The settings that you use when you create your pdf can really affect the quality of your photos. Remember that grayscale images have their own quality setting.
Thank you for the response. I didn't know grayscale images had their own settings and at this point would be clueless as to what they are. I'm using Acrobat Distiller 3.0 which may be old and doesn't see to give a lot of setting options. If you want to pursue the discussion, what controls the settings, InDesign (which I'm in the process of converting to) or Distiller?
(I'm probably so clueless because most of my work is just basic text and grayscale graphics - nothing fancy.)
The best thing to do is talk to your outside printer about the pdf settings, they may have some settings prepared for you.
For Pagemaker, Distiller controls the settings, Indesign can export pdfs directly.
In Distiller under settings/Job options there should be a tab called compression (my names may be off, It's been a while) there should be settings for color, grayscale and monochrome bitmap images, the general rule of thumb for offset printers is to set the color images to 300 dpi and to set the compression to zip or jpg with the highest quality, bitmap at 1200 dpi and CCIT group four compression.
Indesign is basically the same but you can export to pdf directly and have control over the compression settings within indesign, It also has some preset settings already created, in a pinch pdf X1a settings are a good default.
Be prepared for large pdf sizes, yours won't be too bad without any color images, but I have seen too many people try to shrink their pdfs down to tiny sizes to make them easy to email.