Spektrafilm analog film simulation module

RELEASE_NOTES.md

@@ -49,7 +49,7 @@ for more information on how to contribute._
 ## The Big Ones
 
 The following is a summary of the main features added to darktable
-5.6. Please see the user manual for more details of the individual
+5.8. Please see the user manual for more details of the individual
 changes (where available).
 
 - Automatic alignment of exposure brackets in "merge HDR" function,
@@ -67,6 +67,12 @@ changes (where available).
   by fixed offsets, so a stack stays valid across module versions, and
   renders run on a throwaway duplicate so the source image is never
   modified.
+
+- A new analog film simulation module, based on the [spektrafilm](https://github.com/andreavolpato/spektrafilm) 
+  project by Andrea Volpato. It simulates the physical photographic 
+  process from film exposure and development through printing and 
+  scanning, including film grain, halation and diffusion. 
+
 
 ## UI/UX Improvements
 

data/darktableconfig.xml.in

@@ -2780,6 +2780,20 @@
     <shortdescription>crossover ISO for X-Trans FDC demosaicing</shortdescription>
     <longdescription>up to, and including, this ISO, X-Trans frequency domain chroma demosaicing uses the hybrid mode for determining chroma; for all higher ISO values the pure FDC is used.</longdescription>
   </dtconfig>
+  <dtconfig>
+    <name>plugins/darkroom/spektrafilm/repository</name>
+    <type>string</type>
+    <default>darktable-org/darktable-spektrafilm</default>
+    <shortdescription>spektrafilm data repository</shortdescription>
+    <longdescription>repository holding the spektrafilm spectral data packs, as owner/repo. the files are read over https; git is not required.</longdescription>
+  </dtconfig>
+  <dtconfig>
+    <name>plugins/darkroom/spektrafilm/ref</name>
+    <type>string</type>
+    <default>main</default>
+    <shortdescription>spektrafilm data repository ref</shortdescription>
+    <longdescription>tag or branch to read the spektrafilm data packs from. a tag is preferable where one exists: an immutable ref is what lets an old edit fetch the exact spectral table it was developed against, where a branch hands over whatever is current.</longdescription>
+  </dtconfig>
   <dtconfig>
     <name>plugins/darkroom/denoiseprofile/show_compute_variance_mode</name>
     <type>bool</type>
@@ -4064,13 +4078,14 @@
         <option>scene-referred (sigmoid)</option>
         <option>scene-referred (filmic)</option>
         <option>scene-referred (AgX)</option>
+        <option>scene-referred (spektrafilm)</option>
         <option>display-referred (legacy)</option>
         <option>none</option>
       </enum>
     </type>
     <default>scene-referred (sigmoid)</default>
     <shortdescription>auto-apply pixel workflow defaults</shortdescription>
-    <longdescription><![CDATA[selects which workflow will be used by default in the darkroom\n\n<b>scene-referred (sigmoid)</b> modern workflow, fewer tonemapper controls\n\n<b>scene-referred (filmic)</b> modern workflow, more tone mapping controls\n\n<b>scene-referred (AgX)</b> modern workflow, maximum tone mapping control\n\n<b>display-referred (legacy)</b> legacy workflow (not recommended)\n\n<b>none</b> do not use a predefined workflow]]></longdescription>
+    <longdescription><![CDATA[selects which workflow will be used by default in the darkroom\n\n<b>scene-referred (sigmoid)</b> modern workflow, fewer tonemapper controls\n\n<b>scene-referred (filmic)</b> modern workflow, more tone mapping controls\n\n<b>scene-referred (AgX)</b> modern workflow, maximum tone mapping control\n\n<b>scene-referred (spektrafilm)</b> modern workflow, the tone mapping done by a simulated film and print\n\n<b>display-referred (legacy)</b> legacy workflow (not recommended)\n\n<b>none</b> do not use a predefined workflow]]></longdescription>
     <welcomescreen pagenum="1" questionnum="1"/>
   </dtconfig>
   <dtconfig prefs="processing" section="general">

data/kernels/programs.conf

@@ -43,3 +43,4 @@ agx.cl                  39
 colorharmonizer.cl      40
 overlay.cl              41
 bilinear.cl             42
+spektrafilm.cl          43