Basic Image Preparation for Inkjet Printing
May 22, 2013 •
Pro Photo Brooks Institute
Initially we must establish the understanding that any image printed on a sheet of paper can only have highlights as bright as that chosen paper and is limited to shadows as black as the printing machine and said paper are capable of achieving. The white of the paper is easy to see but the black is a moving target, dependent upon the texture and absorbency of the paper and the density of the ink or pigment that is being laid down.
Software such as Adobe Lightroom, Camera Raw or Photoshop have built in numerical scales so that we can watch the tones or shades of our images move to desirable results by focusing on the numbers rather than the image on screen.
For example, Lightroom uses a scale of 0% through 100% representing black (most ink) through white (paper, no ink). Photoshop’s scale is reversed, having 0% represent white through 100% black (0 through 255 black to white if you are reading RGB). Both have info panels that display these numbers so that, by using the different slider and curves tools, we can place the cursor in an area and control image densities and colors by numerical representation.
It is recommended to begin your preparation workflow by determining the important whitest (highlights) and blackest (shadows) points in the image. You can do this by holding down the option key on a Mac (alt for PC) and in Lightroom sliding the exposure slider for the highlights and the blacks slider for the shadows. In Photoshop you use the levels or tonal curve, sliding the end points into the histogram with the option or alt key held down.
Once you have determined your highlight areas that you decide need to be bright but still hold some image detail, set the density of that area around 95% in Lightroom or 248 in the RGB scale of Photoshop or Camera Raw. The shadows needing detail to show will need to be about 7% or higher in Lightroom and 12 or higher in Photoshop or Camera Raw.
After these important highlight and shadow numbers are set, you can adjust the mid tone contrast, density, hue, and saturation levels to your aesthetic taste. Your print will be as bright and white in the details as the paper you chose and the shadows will be rich and dark.