How to convert PDF from CMYK to RGB, for displaying on iPad?

Question

According to this question:

Displaying PDF documents on iPad - Color Problems

some PDFs don\'t display right on iOS devices due to colors not being in RGB. It\'s

Answer 1

as far I know, ghostscript is only able to convert colorspace in raster images

podofocolor

http://podofo.sourceforge.net/

is able to convert vector objects

you can try to convert (for black and white non colorful pages), cmyk to grayscale in this way:

podofocolor grayscale input.pdf output.pdf

if binaries are not in repositories, unfortunately you need to build by yourself. however, i just tried to convert a pdf to greyscale with

gs -sOutputFile=output.pdf -sDEVICE=pdfwrite -sColorConversionStrategy=Gray -dProcessColorModel=/DeviceGray -dCompatibilityLevel=1.4 input.pdf < /dev/null

and prepress preflight check said it was turned to grayscale, so, maybe I was wrong saying that gs can only convert colorspace of raster content in a pdf (since my pdf is vectorized)