Pixels, what can you do with it?

Pixels, what can you do with it?

E-mail, web or screen
If you want to share a photo via e-mail or present on a website or slideshow, you must think in pixels. The best quality for a picture on a screen to display as one pixel of the picture coincides with a pixel of the monitor (100% or 1 in 1). If you have a digital camera with 8 million pixels, it makes these pictures of 3264 by 2448 pixels. See you this 1 on 1 (browser) on a monitor with a screen resolution of 1280 by 1024 pixels (SXGA), it remains 85% of the picture out of view. Which shows that we have a camera with 1.4 million pixels are enough to e-mail, website or display images to present.

Photos from digital cameras with more megapixels should therefore be reduced by physically removing pixels. This can in most photo editing programs like Adobe Photoshop Elements and Paint Shop Pro. In the dialog where you can do this, you can specify different variables. Make sure the unit is in pixels and specify the values of the reduced size of between 800 to 600 in 1280 and 1024 (4:3 compact camera). With a 3:2 aspect ratio (SLR camera) is 780 to 520 to 1260 at 840. Of the (printing) resolution is nothing to pull.

Print
How many pixels you need for a good print depends on the desired size of the print and the number of pixels per inch (2.45 cm) needed for a visually sharp print. These pixels or dots per inch (dpi) print resolution called, and this is important. The print resolution is less (fewer pixels / ink droplets per inch needed), as the size increases (see table).
Print Size (cm / inch) Viewing Distance (cm) (dpi) resolution Pixel Format Megapixels
15x10 / 6x4 30 300 1800 x1200 2.16
30x20 / 12x8 60 225 2700 x1800 4.86
60x40 / 24x16 120 140 3360 x2240 7.53
120x80 / 48x32 240 80 38x2560 9.83
This has to do with the viewing distance to the picture. A print of 15 by 10 cm to 30 cm and it looks requires 300 pixels per inch. At a magnification of 30 by 20 cm viewing distance is 60 cm. Your eye sees less detail and with 225dpi the picture still looks sharp. In a print of 75 by 50 cm, the viewer at least 1.5 meters away, and can decrease the resolution to 110 dpi.

In the same dialog in which you reduce the photos for use on a screen, projector or LCD TV you can also specify print size and resolution.

* Example 1: If the 8 megapixel camera (3264 by 2448 pixels) and you want to print at 200 dpi, then the width of the print 3264 divided by 200, being 16.32 inches (41.45 x 2.45 = cm)
* Example 2: Would you make a print of 30 by 20 cm (approx. 12x8 inches) at 225 dpi, then you have about 2700 pixels (= 12 x 225) in the required width and 1800 (= 8 x 225) in the height. This is a picture of almost 5 Megapixel.