diff --git a/TODO b/TODO
index abc27fcc..33ecf8c1 100644
--- a/TODO
+++ b/TODO
@@ -1,11 +1,3 @@
-
-- does vips_interpolate_binlinear_static() stioll exist? add a note to
-  VipsInterpolate.3 if it does
-
-  manual too?
-
-- im_gauss_imask_sep needs docs, C++ docs as well
-
 WONTFIX for 7.18
 ================
 
diff --git a/doc/src/interpolate.tex b/doc/src/interpolate.tex
index dfefc7a2..17148cdf 100644
--- a/doc/src/interpolate.tex
+++ b/doc/src/interpolate.tex
@@ -132,3 +132,32 @@ VipsInterpolateMethod
 
 You can build an instance of a \verb+VipsInterpolator+ with
 the \verb+vips_object_*()+ family of functions, see \pref{sec:object}.
+
+Convenience functions return a static instance of one of the standard
+interpolators:
+
+\begin{verbatim}
+VipsInterpolate *vips_interpolate_nearest_static( void );
+VipsInterpolate *vips_interpolate_bilinear_static( void );
+VipsInterpolate *vips_interpolate_bicubic_static( void );
+\end{verbatim}
+
+\noindent
+Don't free the result.
+
+Finally, \verb+vips_interpolate_new()+ makes a \verb+VipsInterpolate+ from a
+nickname:
+
+\begin{verbatim}
+VipsInterpolate *vips_interpolate_new( const char *nickname );
+\end{verbatim}
+
+For example:
+
+\begin{verbatim}
+VipsInterpolate *interpolate = vips_interpolate_new( "nohalo" );
+\end{verbatim}
+
+\noindent
+You must drop your ref after you're done with the object with
+\verb+g_object_unref()+.
diff --git a/doc/src/vmask.tex b/doc/src/vmask.tex
index 4f0a8871..57b5ce0c 100644
--- a/doc/src/vmask.tex
+++ b/doc/src/vmask.tex
@@ -129,6 +129,7 @@ operator VImage();
 
 // Build gaussian and log masks
 static VIMask gauss( double, double );
+static VIMask gauss_sep( double, double );
 static VIMask log( double, double );
 
 // Rotate
diff --git a/man/Makefile.am b/man/Makefile.am
index cc1fb99d..0c776f32 100644
--- a/man/Makefile.am
+++ b/man/Makefile.am
@@ -205,6 +205,7 @@ man_MANS = \
 	im_gammacorrect.3 \
 	im_gauss_dmask.3 \
 	im_gauss_imask.3 \
+	im_gauss_imask_sep.3 \
 	im_gaussnoise.3 \
 	im_gbandjoin.3 \
 	im_generate.3 \
diff --git a/man/VipsInterpolate.3 b/man/VipsInterpolate.3
index 0dae44c7..34747f93 100644
--- a/man/VipsInterpolate.3
+++ b/man/VipsInterpolate.3
@@ -33,6 +33,14 @@ VipsInterpolateMethod vips_interpolate_get_method( VipsInterpolate * );
 .br
 int vips_interpolate_get_window_size( VipsInterpolate *interpolate );
 
+VipsInterpolate *vips_interpolate_nearest_static( void );
+.br
+VipsInterpolate *vips_interpolate_bilinear_static( void );
+.br
+VipsInterpolate *vips_interpolate_bicubic_static( void );
+
+VipsInterpolate *vips_interpolate_new( const char *nickname );
+
 .SH DESCRIPTION
 .B VipsInterpolate
 is the base class for VIPS interpolators. It provides a simple framework that
@@ -58,6 +66,22 @@ either calls
 or if it is NULL, returns 
 .B window_size.
 
+.B vips_interpolate_nearest_static(3),
+.B vips_interpolate_bilinear_static(3)
+and
+.B vips_interpolate_bicubic_static(3)
+are convenience functions which return a pointer to a static instance of a
+nearest-neighbour, bilinear and bicubic interpolator. You can pass these to
+any function which needs a 
+.B VipsInterpolator
+as an argument. No need to free the result.
+
+.B vips_interpolate_new(3)
+is a convenience function which makes an interpolator from a nickname. Free
+the result with 
+.B g_object_unref(3)
+when you're done with it.
+
 .SH SUPPORTED INTERPOLATORS
 
 You can list the supported interpolators with
diff --git a/man/im_gauss_dmask.3 b/man/im_gauss_dmask.3
index 37c3a33f..e22e257b 100644
--- a/man/im_gauss_dmask.3
+++ b/man/im_gauss_dmask.3
@@ -15,6 +15,13 @@ double sigma, min_amplitude;
 char *name;
 .br
 double sigma, min_amplitude;
+
+.B INTMASK im_gauss_imask_sep( name, sigma, min_amplitude )
+.br
+char *name;
+.br
+double sigma, min_amplitude;
+
 .SH DESCRIPTION
 Both functions create a circularly symmetric Gaussian mask of sigma.  The size
 of the mask is determined by the variable min_amplitude; if for instance the
@@ -30,17 +37,25 @@ The program uses the following equation:
 The generated mask has odd size and its maximum value is normalised to
 either 100 (gauss_imask) or to 1.0 (gauss_dmask).
 
-.B im_gauss_dmask()
+.B im_gauss_dmask(3)
 creates a DOUBLEMASK laplacian of Gaussian mask with maximum value normalised 
 to 1.0.
 
-.B im_gauss_imask()
+.B im_gauss_imask(3)
 creates a INTMASK laplacian of Gaussian mask with maximum value normalised
 to 100.
+
+.B im_gauss_imask_sep(3)
+returns the centre line of 
+.B im_gauss_imask(3). 
+It is convenient for use with
+.B im_conv_sep(3)
+for building fast gaussian blur or sharpen.
+
 .SH RETURNED VALUE:
 The functions return NULL on erorr.
 .SH SEE ALSO
-im_log_dmask(3), im_conv(3)
+im_log_dmask(3), im_conv(3), im_conv_sep(3).
 .SH COPYRIGHT
 .br
 N. Dessipris
diff --git a/man/im_gauss_imask_sep.3 b/man/im_gauss_imask_sep.3
new file mode 100644
index 00000000..dca741eb
--- /dev/null
+++ b/man/im_gauss_imask_sep.3
@@ -0,0 +1 @@
+.so man3/im_gauss_dmask.3