Yeah, that's a bad bug. Seems to me that it occurs on /any/ reduction including one done with the filters posted on this thread. This is trashing people's data from what I can tell.
On the url you mention, I was going to see if that was the next piece of info for me to tackle but I think I am just using these filters (which I already have loaded) and I will just watch out for the CMYK issue.
Is there a way for me to know - hopefully visually - whether a pdf is CMYK? I mean, you pretty much have to go out of your way to print (is it about the printing or I guess it is really about the images) or have a pdf that is CMYK? Is it pretty much very professional looking docs that are basically going to print?
Also, the url - forgive the newbie here - it is showing me how to assign a image reductions scheme for images and then I assign this scheme to Preview by dragging - or I guess it is automatically added to Preview somehow /within/ the OS? I mean - can I just bother you long enough to /explain/ how color sync works in Mac OS again? Like mechanically how it gets linked up to whatever it links up to and what it does and why? I am sort of fumbling between color sync and automator and preview and it is all a bit much for the new guy not used to having to interact with this aspect of the OS...
Thanks a *TON* again.
Is there a way for me to know - hopefully visually - whether a pdf is CMYK?
There doesn't appear to be. I opened a small TIFF in Preview, which when you press Command+I for the info dialogue, it displays that it's an 8 bit, RGB image, 300 dpi. But as soon as you make it a PDF, all of that information disappears. You have no idea if it's RGB, CMYK, what resolution or anything. And it's not just Preview. Adobe Acrobat Pro or the free Reader don't tell you, either.
Any compressed CMYK conversion to PDF through Preview is thoroughly botched. It isn't just inverted, but the channels get heavily posterized and mixed around in a seemingly random fashion. Very much destroyed.
can I just bother you long enough to /explain/ how color sync works in Mac OS again?
ColorSync's job is to convert color between one object and the next so color appears as consistently as possible. For instance, the colors of an RGB image to a printer. Since printers use CMYK inks (and usually a couple of extra richer colors to boost reds and blues), ColorSync does its best to convert what you see on screen (the monitor profile) to the printer's profile (its color space which it is able to reproduce).
It's really weird that Apple stuck some of these functions into the ColorSync Utility since scaling images, creating PDFs and such have nothing to do with ColorSync. It's no wonder very few people have ever run across these things. I'd never seen it until following a link to the web page I linked you to.
All in all, it's still extremely limited. Heck, Apple's own sample choice "Reduce File Size", doesn't even work. It's supposed to reduce the image by 50% and then apply JPEG compression. Say you apply it to a raster image that's 1000 pixels wide by 500 pixels tall. You would expect the resulting PDF to be 500 x 250 pixels. It isn't. Opening the PDF in Photoshop, it's still 1000 x 500, so it hasn't been scaled at all.