screen that you have installed has nothing to do with it. This is purely a software-side thing.

Answer 3

I believe these "pixels" you are talking about are due to anti-aliasing. Displays are incapable of creating straight lines at an angle, as well as curves. Windows, as well as other programs use anti aliasing techniques to trick the eye into thinking the image is better than it is. These pixels are virtually invisible at the proper resolution, however when the screen is captured and zoomed, they stick out.

Look at this wikipedia article on anti-aliasing to learn more.

Answer 4

Your recollection of WinXp versus Win7 is correct.

I've recently noticed this difference between the photo viewers of Windows XP and Windows 7 also. The Win 7 viewer simply does a quick and dirty scaling (throw away pixels or just replicate pixels) of the image if you're viewing at anything other than 1:1 pixel mapping. The XP photo & fax viewer does a much better job of scaling. Diagonal lines/edges in the XP viewer will be smoothed out when downscaling or upscaling, whereas the same image in 7 will be a staircase or jaggies. Really a step backwards by Microsoft! I suspect there is nothing to do but find another photo viewer for Win7.

BTW all viewing was on a CRT computer monitor (dual-boot system), so your LCD display is not a factor.

Answer 5

Not everything scales up correctly when zooming, since pixels cannot appear from nowhere.

The zooming of a picture entails very simply the "widening" of the pixels, so that each pixel is displayed as more than one pixel. The result is that the picture becomes "blocky", where each original pixel is shown as a block of several pixels. The quality of the zoom depends on the ability of the zoom software to "invent" pixels where there are none, so as to avoid too many artifacts.

I do not believe in the degradation of the quality of the zoom in Photo Viewer, but I believe that you have fallen into another trap of Windows 7 : The text is "sprinkled" with pixels intended to give it a beautiful 3D look. However, this beautiful text does not scale up : When zomming one sees all the scattered pixels.

To take screenshots, the solution is to change your tool. Use instead the Windows 7 Sniping Tool, which does not capture these extra pixels. The results then scale up much better.