{"id":4258,"date":"2010-10-26T05:55:12","date_gmt":"2010-10-26T09:55:12","guid":{"rendered":"http:\/\/www.johnpaulcaponigro.com\/blog\/?p=4258"},"modified":"2010-10-26T05:55:12","modified_gmt":"2010-10-26T09:55:12","slug":"reduce-noise-with-dark-slides","status":"publish","type":"post","link":"https:\/\/www.johnpaulcaponigro.com\/blog\/4258\/reduce-noise-with-dark-slides\/","title":{"rendered":"Reduce Noise With Dark Slides"},"content":{"rendered":"

\"\"<\/a>
\nSome noise is random; some noise is fixed. Hot-pixel noise is fixed. What are \u201chot pixels\u201d? Photosites on digital sensors that generate brighter information faster than their neighbors. Hot pixels get brighter at higher ISOs, with longer exposures, and in warmer temperatures. You can map where hot pixels are and exactly how bright they get under specific conditions with a dark slide. Then you can use a dark slide to drop out fixed \u201chot-pixel\u201d noise with a simple postprocessing technique in Photoshop.
\nTo make a dark slide, simply make a separate exposure made at the same ISO, exposure time and temperature as the image you intend to use it with. Exposure of what? Darkness. Leave your lens cap on.
\nTo use a dark slide in Photoshop, open the dark slide and the image you\u2019d like to use it with and drag and drop the dark slide into that image file, holding the Shift key to make sure it\u2019s precisely registered (wait to crop or rotate an image until after this is accomplished). Change the blend mode of the dark-slide layer to Difference and watch the hot-pixel noise vanish.
\nLearn more about making and using dark slides on Digital Photo Pro.<\/a>
\nLearn more about noise here.<\/a>
\nLearn more in my digital printing workshops.<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

Some noise is random; some noise is fixed. Hot-pixel noise is fixed. What are \u201chot pixels\u201d? Photosites on digital sensors that generate brighter information faster than their neighbors. Hot pixels get brighter at higher ISOs, with longer exposures, and in warmer temperatures. You can map…<\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"spay_email":"","jetpack_publicize_message":"","jetpack_is_tweetstorm":false,"jetpack_publicize_feature_enabled":true},"categories":[964,12],"tags":[2032,1068,1771,141],"post_folder":[],"yoast_head":"\nReduce Noise With Dark Slides - John Paul Caponigro<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.johnpaulcaponigro.com\/blog\/4258\/reduce-noise-with-dark-slides\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Reduce Noise With Dark Slides - John Paul Caponigro\" \/>\n<meta property=\"og:description\" content=\"Some noise is random; some noise is fixed. Hot-pixel noise is fixed. What are \u201chot pixels\u201d? Photosites on digital sensors that generate brighter information faster than their neighbors. Hot pixels get brighter at higher ISOs, with longer exposures, and in warmer temperatures. You can map...\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.johnpaulcaponigro.com\/blog\/4258\/reduce-noise-with-dark-slides\/\" \/>\n<meta property=\"og:site_name\" content=\"John Paul Caponigro\" \/>\n<meta property=\"article:published_time\" content=\"2010-10-26T09:55:12+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/www.johnpaulcaponigro.com\/blog\/wp-content\/uploads\/2021\/02\/noisedarkslides.jpg\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"johnpaulcaponigro\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"1 minute\" \/>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"Reduce Noise With Dark Slides - John Paul Caponigro","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/www.johnpaulcaponigro.com\/blog\/4258\/reduce-noise-with-dark-slides\/","og_locale":"en_US","og_type":"article","og_title":"Reduce Noise With Dark Slides - John Paul Caponigro","og_description":"Some noise is random; some noise is fixed. Hot-pixel noise is fixed. What are \u201chot pixels\u201d? Photosites on digital sensors that generate brighter information faster than their neighbors. Hot pixels get brighter at higher ISOs, with longer exposures, and in warmer temperatures. 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