{"id":16,"date":"2015-12-23T16:39:00","date_gmt":"2015-12-23T16:39:00","guid":{"rendered":"http:\/\/www.revolutionsincommunication.com\/viscomm\/?page_id=16"},"modified":"2026-01-07T18:33:07","modified_gmt":"2026-01-07T18:33:07","slug":"pixels","status":"publish","type":"page","link":"https:\/\/revolutionsincommunication.com\/viscomm\/pixels\/","title":{"rendered":""},"content":{"rendered":"

Pixels and Imaging Resolution<\/strong><\/span><\/h3>\n

What’s a pixel?\u00a0<\/strong><\/span><\/h4>\n

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A pixel is a “picture element,” and it’s the basic unit in digital photography.\u00a0 When you edit a photo and zoom in on a digital image, you’ll get down to the individual pixel fairly quickly.\u00a0 Pixels are the basic reference for technical issues. For instance, image resolution is measured in terms of “pixels per inch” (or centimeter) and also in terms of bits per pixel.\u00a0 \u00a0<\/span><\/p>\n

Screen resolution:\u00a0\u00a0<\/em><\/strong><\/span><\/h4>\n

Most computer monitors have a standard screen resolution of 72 pixels per inch (which corresponds with the ancient typesetting system of 72 points per inch). This is changing with high definition screens, but is still a general rule. You usually don\u2019t want or need more than 72 ppi for a photo that will be displayed on the web.\u00a0<\/span><\/p>\n

All of the pixels together make up a picture that can be very large, with lots of detail, or very small, with most of the detail taken out.<\/span><\/p>\n

File size\u00a0<\/b><\/span><\/h4>\n

File size is measured in Kilobytes (thousands of bytes) and Megabytes (millions of bytes). So 1,000 kilobytes (Kb) is the same as one megabyte (1Mb).<\/p>\n

For printed images, we want larger<\/em> file<\/strong> sizes because printed images require higher resolutions. Anywhere from 6 to 30 Mb or more is best for printed images.<\/p>\n

For the web, we want smaller<\/em> file sizes<\/strong> so that users dont have to wait for them to load in a browser. It’s best to uses images of 100 to 500 Kb.A related issue is that you don\u2019t want large files that take too long to download. \u00a0For web, you want to change from (say) 300 pixels per inch (ppi)\u00a0\u00a0to 72 ppi.<\/p>\n

Bit depth \/ Pixel resolution <\/b><\/span><\/h4>\n
Every pixel is made up of bits of information. The more bits a pixel has, the broader a tonal range and the better the image resolution.<\/div>\n
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One bit: a “bitmap” image<\/strong> uses a bit depth of only one bit per pixel. Since a bit is either on or off (1 or 0), it creates a crude black and white image with no depth. These were some of the earliest experimental digital images.<\/div>\n
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Eight bit processing:\u00a0 <\/b>That is what the Nintendo Mario Brothers game system used when it was introduced in 1983. Because it only had 256 possible colors, the early game systems had a cartoonish color scheme.\u00a0 These systems compensated for their limitations\u00a0 by “indexing” colors, which allowed separate color pallets.<\/div>\n
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So you could have 256 pixels that were mostly blue and white, if Mario was stuck in an arctic scene, or you could have a pallet that was mostly red and yellow for a desert scene.\u00a0 The “indexed”\u00a0 mode, 8 bit color format is usually a .gif (graphic image format) also called a Compuserv Gif.<\/div>\n
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Sixteen bit processing\u00a0 <\/b>was an intermediate step in the game industry. It was actually two 8 bit processors working in tandem, but it made a difference in game play and resolution.\u00a0 This 16-bit Super NES game Zelda, introduced in 1991,\u00a0 had 65,000 possible colors, and that made it much easier on the eyes than the old 8-bit game.<\/div>\n
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Thirty two bit processing<\/strong>\u00a0 and more sophisticated 64 bit processing has been used for regular photos since 1993.\u00a0 Computer processors could handle 32 bits of addressing in image files, which, in three channels, allowed for 16.8 million possible colors. This was more than enough for any photo or image, and the three channels in the “RGB” mode could be exchanged as\u00a0 jpg, tiff or other formats.\u00a0 \u00a0It was also possible to have four channels for “CMYK” mode printing (esp. tiff format) and png for the web where the fourth channel could be an alpha control.<\/div>\n
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To see how image quality is related to pixel depth,<\/strong> we can open a large (10 mb or more) file in Photoshop.\u00a0 Then pull down to File \/ Export \/ Save for Web (Legacy).\u00a0 You’ll get a dialogue box that lets you specify different numbers of colors in your image. For example, instead of 16 million colors in the image on the right, the image on the left has 16\u00a0 colors.<\/p>\n\n\n\n
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Eight bit GIF format photo with 256 possible colors<\/p><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

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PIXEL DEPTH AND COLOR<\/b><\/p>\n

\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
Bits per pixel<\/b><\/td>\nColors<\/b><\/td>\nExplanation<\/b><\/td>\nMode<\/td>\nFormat<\/td>\n<\/tr>\n
1<\/td>\n2<\/td>\nTwo possible \u2014 black or white<\/td>\nBitmap<\/td>\n.bmp<\/strong><\/td>\n<\/tr>\n
2<\/td>\n4<\/td>\nFour possible 2 x 2<\/td>\nGreyscale, Indexed<\/td>\n.gif<\/strong><\/td>\n<\/tr>\n
3<\/td>\n8<\/td>\nEight possible colors 2 x 2 x 2<\/td>\nGreyscale, Indexed<\/td>\n.gif<\/strong><\/td>\n<\/tr>\n
4<\/td>\n16<\/td>\n2 x 2 x 2 x 2<\/td>\nGreyscale, Indexed<\/td>\n.gif<\/strong><\/td>\n<\/tr>\n
5<\/td>\n32<\/td>\n2 x 2 x 2 x 2 x 2<\/td>\nGreyscale, Indexed<\/td>\n.gif<\/strong><\/td>\n<\/tr>\n
6<\/td>\n64<\/td>\n2 x 2 x 2 x 2 x 2 x 2<\/td>\nGreyscale, Indexed<\/td>\n.gif<\/strong><\/td>\n<\/tr>\n
7<\/td>\n128<\/td>\n2 x 2 x 2 x 2 x 2 x 2 x 2<\/td>\nGreyscale, Indexed<\/td>\n.gif<\/strong><\/td>\n<\/tr>\n
8<\/td>\n256<\/td>\n2 x 2 x 2 x 2 x 2 x 2 x 2 x 2<\/td>\nGreyscale, Indexed<\/td>\n.gif<\/strong><\/td>\n<\/tr>\n
16<\/td>\n65,536<\/td>\nTwo channels of 8 bits = 256 x 256<\/td>\ngame systems (Super NES)<\/td>\n.gif<\/strong><\/td>\n<\/tr>\n
24<\/td>\n16.8 million<\/td>\nThree channels of 8 bits each = 256 x 256 x 256<\/td>\nRGB (red, green, blue) for projected media<\/td>\n.jpg<\/strong><\/td>\n<\/tr>\n
32<\/td>\n4 billion<\/td>\nFour channels of 8 bits each = 256 x 256 x 256 x 256<\/td>\nRGB plus Alpha channel<\/td>\n.png<\/strong><\/p>\n

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32<\/td>\n4 billion<\/td>\nFour channels of 8 bits each = 256 x 256 x 256 x 256<\/td>\nCMYK (cyan, magenta, yellow, black) for printed media<\/td>\n.tiff<\/strong><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n

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Pixels and Imaging Resolution What’s a pixel?\u00a0 A pixel is a “picture element,” and it’s the basic unit in digital photography.\u00a0 When you edit a photo and zoom in on a digital image, you’ll get down to the individual pixel … Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":3,"comment_status":"closed","ping_status":"closed","template":"full-width-page.php","meta":{"nf_dc_page":"","footnotes":""},"class_list":["post-16","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/revolutionsincommunication.com\/viscomm\/wp-json\/wp\/v2\/pages\/16","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/revolutionsincommunication.com\/viscomm\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/revolutionsincommunication.com\/viscomm\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/revolutionsincommunication.com\/viscomm\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/revolutionsincommunication.com\/viscomm\/wp-json\/wp\/v2\/comments?post=16"}],"version-history":[{"count":5,"href":"https:\/\/revolutionsincommunication.com\/viscomm\/wp-json\/wp\/v2\/pages\/16\/revisions"}],"predecessor-version":[{"id":3392,"href":"https:\/\/revolutionsincommunication.com\/viscomm\/wp-json\/wp\/v2\/pages\/16\/revisions\/3392"}],"wp:attachment":[{"href":"https:\/\/revolutionsincommunication.com\/viscomm\/wp-json\/wp\/v2\/media?parent=16"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}