InDesign has to be my favourite Adobe application. I like to view it as my home ground, where I can take anything I’ve made in Photoshop or Illustrator and place it for its final intended use. It’s also great in how you can combine it with other great functions like Photoshop actions to speed up processes, like taking a draft brochure and making it print ready. In such a case, I would create a great Photoshop action that turns my supplied JPG files into CMYK TIFFs and drops them into my InDesign links folder.
This is the point where InDesign can do the hard work on your behalf. You’ve got nicely placed, non-print-ready JPGs and new CMYK TIFFs of the same files, that need to link into the Indesign document in exactly the same place as the exisiting JPG. In your links panel, filter your images by Colour Space (or other useful filter) to collate the images you actually want to update and select them. From here, click the small drop down arrow in the top right and choose Relink To Folder. You may see that there is an option to Relink File Extension, which is useful, but only for one graphic at a time.
Within Relink to Folder, you get to find the folder where your new graphics are located. If you placed your new files in the same folder as your old files, it’s probably the currently selected folder. If you’ve put them somewhere else (hopefully somewhere within your Links folder, keeping your files tidy is important) simply find the folder they’re located in. At the bottom of this window, look for the radio button that says Match Same Filename But This Extension. It comes with a little text box where you can specify the new extension that you want InDesign to look for, which in most cases for me, is TIF. Hit Choose to finish this process.
All being well, your images have changed from JPGs to TIFFs and are a neat and tidy 300dpi if you were preparing your images for print like I am. I like to keep multiple versions of my documents (it never hurts to) so I Save As to make a copy that I reference as being CMYK ready. You can take this a step further too, and File, Package your document– it’s super handy to get the program to collate all of your new files in one place, and ignore anything that’s no longer linked to this new version of the document.