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doc:appunti:hardware:canoscan_9000f_mark_ii_positive_scan [2019/12/23 16:10] – [Imagemagick tools] niccolodoc:appunti:hardware:canoscan_9000f_mark_ii_positive_scan [2020/01/02 17:40] (current) – [Imagemagick tools] niccolo
Line 9: Line 9:
  
 <code bash> <code bash>
 +#!/bin/sh
 +
 FORMAT='tiff' FORMAT='tiff'
 RESOLUTION='1200' RESOLUTION='1200'
Line 23: Line 25:
 </code> </code>
  
-When you will open the image into GIMP, you will asked if you want to convert the pixel values from the **custom Canon color space**, to the **standard sRGB** color space. Keeping the image into its original format (16 bit and original color space) is the best option if you want to keep all the numerical data for future image manipulation. Converting to another color space (sRGB is the one suggested by GIMP) will speed-up the handling of the image, but it is an **lossy on-way operation** due numerical **approximation errors** and due differences in **color space extensions**.+When you will open the image into GIMP, you will asked if you want to convert the pixel values from the **custom Canon color space**, to the **standard sRGB** color space. Keeping the image into its original format (16 bit and original color space) is the best option if you want to keep all the numerical data for future image manipulation. Converting to another color space (sRGB is the one suggested by GIMP) will speed-up the handling of the image, but it is an **lossy one-way operation** due numerical **approximation errors** and due differences in **color space extensions**.
  
 The GIMP is rather good in handling various image formats with custom color profiles, but beware that not all the viewers are equally capable. E.g. the **Geeqie 1.4** image viewer **does not apply** custom ICC profiles **to JPEG images**, so it will display images as //RAW data// (bad colors). Images for the web generally do not embed a custom color profile, they are expected to be into the sRGB color space, compressed as JPEG 24 bit (8 bit per channel). The GIMP is rather good in handling various image formats with custom color profiles, but beware that not all the viewers are equally capable. E.g. the **Geeqie 1.4** image viewer **does not apply** custom ICC profiles **to JPEG images**, so it will display images as //RAW data// (bad colors). Images for the web generally do not embed a custom color profile, they are expected to be into the sRGB color space, compressed as JPEG 24 bit (8 bit per channel).
-===== ICC profile =====+===== The Canon 9000F ICC profile =====
  
 An **[[wp>ICC Profile]]** specifies a set of rules to transform the graphics data (the color values of each pixel) from the source (the scanner in our case) to a target (e.g. the scren). The mappings may be specified using **tables**, to which **interpolation** is applied, or through a series of **parameters** for **function** transformations. An **[[wp>ICC Profile]]** specifies a set of rules to transform the graphics data (the color values of each pixel) from the source (the scanner in our case) to a target (e.g. the scren). The mappings may be specified using **tables**, to which **interpolation** is applied, or through a series of **parameters** for **function** transformations.
Line 35: Line 37:
  
 For the **Canon CanoScan 9000F Mark II** there is, available on the net, a color profile made by an unknown author, here you can find a copy: **{{.:canon-900f:canon_9000f_mark_ii_icc.tgz|canon_9000f_mark_ii_icc.tgz}}**. Originally I found the file on [[https://archive.org/details/canon9000fmarkiiiccicm|archive.org]]. For the **Canon CanoScan 9000F Mark II** there is, available on the net, a color profile made by an unknown author, here you can find a copy: **{{.:canon-900f:canon_9000f_mark_ii_icc.tgz|canon_9000f_mark_ii_icc.tgz}}**. Originally I found the file on [[https://archive.org/details/canon9000fmarkiiiccicm|archive.org]].
 +
 ===== Imagemagick tools ===== ===== Imagemagick tools =====
  
-The **Imagemagick** package provides several tools that can be used for several tasks: +See the page **[[..:software:imagemagick_color_management]]**.
- +
-  * **Inspect** the file format. +
-  * **Convert** to and from various formats. +
-  * Apply, change or strip **color profiles**. +
- +
-=== Inspect a file === +
- +
-This command display the image format, bit depth, colorspace, embeddedd ICC profile, max and min values of the color components, etc. +
- +
-<code> +
-identify -verbose image.tiff +
-Image: image.tiff +
-  ... +
-  Colorspace: sRGB +
-  ... +
-  Depth: 16-bit +
-  ... +
-  Channel statistics: +
-    Pixels: 1572864 +
-    Red: +
-      min: 1024  (0.0156252) +
-      max: 64005 (0.976654) +
-      mean: 22070.8 (0.336779) +
-      standard deviation: 20844.1 (0.318061) +
-      ... +
-</code> +
- +
-When you convert an image from a colorspace to another, you can check how much the max and min values for each channel have changed, etc. +
- +
-You can also extract just the parameter you need: +
- +
-<code> +
-convert image.tiff -print "%[colorspace]\n" null: +
-convert image.tiff -print "%[profiles]\n" null: +
-convert image.tiff -print "%[profile:icc]\n" null: +
-</code> +
- +
-=== Add a color profile to an image === +
- +
-This command will **strip** any comment and **profile** from a source image, then it adds a color profile from an ICC file, **embedding** it into the image, **without altering the pixel data** values (**WARNING**: it will remove the //Exif.Photo.UserComment// comment too): +
- +
-<code> +
-convert image.tiff -strip -profile canon9000fmarkii.icc image-profile-canon.tiff +
-</code> +
- +
-=== Convert an image to another color profile === +
- +
-The following command will ignore any embedded profile (-strip), **apply the Canon custom profile**, than **convert** the image to the **standard sRGB color profile** (color space). Finally it removes from the resulting image any metadata about profile: +
- +
-<code> +
-convert image.tiff -strip -profile canon9000fmarkii.icc -profile sRGB.icc -strip image-srgb.tiff +
-</code> +
- +
-The resulting image will not have any metadata about color profile, so the sRGB will be assumed by default. The pixel data values are converted from the original Canon colorspace to the sRGB one (one-way lossy operation). +
- +
-**NOTICE**: the Debian package **colord-data** provides the file **/usr/share/color/icc/colord/sRGB.icc**. +
- +
-=== Extract an embedded color profile from an image === +
- +
-This command will extract the ICC file embedded into a file: +
- +
-<code> +
-convert image.tiff image-color-profile.icc +
-</code> +
- +
-It is not possible to extract the ICC file if the colorspace is just declared into the metadata, but not embedded as a profile. In this case you can search instead into the **/usr/share/color/icc/colord/** folder for well-known ICC files installed by the **colord-data** package. +
- +
-=== Set a different colorspace === +
- +
-This command will change the colorspace of an image. Just **the metadata is changed**, no data conversion is performed: +
- +
-<code> +
-convert image.tiff -set colorspace RGB    image_rgb.png +
-convert image.tiff -set colorspace CIELab image_lab.tiff +
-</code> +
- +
-While the source image is into the **sRGB** colorspace, the created files will be into the **RGB** and **CIELab** ones: +
- +
-<code> +
-convert image.tiff     -print "%[colorspace]\n" null: +
-# >>> sRGB +
-convert image_rgb.png  -print "%[colorspace]\n" null: +
-# >>> RGB +
-convert image_lab.tiff -print "%[colorspace]\n" null: +
-# >>> CIELab +
-</code> +
- +
-**NOTICE** that some combinations of **image format** and **colorspace** are not allowed, e.g. you cannot create a TIFF file into the RGB colorspace, or a PNG file into the CIELab colorspace.+
doc/appunti/hardware/canoscan_9000f_mark_ii_positive_scan.1577113803.txt.gz · Last modified: 2019/12/23 16:10 by niccolo