Thanks for that encouraging reply, Rob. Can I ask a quick supplementary? I have colour jpgs, not particularly high res but neither are they poor. And I'm making a pdf for submission to a printer, to be printed in b/w. The jpgs are atthe moment much bigger than I need: I'll have to scale them to about 40%. Should I process the jpgs into monochrome tiffs? Or would the conversion cost me definition?
On Mon, 2010-01-25 at 11:20 -0700, Rob Oakes wrote: > Hi Richard, > > What kinds of photos are they? For example, are they screenshots that > you've converted to black and white? Or are they text on a white > background? Or are they grayscale images or are they true black and white > (two-tone images)? > > Are there any pertinent details that you wish to highlight? What kind of > contrast values are you hoping to get? What is the initial resolution? Do > you have high-res copies for printing on a press or will you be printing > from a desktop computer? > > The answer to your original question really depends on what you want to do > with them. My experience with LyX has been that it does a pretty good job > with whatever images you feed to it, but it isn't a photo manipulation > program. All of the manipulation should happen to the input images before > you compile into a DVI or PDF. After that, you will need to make the > changes to the PDF in a program like Inkscape, Acrobat Professional, or > Illustrator. > > In general, however, I would recommend that you use TIFF images for black + > white and grayscale (either uncompressed or lossless compression). > Greyscale images are much smaller than color images with only a single > channel of information. In contrast, color images often have three or four > channels of information. Since they contain much less data, using lossy > compression (such as JPEG) doesn't result in a much smaller image size. > > Additionally, JPEG and other compressed image formats will often introduce > distortions. While this won't be visible if printing on a desktop printer > or viewing on screen, it is a terribly bad idea to use low resolution or > compressed images in a file bound for a printing press. > > For graphs and other data graphics, I would highly recommend creating either > an EPS or PDF image. When doing so, make sure that the graphic is a vector > based image rather than a rasterized version. This will result in a much > crisper looking print reproduction. The process for doing so varies from > program to program, however. > > Best of luck with your project. > > Cheers, > > Rob Oakes >
