[scribus] Colour Management, etc
henryhartley at westat.com
Thu Jun 24 15:40:48 CEST 2010
Jwminer at accessvt dot com wrote
>> Carole wrote:
>> > I know I need to save the pic I want to use as a .tiff so that
>> > when it is resized it will not distort. But, I still am having
>> > difficulty in this area..
>> I'm not sure what you mean by "will not distort." TIFF is a raster
>> format consisting of individual pixels. It WILL distort if resized
>> beyond a narrow range. The graphics that will not distort are those
>> in a vector format such as .svg or .eps (unless it's an eps that
>> includes a raster image).
I suspect what Carole was getting at is that saving in JPEG is a lossy process and so saving in TIFF reduces the loss a bit. If you have a file that is being updated multiple times, multiple lossy saves to JPEG between each update is not a good thing.
My recommendation is to edit the image and save in some lossless format with a bit more flexibility than TIFF. High on the list would be the native .psd of Photoshop, .xcd of GIMP, and .png of Fireworks. Make all changes to that file, which allows you to keep layers for such things as text, shadows, layer masks, etc. When the file is ready for use, crop and scale it to the exact size you want to use at a suitably high pixel density (usually 300dpi). Then save it as either a JPEG with a reasonably high quality, low compression setting or as TIFF. At that point, you'll be hard pressed to tell the difference between JPEG and TIFF. If you're working in CMYK instead of RGB, some of your choices will be different but for "home printing" RGB is what you'll be using.
>> (Dots per inch is meaningless without reference to the actual size
>> the graphic will be printed at.)
Actually, dots per inch is quite meaningful. That's why you often hear it referenced without regard to image size. By itself, it indicates the final image quality (assuming a good image to begin with, of course). Together with pixel dimension, it defines the final image size. It's total dots that is meaningless by itself. That is, saying an image is 900 by 600 pixels is meaningless without knowing if it will be 3x2 or 18x12 inches when printed (or without knowing that it is 300 or 50 dpi). In general, you want to know any two of pixel count, dots per inch, and final print size. For printing, you usually want dots per inch to be at least 150 and generally don't need more than 300.
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