{"id":1968,"date":"2019-08-07T17:17:32","date_gmt":"2019-08-07T22:17:32","guid":{"rendered":"https:\/\/www.rayson.us\/aehanson\/?page_id=1968"},"modified":"2019-10-08T10:25:29","modified_gmt":"2019-10-08T15:25:29","slug":"digitalimages","status":"publish","type":"page","link":"https:\/\/www.rayson.us\/aehanson\/digitalimages\/","title":{"rendered":"Digital Images Demystified"},"content":{"rendered":"<p><a href=\"https:\/\/www.rayson.us\/aehanson\/wp-content\/uploads\/2019\/08\/diagram.png\"><img loading=\"lazy\" decoding=\"async\" class=\"alignleft wp-image-1971 size-medium\" src=\"https:\/\/www.rayson.us\/aehanson\/wp-content\/uploads\/2019\/08\/diagram-300x96.png\" alt=\"\" width=\"300\" height=\"96\" srcset=\"https:\/\/www.rayson.us\/aehanson\/wp-content\/uploads\/2019\/08\/diagram-300x96.png 300w, https:\/\/www.rayson.us\/aehanson\/wp-content\/uploads\/2019\/08\/diagram-768x247.png 768w, https:\/\/www.rayson.us\/aehanson\/wp-content\/uploads\/2019\/08\/diagram-1024x329.png 1024w, https:\/\/www.rayson.us\/aehanson\/wp-content\/uploads\/2019\/08\/diagram.png 1834w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><\/p>\n<p><em>Most of us don\u2019t know how a JPEG file differs from a TIFF file and whether or not that difference is important. This presentation will provide you with a basic understanding of how images are digitized and will familiarize you with some of the fundamental characteristics of digital image files.<\/em><\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<h1>Tony Hanson<\/h1>\n<p>I have several PDF-formatted files available for this presentation:<\/p>\n<ul>\n<li>An <a href=\"https:\/\/www.rayson.us\/Presentations\/digitalimages\/Hanson-Demystifying-Digital_Images.pdf\" target=\"_blank\" rel=\"noopener noreferrer\">outline of my presentation<\/a> (which is just the information on this page reformatted and saved in a PDF file)<\/li>\n<li>Copies of the slides in my presentation (<a href=\"https:\/\/www.rayson.us\/Presentations\/digitalimages\/Hanson-Demystifying-Digital_Images_Slides.pdf\" target=\"_blank\" rel=\"noopener noreferrer\">A PDF version of my PowerPoint presentations<\/a>)<\/li>\n<\/ul>\n<hr \/>\n<p>A Digital Image is a numeric representation, usually binary, of a two-dimensional image.<\/p>\n<p>Creating Digital Images<\/p>\n<ul>\n<li>Scanner<\/li>\n<li>Camera<\/li>\n<li>\u201cBorn Digital\u201d<\/li>\n<\/ul>\n<p>Picture Element (Pixel) \u2013 Smallest element of a digital image<\/p>\n<ul>\n<li>Fewer Pixels \u2013 Low Resolution Image<\/li>\n<li>More Pixels \u2013 High Resolution Image<\/li>\n<\/ul>\n<p>Aspect Ratio \u2013 Ratio of the Width versus the Height of a digital image<\/p>\n<p>Image Types<\/p>\n<ul>\n<li>Black and White\n<ul>\n<li>Threshold defines what is Black or White<\/li>\n<li>Compact &#8211; 1 bit saved for each Pixel<\/li>\n<li>OK for lines and text<\/li>\n<\/ul>\n<\/li>\n<li>Gray Scale\n<ul>\n<li>Palate limited to shades of Gray (equal intensives of Red, Green and Blue)<\/li>\n<li>8-bit color depth \u2013 Shades of Gray in 256 steps<\/li>\n<li>16-bit color depth \u2013 Shades of Gray in 65,536 steps<\/li>\n<li>Good for Black and White images (and lines and text)<\/li>\n<\/ul>\n<\/li>\n<li>Color\n<ul>\n<li>Each pixel is broken down into three primary colors (Red, Green and Blue)<\/li>\n<li>24-bit color depth \u2013 each color has a 8-bit value (0 \u2013 255)<\/li>\n<li>48-bit color depth \u2013 each color has a 16-bit value (0 \u2013 65,536)<\/li>\n<li>Good for images (and lines and text)<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p>Image Size vs. Resolution<\/p>\n<ul>\n<li>Low resolution images cannot be enlarged<\/li>\n<li>If you plan to enlarge images you need to scan at a higher resolution<\/li>\n<li>Effective Resolution \u2013 Pixels per inch\n<ul>\n<li>The optimal Effective Resolution for a image to be printed is about 300 Pixels per inch<\/li>\n<\/ul>\n<\/li>\n<li>Histogram \u2013 shows the number of pixels for each color\n<ul>\n<li>Most useful to photographers<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p>Digital Image File Formats<\/p>\n<ul>\n<li>Lossless\n<ul>\n<li>No digital data is lost or discarded when creating the file<\/li>\n<li>Tends to create large files<\/li>\n<li>Used by archivists and preservationists<\/li>\n<\/ul>\n<\/li>\n<li>Lossy \u2013 Some digital data is lost or discarded when creating the file\n<ul>\n<li>Creates more compact files<\/li>\n<li>Degradation in image quality is acceptable for some uses<\/li>\n<\/ul>\n<\/li>\n<li>TIFF \u2013 Tagged Image File Format\n<ul>\n<li>Lossless<\/li>\n<li>Creates large files<\/li>\n<li>Many browsers will not open TIFF images<\/li>\n<\/ul>\n<\/li>\n<li>PNG\n<ul>\n<li>Performs lossless (i.e., reversable) file compression<\/li>\n<li>Supports Transparent Images<\/li>\n<\/ul>\n<\/li>\n<li>JPEG \u2013 Joint Photographic Experts Group\n<ul>\n<li>Lossy<\/li>\n<li>Degree of compress can be varied\n<ul>\n<li>Less Compression -&gt; Larger files<\/li>\n<li>More Compression -&gt; Smaller files<\/li>\n<\/ul>\n<\/li>\n<li>Does not change the resolution of the image<\/li>\n<li>Compression is performed every time the file is saved\n<ul>\n<li>Each compression further degrades the quality of the image<\/li>\n<\/ul>\n<\/li>\n<li>Does not support Transparent Images<\/li>\n<\/ul>\n<\/li>\n<li>RAW\n<ul>\n<li>A TIFF-like format created by some cameras and camera Apps<\/li>\n<li>Need compatible software to read the files and save as TIFF, JPEG, PNG, etc..<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p>File Conversion<\/p>\n<ul>\n<li>TIFF and PNG can be converted to JPEG<\/li>\n<li>JPEG can be converted to TIFF and PNG\n<ul>\n<li>But the damage done when the JPEG files was initially created cannot be reversed<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p>Metadata<\/p>\n<ul>\n<li>Data about the digital image<\/li>\n<li>Saved with the image<\/li>\n<li>Cameras add additional information<\/li>\n<li>You can add text and tags as well\n<ul>\n<li>Windows and Mac O\/S allow you to access Metadata<\/li>\n<li>XnViewMP is a popular free software tool for managing metadata<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>Most of us don\u2019t know how a JPEG file differs from a TIFF file and whether or not that difference is important. This presentation will provide you with a basic understanding of how images are digitized and will familiarize you<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-1968","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.rayson.us\/aehanson\/wp-json\/wp\/v2\/pages\/1968","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.rayson.us\/aehanson\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.rayson.us\/aehanson\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.rayson.us\/aehanson\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.rayson.us\/aehanson\/wp-json\/wp\/v2\/comments?post=1968"}],"version-history":[{"count":11,"href":"https:\/\/www.rayson.us\/aehanson\/wp-json\/wp\/v2\/pages\/1968\/revisions"}],"predecessor-version":[{"id":2025,"href":"https:\/\/www.rayson.us\/aehanson\/wp-json\/wp\/v2\/pages\/1968\/revisions\/2025"}],"wp:attachment":[{"href":"https:\/\/www.rayson.us\/aehanson\/wp-json\/wp\/v2\/media?parent=1968"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}