Differences

This shows you the differences between two versions of the page.

--- doc:appunti:hardware:canoscan_9000f_mark_ii [2014/11/18 21:32] – [Invert and color balance] niccolo
+++ doc:appunti:hardware:canoscan_9000f_mark_ii [2018/01/04 11:57] – [Web references] niccolo
@@ Line 231: / Line 231: @@
 We choose by visual inspection the best value for gamma; 0.007 in this example.
-Then we open with Gimp a sample photo, we need a shot with good **black**, **gray** and **white** spots. The process is:
+Thake a film strip (negated and gamma-corrected with the above recipe) and open it with the Gimp. We need a strip with good **black**, **gray** and **white** spots. The process is:
   - Apply a **pixelize blur filter** on the black, gray and white spots. Make it large enough so you can easly pick the color from it in the next steps.
@@ Line 282: / Line 282: @@
   - Repeat the last two steps.
+===== ImageMagick convert, memory issue =====
+Executing **convert** on very large images can lead to memory exhausted issue. I experienced it converting a TIF scan into PNG (because I wish to avoid 24 bit Gimp limitation with TIF images):
+<code>
+convert very-big.tif very-big.png
+convert-im6.q16: DistributedPixelCache '127.0.0.1' @ error/distribute-cache.c/ConnectPixelCacheServer/244.
+convert-im6.q16: cache resources exhausted `very-big.png' @ error/cache.c/OpenPixelCache/3945.
+convert-im6.q16: No IDATs written into file `very-big.png' @ error/png.c/MagickPNGErrorHandler/1628.
+</code>
+It seems that ImageMagick is self-limiting the disk resource it will use, you can fix the configuration file **''/etc/ImageMagick-6/policy.xml''**, increasing the **1GiB** limit:
+<code xml>
+<policymap>
+  <policy domain="resource" name="memory" value="256MiB"/>
+  <policy domain="resource" name="map" value="512MiB"/>
+  <policy domain="resource" name="width" value="16KP"/>
+  <policy domain="resource" name="height" value="16KP"/>
+  <policy domain="resource" name="area" value="128MB"/>
+  <policy domain="resource" name="disk" value="1GiB"/>
+</policymap>
+</code>
+May be you can also increase the Memory resource, if you have enough:
+<code>
+convert -list resource
+Resource limits:
+  Width: 16KP
+  Height: 16KP
+  Area: 128MP
+  Memory: 256MiB
+  Map: 512MiB
+  Disk: 1GiB
+  File: 768
+  Thread: 2
+  Throttle: 0
+  Time: unlimited
+</code>
 ===== Web references =====
@@ Line 288: / Line 329: @@
   * [[http://125px.com/articles/photography/digital/colorneg/|Thoughts on Color Negative Scanning]]
   * [[https://sites.google.com/site/negfix/|Negfix8 scrip]] to turn scanned negative image into the positive image.
+  * [[https://zephyrsoft.org/blog/34-digitize-slides-and-prints-on-linux|Use Canon CanoScan 9000F Mark II to digitize slides and prints on Linux]], with some useful tips about doing crop and trim with Imagemagick, etc.