Digital Image Printing 101 

• For each different type of output, a differnt processing is required to fit that output.
• Regardless of size or quality, there are two main printing branches. A continuous tone printing such as a photo finishing print and a digital halftoning print such as a magazine or book.
• What are some considerations?
  1. desired audience
  2. quality expectation
  3. cost
  4. output medium
  5. durability of output
  6. processing complexity

Scenerio 1 

• Here is my recommendation:
  1. You download the images to your computer.
  2. You go into Picasa application and browse through each image and perform some basic adjustments (brightness/contrast, rotate/cropping, sharpening) and export to a folder. By the way, you don't need more than 3 MegaPixels (2000x1500) for this output.
  3. Upload the JPG files to a photo finishing site such as Snapfish.
  Snapfish
  4. Order the prints and quantities (number of copies) and that is it. Your prints will arrive in the mail in about 3-5 days.
  5. This is the cheapest and best for these type of images. It cost 12 cents per print plus some shipping.
  However, if you are in a big hurry, you can always go to your local CVS or Wal-mart and get a print in about 1 hour (19 cents per print).

Scenerio 2 

Some background information... 

• RGB - Color in imaging is represented by RGB (red/green/blue) triplet to create all the various shades of color you see on your display. This is the additive color system where the 3 primary color components add and mix to create all the various shades of color - a possible 16 Million combinations in a 24 bit color system.
  
• CMYK - In printing, color is represented by the subtractive system of inks on paper. CMYK represents cyan, magenta, yellow and black. The key to quality color printing is mapping the RGB input to a CMYK output for printing. This conversion process is sometimes referred to as screening or halftoning.
  
  This is a zoom image of a rosette (detail of most prints).
• Screen angle -
• dot gain -
• dpi -
• color separation -
• halftoning -
• moire -

Some examples of prints... 

Here is a sample monochrome digital print from TIME magazine:

Here is a zoomed view through a 10x magnifier:
(Notice the dots arranged at 45 degrees screen angle)

Here is a color print from TIME magazine:

Here is a zoomed view thru a 10x magnifier:
(noticed the rosette pattern)

Here is an example of a traditional Kodak print:

Here is a 10x zoom view of the above image. Noticed the lack of dots. This is a continuous tone print.

some additional information... 

Society for Imaging Science

Conference papers.

PDF file on Digital Halftoning

From IBM Journal of Research and Development.

halftoning on wikipedia

Digital halftoning.

giclee printing

High quality art reproductions.

Assorted print technologies

A descriptions of various technologies for art prints.

Amazon books 

Selected Papers on Halftone Imaging (Spie Milestone Series, V. Ms 154)

Amazon Price: $118.00 (as of 07/26/2008)

Reader Feedback 

jlazerus Great stuff! Posted May 18, 2007