Hi, I would like to get the value type of the channels depending on an image view. So I can get the scoped channel type, from MyView type, like this: typedef typename boost::gil::channel_type<MyView>::type MyScopedChannel; But I can't get the primitive type used by the scoped channel. For example, if the type is scoped_channel_value<float,float_zero,float_one>, I can't get the float type. /// \ingroup ScopedChannelValue /// \brief A channel adaptor that modifies the range of the source channel. Models: ChannelValueConcept template <typename BaseChannelValue, // base channel (models ChannelValueConcept) typename MinVal, typename MaxVal> // classes with a static apply() function returning the minimum/maximum channel values struct scoped_channel_value { typedef BaseChannelValue base_channel_t; //< missing typedef //... } So this will allows to use: typedef typename boost::gil::channel_type<MyView>::type::base_channel_t ChannelBaseType; Are you agree to add this typedef ? Best regards, Fabien Castan