Thanks, Rob. That was very clear and helpful! Richard
On Mon, 2010-01-25 at 13:12 -0700, Rob Oakes wrote: > Hi Richard, > > << Can I ask a quick supplementary? >> > > Of course. > > << The jpgs are at the 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? >> > > By all means, process the files. If possible, do this yourself or have > someone with a good photographic eye do it. This ensures that you get the > image that you want. If you don't convert them, then someone (or worse, > some machine) at the printers will. This can sometimes result in a final > product different than you had envisioned. > > Black and white is a completely different medium than color and it usually > takes a little bit of tweaking to make sure that you get the images to your > satisfaction. For example, most black and white photos should have a bit > more contrast and a slightly higher adjusted exposure than the equivalent > color photograph. This helps to bring out relevant details that might > otherwise not be visible. (Keep in mind that I tend to be extremely fussy > about images and figures.) > > The conversion shouldn't really cost you any definition, since you're only > converting from color to black and white. Loss of "definition" seems to > happen when changing the physical dimensions of the image. The conversion > can be done in the photo program of your choice, but using Photoshop or Gimp > will give you a tremendous amount of fine control over the image appearance. > > Re: JPEG to Tiff conversion. If your source images are already JPEG, then > you shouldn't you don't really gain anything by saving it to TIFF (though I > would anyway). If you save back to JPEG, make sure that the "quality" bar > is set to 100%, or it will further compress the image and you will lose > additional data. > > Also, when you "scale the images", make sure that they aren't down sampled > (some image editing programs don't distinguish between the pixel dimensions > and the physical dimensions). You want the pixel dimensions to remain the > same, regardless of the physical dimensions. Most printing presses require > images that are at least 300 dpi, though bigger is *always* better. It's a > completely different mindset than when creating something for online > distribution. > > Thus, I would avoid Photoshop's "Save for Web and Devices" feature or > anything any-way similar. The entire purpose of "Save for Web and Devices" > and co. is to down sample, not scale. > > One final thought: as long as the source images are of sufficient size, I > would stick to scaling inside of LyX itself. There is a dialog box that > will let you specify the physical dimensions without messing with the source > image. > > Hope this is of some help. If you have any other questions, please don't > hesitate to let me know. > > Cheers, > > Rob >
