diff --git a/DESCRIPTION b/DESCRIPTION
index de95b1a..06fe99e 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -25,5 +25,5 @@ Suggests:
     webp,
     tesseract,
     testthat
-RoxygenNote: 6.1.1
+RoxygenNote: 7.0.2
 Roxygen: list(markdown = TRUE)
diff --git a/R/render.R b/R/render.R
index b7ed10d..b7fec44 100644
--- a/R/render.R
+++ b/R/render.R
@@ -20,6 +20,8 @@
 #' # convert few pages to png
 #' file.copy(file.path(Sys.getenv("R_DOC_DIR"), "NEWS.pdf"), "news.pdf")
 #' pdf_convert("news.pdf", pages = 1:3)
+#' # specify format string for output filenames
+#' pdf_convert("news.pdf", filenames="news_page_%d.%s")
 #'
 #' # render into raw bitmap
 #' bitmap <- pdf_render_page("news.pdf")
@@ -62,7 +64,8 @@ pdf_render_page<- function(pdf, page = 1, dpi = 72, numeric = FALSE, antialias =
 #' to one of `poppler_config()$supported_image_formats`.
 #' @param pages vector with one-based page numbers to render. `NULL` means all pages.
 #' @param filenames vector of equal length to `pages` with output filenames. May also be
-#' a format string which is expanded using `pages` and `format` respectively.
+#' a format string which is expanded using `pages` and `format` respectively, i.e. `sprintf`-type
+#' string containing `%d` and `%s` (in this order).
 #' @param verbose print some progress info to stdout
 pdf_convert <- function(pdf, format = "png", pages = NULL, filenames = NULL , dpi = 72,
                         antialias = TRUE, opw = "", upw = "", verbose = TRUE){
diff --git a/man/pdf_ocr.Rd b/man/pdf_ocr.Rd
index 3623e1b..3417b76 100644
--- a/man/pdf_ocr.Rd
+++ b/man/pdf_ocr.Rd
@@ -5,11 +5,23 @@
 \alias{pdf_ocr_data}
 \title{OCR text extraction}
 \usage{
-pdf_ocr_text(pdf, pages = NULL, opw = "", upw = "",
-  language = "eng", dpi = 600)
+pdf_ocr_text(
+  pdf,
+  pages = NULL,
+  opw = "",
+  upw = "",
+  language = "eng",
+  dpi = 600
+)
 
-pdf_ocr_data(pdf, pages = NULL, opw = "", upw = "",
-  language = "eng", dpi = 600)
+pdf_ocr_data(
+  pdf,
+  pages = NULL,
+  opw = "",
+  upw = "",
+  language = "eng",
+  dpi = 600
+)
 }
 \arguments{
 \item{pdf}{file path or raw vector with pdf data}
@@ -29,7 +41,9 @@ languge of the engine.}
 Perform OCR text extraction. This requires you have the \code{tesseract} package.
 }
 \seealso{
-Other pdftools: \code{\link{pdftools}}, \code{\link{qpdf}},
-  \code{\link{rendering}}
+Other pdftools: 
+\code{\link{pdftools}},
+\code{\link{qpdf}},
+\code{\link{rendering}}
 }
 \concept{pdftools}
diff --git a/man/pdf_render_page.Rd b/man/pdf_render_page.Rd
index aef162d..ab26cbc 100644
--- a/man/pdf_render_page.Rd
+++ b/man/pdf_render_page.Rd
@@ -8,11 +8,27 @@
 \alias{poppler_config}
 \title{Render / Convert PDF}
 \usage{
-pdf_render_page(pdf, page = 1, dpi = 72, numeric = FALSE,
-  antialias = TRUE, opw = "", upw = "")
-
-pdf_convert(pdf, format = "png", pages = NULL, filenames = NULL,
-  dpi = 72, antialias = TRUE, opw = "", upw = "", verbose = TRUE)
+pdf_render_page(
+  pdf,
+  page = 1,
+  dpi = 72,
+  numeric = FALSE,
+  antialias = TRUE,
+  opw = "",
+  upw = ""
+)
+
+pdf_convert(
+  pdf,
+  format = "png",
+  pages = NULL,
+  filenames = NULL,
+  dpi = 72,
+  antialias = TRUE,
+  opw = "",
+  upw = "",
+  verbose = TRUE
+)
 
 poppler_config()
 }
@@ -38,7 +54,8 @@ to one of \code{poppler_config()$supported_image_formats}.}
 \item{pages}{vector with one-based page numbers to render. \code{NULL} means all pages.}
 
 \item{filenames}{vector of equal length to \code{pages} with output filenames. May also be
-a format string which is expanded using \code{pages} and \code{format} respectively.}
+a format string which is expanded using \code{pages} and \code{format} respectively, i.e. \code{sprintf}-type
+string containing \verb{\%d} and \verb{\%s} (in this order).}
 
 \item{verbose}{print some progress info to stdout}
 }
@@ -51,6 +68,8 @@ raw bitmap array for further processing in R.
 # convert few pages to png
 file.copy(file.path(Sys.getenv("R_DOC_DIR"), "NEWS.pdf"), "news.pdf")
 pdf_convert("news.pdf", pages = 1:3)
+# specify format string for output filenames
+pdf_convert("news.pdf", filenames="news_page_\%d.\%s")
 
 # render into raw bitmap
 bitmap <- pdf_render_page("news.pdf")
@@ -73,7 +92,9 @@ unlink(c('news.pdf', 'news_1.png', 'news_2.png', 'news_3.png',
  'page.jpeg', 'page.png', 'page.webp'))
 }
 \seealso{
-Other pdftools: \code{\link{pdf_ocr_text}},
-  \code{\link{pdftools}}, \code{\link{qpdf}}
+Other pdftools: 
+\code{\link{pdf_ocr_text}()},
+\code{\link{pdftools}},
+\code{\link{qpdf}}
 }
 \concept{pdftools}
diff --git a/man/pdftools.Rd b/man/pdftools.Rd
index f5119ad..0ca3c94 100644
--- a/man/pdftools.Rd
+++ b/man/pdftools.Rd
@@ -63,7 +63,9 @@ fonts <- pdf_fonts(pdf_file)
 files <- pdf_attachments(pdf_file)
 }
 \seealso{
-Other pdftools: \code{\link{pdf_ocr_text}},
-  \code{\link{qpdf}}, \code{\link{rendering}}
+Other pdftools: 
+\code{\link{pdf_ocr_text}()},
+\code{\link{qpdf}},
+\code{\link{rendering}}
 }
 \concept{pdftools}
diff --git a/man/qpdf.Rd b/man/qpdf.Rd
index 51033fa..b39ab51 100644
--- a/man/qpdf.Rd
+++ b/man/qpdf.Rd
@@ -11,8 +11,10 @@
 \alias{pdf_subset}
 \title{qpdf utilities}
 \seealso{
-Other pdftools: \code{\link{pdf_ocr_text}},
-  \code{\link{pdftools}}, \code{\link{rendering}}
+Other pdftools: 
+\code{\link{pdf_ocr_text}()},
+\code{\link{pdftools}},
+\code{\link{rendering}}
 }
 \concept{pdftools}
 \keyword{internal}