DISC Quality Categories

DISC Categories

The DISC Working Group developed a “Category Table” as a tool for publishers to communicate requirements to photographers. This table defines categories for the digital images submitted to a publication. Each category is based on the dots per inch, dpi, of the printed image. Publishers will use this table to select the image quality category that work best for their publication and use this category designation when communicating requirements to photographers.

The 3 DISC categories are:

	Category A = 300 dpi (or 150 line screen for halftone screening)
	Category B = 250 dpi (or 125 line screen for halftone screening)
	Category C = 200 dpi (or 100 line screen for halftone screening)

A specific dpi range is recommended by publishers based on the paper stock being used or the quality of the publication. DISC categories are roughly equivalent to monthly (commercial), weekly (publication), and daily (news) publications with the corresponding grades of paper stock. Category A is the highest print quality and Category C is the lowest.

Note: Photographers speak of images in pixels per inch or ppi. The pixels of a digital image are converted to dots when the image is printed. The number of pixels per inch in an image has a 1-to-1 relationship to the number of dots per inch in the printed image.

Since DISC was first developed in 2003, digital photography has seen significant technological advances. These advances have lead to a redesign for the DISC Categories and recommendations. For example because digital cameras are so much more powerful today, DISC 2.0 evaluates image resolution in megapixels (1,000,000 pixels or MP) rather in pixels. Camera megapixel ratings used to be technically calculated as a ratio of 1024. Today camera megapixel ratings are commonly calculated as a ratio of 1000. So DISC camera megapixel ratings are now calculated using the modern 1000 ratio.