This article goes through the process I use to digitally print out my photos to achieve the best quality I know how. You're mileage may vary depending on what you have available to use.
I shoot most of my photos using standard black and white or color slide film. So I need to scan my pictures in. I almost always scan directly from the original negative and at the highest setting, 2400dpi. For 35mm film, this gives an image around 2000x3000 pixels and a roughly 11mb tiff file. Tiff is a lossless format, which means it keeps all data, compared to Jpeg which is a lossy format which creates smaller files but you trade off quality.
If you use a digital camera, you obviously won't have to scan your film. Again, it is best to shoot at the highest setting and save to a lossless (tif or raw) file. Thus giving yourself the most bits to play with.
I save my original scan to an "originals" directory and only manipulate a copy of it, normally stored in a "printable" directory. I perform any color, contrast and all touch up manipulation at the highest resolution.
Now, I resize the image based on what size I want to print the image at. It is very important to print at a DPI your printer likes, otherwise it has to do some interpolation which you will lose quality. The printers tend to like DPIs which are easy factors. For my Epson these are 150dpi, 240dpi and 300dpi, the only three DPIs I'll print at.
You can get photo quality at 150dpi, my preference is for 240dpi and rarely I'll print at 300dpi. I don't think the eye can tell the difference between 240 and 300, and printing higher than 300dpi seems to just be a waste of HP Toner cartridge.
So normally I'll pick the dpi I want to print at and then adjust the image. The following table shows several print sizes for different megapixel and dpi settings.
<div style="padding: 10px" align="center"><table cellpadding="6" cellspacing="0" border="1">
<caption>Image Size to Print Size by DPI</caption>
<thead><tr bgcolor="#CCCCCC"><th>Image Size (megapixel)</th><th>150dpi</th><th>240dpi</th><th>300dpi</th></tr></thead>
<tbody>
<tr><td>3000x2000 (6.0mp)</td><td>20.0" x 13.3" </td><td>12.5" x 8.3"</td><td>10" x 6.7"</td></tr>
<tr><td>2250x1750 (4.0mp)</td><td>15.0" x 11.7" </td><td>9.4" x 7.3"</td><td>7.5" x 5.8"</td></tr>
<tr><td>2000x1500 (3.0mp)</td><td>13.3" x 10.0" </td><td>8.3" x 6.2"</td><td>6.7" x 5.0"</td></tr>
<tr><td>1600x1200 (2.0mp)</td><td>10.7" x 8.0" </td><td>6.7" x 5.0"</td><td>5.3" x 4.0"</td></tr>
</tbody>
</table></div>
An example might help. Say I have a 3000x2000 pixel image from a scan and I want to print an 6x4 image at 240dpi. I would perform any color and contrast manipulations to it at full size. Then using the Resize Tool, I'd change the resolution to 240dpi and then change the print size to 6"x4". The image will automatically be resampled to 1440x960 pixels, which is 240dpi x 6" = 1440 pixels wide and 240 x 4" = 960 pixels height.

The paper you use is also very important. Different types of paper absorb ink differently, there are actually built-in printer drivers for the different papers be sure to select the proper paper setting.
I have an Epson printer and tend to use Epson paper. I've had good luck with their ColorLife Photo Paper (semi-gloss), Premium Luster Photo Paper (semi-gloss), normal Photo Paper (gloss) and their Matte Paper Heavyweight. The matte heavyweight works especially well for black and white.
In the printer setting menu, I normally select printing at 720dpi which is different than the above dpi. The printer dpi is more or less how much ink it will put on the paper. I can't tell the difference between the two settings so normally I pick the lower one to save ink.
<div align="center"><img src="/img/printmenu_screenshot.jpg" alt="printer menu" width="489" height="401" border="1"></div>
That's it (almost). You have everything set. You can now print.
Now if you are really lucky your print will look exactly how you want it. Most likely the print's color and brightness is slightly different than it looks on the screen. I have no magic bullet to solve this.
What you need to do is print out numerous tests and make minor adjustments as you go. If you want to save paper and ink, copy and paste a portion of your image and just print that.
Usually the way I make the adjustments is by fiddling with the color management in the printer driver instead of the photo. My thought is, once I get the printer adjusted just right for a type of paper I can save the setting and use it over again.
<div align="center"><img src="/img/colormenu_screenshot.png" alt="color menu" width="377" height="225" border="1"></div>
Using the above techniques, I have printed a 19"x13" photo from a 35mm slide with excellent results. I hope you have found this mini-tutorial helpful and you achieve better quality prints.
Please send in any tips or ideas you may have.
Here are the following tools I use. The printer and scanner I have are a little on the expensive side. You can get great results with less expensive equipment. The scanner I have allows me to scan large negatives and my printer allows me to print 13" wide. The new ink jet printers for around $100 are very good, most have a maximum print size of 8" wide.
<ul>
<b>Hardware</b><br>
· Scanner: <a href="http://www.amazon.com/exec/obidos/ASIN/B00005OCWM/mkazcom-20">Epson 2450 Photo Scanner</a><br>
· Printer: <a href="http://www.amazon.com/exec/obidos/ASIN/B000059SJ8/mkazcom-20">Epson 1270</a><br>
<br>
<b>Software</b><br>
· Editing: <a href="/photo/tools/photoshop.html">Photoshop Elements.</a><br>
· Scanner: <a href="http://www.hamrick.com/">VueScan</a><br>
</ul></p>
<br/>
<div class="dsection"><div class="title">Related Links: </div>
<ul>
<li><a href="http://www.scantips.com/">Scan Tips</a> - A great site with many in depth articles
about digital photography, scanning and printing. More information regarding DPI and resolution
settings and other digital photography tips.
</li>
<p>
<li><a href="http://www.photo.net/">photo.net</a> - An on-line photography community.
Plenty of information in their archives and very active forums to ask any of your digital
photography questions. You can usually get a good answer or two, just ignore the snobs.</li>
</ul></div><br/>
<div align="center">
<iframe src="http://rcm.amazon.com/e/cm?t=mkazcom-20&o=1&p=13&l=st1&mode=books&search=digital%20photography&fc1=&=1&lc1=<1=&f=ifr&bg1=&f=ifr" marginwidth="0" marginheight="0" width="468" height="60" border="0" frameborder="0" style="border: 1px solid #999;" scrolling="no"></iframe>
</div>