The only free version of SILKYPIX Developer Studio is for PENTAX and in order to obtain a link to download this version you need to go at Software Informer review page of the product and click Download green button.
On Ichikawa Soft Laboratory, the developer of SILKYPIX Developer Studio, download page, you can find all versions of SILKYPIX Developer Studio. You can download the 3.0 trial version downside the page.