I am about to send to print my project, to print 1000 copies
I developed the project usign RGB pictures, but manofacturer asked me to use CMYK (of course)
Manofacturer sent me a guide explaining what % of every color (Cyan, Magenta...) I need to prepare.
Do I have to change "one by one" all the pictures in order to conver from RGB to CMYK or is there a standard procedure to save time.
I have more than 500 pictures and I think it would take me several days to prepare,
No need to change your files (in fact don't!), but if this particular vendor will not accept anything but CMYK (dark ages thinking, fwiw). you can convert your colours to CMYK on exporting your PDF. Ideally, this vendor should provide you with a color profile specific to their press to use, but failing that, use what is currently set as your CMYK profile in your Color settings (if yours is set at the default when installed it may be US Web Coated (which is pretty old school)... better yet, use a generally-accepted modern one, e.g GRACOL as in my example.
Change the section of Output from "No Color Conversion" to "Convert to Destination (Preserve Numbers)". This will convert all your documents RGB values to the closest possible value into CMYK values. (*The Preserve Numbers is added to make sure any colors you already have in your document that are already CMYK do not get changed).
Before you do this, it's a good practice to do a visual check on screen (soft proof) to see what difference between your RGB and what you will get in CMYK based on the profile you are converting to: Under View: set your color profile (e.g. GRACOL or whatever), then toggle the Proof Colors to go from RGB <> CMYK. This is particlarly useful to see where out of gamut colours (like bright blues and intense pinks) will land in CMYK.