Some of my friends have asked me how I manage to get attractive photographs from my Epson Photo 1200 inkjet printer. After telling the story to several of them, I decided once and for all to write a few notes down.
I take a lot of digital photographs with my Nikon Coolpix 950, and I scan the best of my 35mm photographs with my Polaroid SprintScan 4000 scanner. I play around with the images in Adobe Photoshop 5.0 on my Power Macintosh G3. A year or so ago, I picked the Epson Photo 1200 as the best reasonably-priced photo-quality inkjet printer for my home digital darkroom. The published resolution for this printer is 1440*720 dpi, so I use that as a reference for this document. Any other resolution can be substituted, as well as any other imaging software. And although all of these notes apply to my Macintosh, they should be applicable to other systems, too.
|The number of pixels displayed per unit of printed length in an image, usually measured in pixels per inch (ppi). An image with a high resolution contains more, and therefore smaller, pixels than an image of the same printed dimensions with a low resolution. For example, a 1-inch-by-1-inch image with a resolution of 72 ppi contains a total of 5184 pixels (72 pixels wide x 72 pixels high = 5184). The same 1-inch-by-1-inch image with a resolution of 300 ppi would contain a total of 90,000 pixels.|
Figure 1: Image Size dialog box
An image of the size above wouldn't look very nice printed out because the individual pixels would be clearly visible, resulting in a very "bumpy" image. The goal of this exercise is to figure out how to print images that do look nice printed out.
Figure 1. to the right shows the dialog box that you get when you pull down the Image menu and choose Image Size.... As you can see, the Print Size listed in the dialog box corresponds to the numbers described above in the Screen Resolution section. Now we'll adjust the numbers in this dialog box to optimize our output.
Figure 2: A reasonable resolution value
As you might guess from what you've read so far, we'll need to twiddle with the numbers in the window above to get good printed output. The magic formula depends on following two simple instructions.
Figure 3: Using Size instead of Resolution
In Figure 3, I've entered the traditional 8x10 inch values, and Photoshop has changed the Resolution to 160. In my opinion, this is typically too big for photographs from my Nikon, but again, it's your ink, your paper and your photograph.
Important reminder: Make certain you go into the Page Setup... dialog box and set the orientation of the document to either Portrait or Landscape to match your photograph.
If you have access to higher-resolution photographs, such as the ones that I get from my Polaroid transparency scanner or the images that you get from a PhotoCD, you can have a lot more fun, and of course you'll end up with more data to print. In these cases, you're often able to size photographs up to 8x10 and higher, even at pleasant resolutions such as 360 dpi.
The Last Word
I dearly appreciate the extraordinary effort that has gone into this field, and I salute the brilliant engineers and visionary product people who have designed and brought to market products like the Nikon digital cameras, the Epson photo printers, and Adobe Photoshop. I feel as though, for the first time in my life, I can do something that I can confidently call "art". It's a feeling that I hope many of you are able to feel, too.
Thanks for stopping by.
June 1, 2000
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