If you use Photoshop CS4-CS6 64 bit on Win 64 bit
Copy the files with the ending _64.8bf into the Plugins folder of Photoshop CS4-CS6.
For example, to add the Coloriage plugin to Photoshop CS5:
Copy Coloriage_64.8bf from the corresponding folder C:\Program Files (x86)\AKVIS\Coloriage
into the Plug-ins folder of Photoshop: C:\Program Files\Adobe\Adobe Photoshop CS6 (64 Bit)\Plug-ins\
Then re-open Photoshop and check how the plugin works.
If you use Photoshop CS4-CS6 32 bit on Win 64 bit
Copy the files with the ending .8bf into the Plugins folder of Photoshop CS4-CS6.
For example, Coloriage.8bf from the corresponding folder C:\Program Files (x86)\AKVIS\Coloriage
into the Plug-ins folder of Photoshop: C:\Program Files (x86)\Adobe\Adobe Photoshop CS6\Plug-ins\
Then re-open Photoshop and check how the plugin works.
Attention!
If you set the Additional Plug-ins Folder in Photoshop (using the command Edit -> Preferences -> Plug-Ins), to add the path to a folder with plug-ins in Photoshop 32 bit on Windows 64 bit, you can get an error message from Photoshop that it does not know that kind of file.
It happens if the folder has a 64 bit plugin. Photoshop 32 bit tries to upload it but can't recognize it.
Not a big problem, but it's very irritating to get the error message each time you run Photoshop. To remove this error message just delete the 64 bit file from the folder used as the Additional Plug-ins Folder in Photoshop preferences. If you use Photoshop 32 bit you do not need 64 bit files there.
Photoshop PlugIns in Windows 64 bit