Monday, June 7, 2010

The Process - Making a Digital Negative

In a regular darkroom, you would take the analog negative (say a 3.25" x 3.25" as would be produced by a Rolliflex) and enlarge it using an optical enlarger. But with a digital camera, you have no negative to enlarge. And so you make one precisely the correct size. With a medium format printer, it is possible make a 16" x 20" negative at high resolution. This in turn makes it possible to directly print a positive image from the same-size negative. The enlargement occurs in Photoshop rather than the enlarger.

Many express surprise that it is possible to make digital negative on a regular printer. In fact, anytime someone prepares an overhead transparency for a presentation (or any other reason) has gone through the same steps as in printing a digital negative. One starts with a transparent printing media such as Pictorico's or Digital Art Supplies Transfilm. One side of the material is prepared to accept quite an amount of ink. The best digital negatives are produced with high-resolution printers. Mine is an Epson Stylus Pro 4000 which can print at 2800 dpi. It turns out to be possible to print high-resolution digital negatives from files whose resolution varies from 180 to 240 dpi. The most important factors are proper exposure and good focus such as is possible on a bright day. So one is putting the finishing touches on a favorite image in Photoshop (or GIMP or any of a number of such programs). The image is still in color. All factors are "Go". The image is well-cropped, balanced, straight (or intentionally askew), and so on. It is appropriately sized (say 11 x 14 or 16 x 20). The appropriate color profile and color depth are assigned to the file. Any new metadata is assigned to the file (such as the title, caption, author). Now you are ready for two quick steps:
  • Converting the image to black-and-white and then
  • Inverting and rotating the image (so that it is a true "negative")

Now you are ready to print.

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