So, if I import the JPEG into photoshop at its current size of 25x25 (72 DPI) and change the resultion to 300 and the size to 5x5, then I won't have a problem with image quality when going to print (offset)?
For those interested, the following is an easy formula for determining photo resize dimensions. The information above regarding the de-selection of the "resample image" box in Photoshop is by far easier, but there are times when understanding how images are resized is important
1) Determine the line screen (lpi) of your final printed output. (Generally this is the line screen used by your service provider when outputting press plates.) Multiply that by (2). This is your target resolution.
2) Divide your target resolution by the resolution (ppi) of the native file. This is offset ratio.
3) Take the native file and divide any side (in inches) by the offset ratio.
The result is the maximum size of the photo on that side without image interpolation at your target resolution.
Example One: You have a camera photo sized at 29.667 inches x 39.556 inches at 72 ppi. In our example, we are preparing a photo for offset printing. Our service provider outputs their plates at 133 lines per inch. We multiply this figure by two and have 266 ppi as our target resolution. We then divide our target resolution by our native file format resolution. 266ppi divided by 72ppi returns an offset ration of 3.694. We can then divide our native photo dimensions by this ratio and this will give us the maximum size of the photo:
8.03 inches x 10.70 inches
Something that should be mentioned for versions 7 and 8 of Photoshop is the Auto Dialog that is found in the Image Size Dialog. This dialog performs step one in our process automatically and has three presets: Draft, Good and Best.
Depending on your output device, Best is the highest quality and generally used for printed items. It is recommended that you use Good for anything printed which is larger than a tabloid sheet (11x17) Generally, pushing the resolution beyond this setting will result in longer pre-press processing with no visible increase in quality.
Hope this has been helpful.
Current equipment includes a Nikon D80 and a Fuji F10.
Kandiekay the easiest way is to determine the size to download, is to first ascertain how much resolution you need for your output. If I am designing for a website, I only need 72 dpi, wherease most print applications need 300. What this means is that if you broke the image down to just the number of pixels that create the image, you need 72 pixels to make up an inch of image on screen, but need almost 4x that much to print the same image without image loss (300 pixels in a inch). So the size and resolution are going to be greatly dependent on what you are planning to do. Many applications require different resolutions, and it is best to strictly adhere to those for best results..
A quick rule of thumb regarding resolution is that you can always lower the resolution and throw image data away if you dont need it, but once gone it can never be made larger again. This means that you never shrink your backed up image, and if you download something too small to begin with, you cant increase its size.
The best thing to do is what Mark suggested above
write your text hereJust use 'Image Size' in photoshop (menu: Edit):
- mark 'Constrain Proportions',
- unmark 'Resample Image',
- fill in your preferred Width or Height
and see what Resolution does. For Press 300 dpi or more is perfect!.