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Digital-Halftone Intaglio-Type


by Donna Adams


An aquatint screen exposure prior to an image exposure with a photo stencil produces a continuous-tone non-etch intaglio-type monotone print. To avoid the necessity of an aquatint exposure, manipulate the photo stencil in Photoshop to create a digital halftone for a non-etch intaglio-type monotone print. Before manipulating the photo, determine the density for the transparency and inkjet printer that opens up 100% blacks to an 80% random dot structure by making the Dot Structure Density Test.

Manipulate the Image in Photoshop

Materials and equipment
Manipulating the image requires: film or digital photograph; Photoshop (or other image-manipulation software); transparency, such as Azon 787N Clear Graphic Film; and an inkjet printer, such as Epson PRO 7600.

Steps

  • Open the original photo file and save as a new tiff file in a new folder to preserve the original file. Work only with the duplicate file.
  • Change the size to fit the transparency: Image, Image Size, uncheck Resample Image, as in the top right figure. Fill in the inches. Click OK.
  • Change the resolution so it is at least 1/4th the printer output, 720 on the Epson PRO 7600 (some say 1/6th or 120): Image, Image Size. Check Resample Image, Bicubic, and Constrain Proportions, as in the second figure, right. Change the resolution in steps, as 111.889 to 150 dpi and then 180 dpi. Save as a new file.
  • Crop the image if it improves the image or if needed to fit the transparency: Select with a Marquee Tool; then Image, Crop.
  • Straighten any angled lines: Select, All; Edit, Transform, Skew.
  • Straighten the image if needed: Image, Rotate, Arbitrary, and then fill in degrees and CW or CCW.
  • Change the Mode to black-and-white: Image, Mode, Grayscale. Save as a new tiff file.
  • Improve the contrast: Image, Adjustments, Levels. Move the sliders as needed to get black and white. In the bottom figure, the black slider below the histogram would be moved to the right. Save as a new tiff file.
  • Magnify the image with the Zoom Tool in the Toolbox to remove defects with the Clone Tool or Band-aid Tool. Save as a new tiff file.

  • If the image was scanned, sharpen the image in increments; do not sharpen digital camera images. To sharpen: Filter, Sharpen, Unsharp Mask, check Preview so you can see the effect. Use 25-50%, 1-3 Radius, 0-2 Threshold, as shown in the figure opposite. Save as a new tiff file. If needed, repeat these steps and save as another new tiff file and add "fixed" to the title.
  • Use the Zoom Tool to return the image to a size that fits the screen.



Prepare the Digital-Halftone Stencil

After performing the dot structure density test for the printer and transparency and determining the percentage with the blackest black, the image will need to be adjusted accordingly.

Steps
  • The easiest way to lower the density of blacks is in Curves: Image, Adjustments, Curves; then drag the black diagonal to the percentage determined by the dot structure density test. In the second figure, right, the diagonal was moved to 80% since the best black printed at 80% for Azon 787N Clear Graphic Film in an Epson PRO 7600 Printer. In my experience, the light tones drop out also, so the diagonal is also moved to 15% to leave some dots in the whitest whites.
  • Save the file with the title "ready".
  • Set the printer to best quality, Black. If the printer has the option, print with two cartridges of matte black ink. To print AZON 787N Clear Graphic Film in the Epson PRO 7600 Inkjet Printer: Select the printer and film size; in Print Settings, select Black, Adhesive Vinyl, Advanced (uncheck all boxes), 720 dpi.
  • Print on the emulsion side of the transparency. Be careful handling the transparency to avoid fingerprints that could block light.

The digital-halftone transparency is now ready to be used in the standard manner for image exposure without an aquatint screen exposure to produce a monotone image.





Example

The example used throughout this topic began with a scan of a small portrait taken in the early 1900s (top left).

The photo was manipulated in Photoshop to enhance it, as described in this topic (bottom left).

To enhance the aged effect, the photo was cropped to an oval.

Finally, the photo was adjusted in Curves to prepare it for printing onto Azon 787N Clear Graphic Film with an Epson PRO 7600 inkjet printer (immediate left).

Note that the contrast is reduced when Curves are changed to 80% and 15%.

Digital-Halftone Intaglio-Type

Monotone Photo Intaglio-Type is a non-etch technique for producing photographic quality continuous-tone imagery without the necessity of an aquatint screen exposure. If blacks in the photo stencil are denser than 80% random dot structure, the blacks drop out in the developed ImagOn plate and produce whites in the print. Aquatinting in traditional etching or an aquatint screen exposure in non-etch intaglio-type break up the solid areas, which avoids open biting.
Photographs can be manipulated in Photoshop (or other image-manipulation software) to open solid blacks to 80%. Inkjet printers produce a random dot structure. These two qualities permit image exposures without the necessity of an aquatint screen exposure.
The easiest way to determine the necessary Photoshop manipulations for digital halftone photo stencils is to make a dot structure step-test for the transparency and printer. The step-test needs to be performed once to determine the best density of black for each transparency and printer combination. 

Dot Structure Density Test

Materials and equipment
The step-test requires: Photoshop (or other image-manipulation software); the transparency that will be used for the photo stencil, such as Azon 787N clear graphic film; the inkjet printer that will be used for the photo stencil - it should be able to print opaque blacks without mixing black with colored inks, such as the Epson 7600 or Epson 3000; loupes OR laminated ImagOn plate and standard developing, inking and printing materials and equipment

Steps for the making the step-test transparency

  • In Photoshop, make a new file and name it density test: File, New
  • This brings up the menu shown in the figure top right. Name the file and complete the options as shown in the menu. The dimensions shown here assume a transparency size 8½ x 11 inches.
  • Make sure the foreground and background colors at the bottom of the Toolbox are the default: black foreground and white background.
  • In the Command Menu, click on Select. This brings up a drop-down Menu; click All.
  • Select the Gradient Tool in the Toolbox and the Linear Gradient in the Options Bar. Draw a straight line from the top to the bottom. This produces the gradient shown in the figure opposite.


  • In the Command Menu, select Image. This brings up a drop-down Menu; select Posterize, which brings up a pop-up menu. Change the Levels to 21. This produces the distinct gradients shown in the figure opposite.
  • In the Command Bar, choose Select. This brings up a drop-down menu; click on Deselect.
  • In the Toolbox, select Text.
  • Label each distinct gradient, from 100% at the top bar to 0% at the bottom bar. The file should now look like the second figure. Note that the text is in white for the dark tones and black for the light tones to facilitate easy reading.
  • Save the file.

  • Print the dot structure density test on the emulsion side of the transparency with the inkjet printer you plan to use for photo stencils. Set the printer to best quality, Black. If the printer has the option, print with two cartridges of matte black ink. To print AZON 787N Clear Graphic Film in the Epson PRO 7600 Inkjet Printer: Select the printer and film size; in Print Settings, select Black, Adhesive Vinyl, Advanced (uncheck all boxes), 720 dpi.
Option 1:
  • Examine the transparency with loupes to determine where the dot structure is 80% random black dots (bottom photo).
  • When manipulating photos in Photoshop, plan to move either the Levels or Curves to change 100% black to the percentage that produces the 80% random black dots; OR
Option 2:
  • Position the transparency on the laminated ImagOn plate emulsion-to-emulsion at the platemaker.
  • Expose the transparency with the light units required for the standard aquatint screen exposure.
  • Develop and print the plate.
  • Examine the print for the blackest black; this could be anywhere from 85% to 55%. The blackest black is the 80% random dot structure. In Photoshop, move either the Levels or Curves to change 100% black to the percentage that produces the blackest black for the transparency and printer combination.

Digital-Halftone Intaglio-Type 


for Monotone Photo Stencils



An aquatint screen exposure prior to an image exposure with a photo stencil produces a continuous-tone non-etch intaglio-type monotone print. To avoid the necessity of an aquatint exposure, manipulate the photo stencil in Photoshop to create a digital halftone for a non-etch intaglio-type monotone print. Before manipulating the photo, determine the density for the transparency and inkjet printer that opens up 100% blacks to an 80% random dot structure by making the Dot Structure Density Test.

Manipulate the Image in Photoshop

Materials and equipment
Manipulating the image requires: film or digital photograph; Photoshop (or other image-manipulation software); transparency, such as Azon 787N Clear Graphic Film; and an inkjet printer, such as Epson PRO 7600.

Steps

  • Open the original photo file and save as a new tiff file in a new folder to preserve the original file. Work only with the duplicate file.
  • Change the size to fit the transparency: Image, Image Size, uncheck Resample Image, as in the top right figure. Fill in the inches. Click OK.
  • Change the resolution so it is at least 1/4th the printer output, 720 on the Epson PRO 7600 (some say 1/6th or 120): Image, Image Size. Check Resample Image, Bicubic, and Constrain Proportions, as in the second figure, right. Change the resolution in steps, as 111.889 to 150 dpi and then 180 dpi. Save as a new file.
  • Crop the image if it improves the image or if needed to fit the transparency: Select with a Marquee Tool; then Image, Crop.
  • Straighten any angled lines: Select, All; Edit, Transform, Skew.
  • Straighten the image if needed: Image, Rotate, Arbitrary, and then fill in degrees and CW or CCW.
  • Change the Mode to black-and-white: Image, Mode, Grayscale. Save as a new tiff file.
  • Improve the contrast: Image, Adjustments, Levels. Move the sliders as needed to get black and white. In the bottom figure, the black slider below the histogram would be moved to the right. Save as a new tiff file.
  • Magnify the image with the Zoom Tool in the Toolbox to remove defects with the Clone Tool or Band-aid Tool. Save as a new tiff file.

  • If the image was scanned, sharpen the image in increments; do not sharpen digital camera images. To sharpen: Filter, Sharpen, Unsharp Mask, check Preview so you can see the effect. Use 25-50%, 1-3 Radius, 0-2 Threshold, as shown in the figure opposite. Save as a new tiff file. If needed, repeat these steps and save as another new tiff file and add "fixed" to the title.
  • Use the Zoom Tool to return the image to a size that fits the screen.



Prepare the Digital-Halftone Stencil

After performing the dot structure density test for the printer and transparency and determining the percentage with the blackest black, the image will need to be adjusted accordingly.

Steps
  • The easiest way to lower the density of blacks is in Curves: Image, Adjustments, Curves; then drag the black diagonal to the percentage determined by the dot structure density test. In the second figure, right, the diagonal was moved to 80% since the best black printed at 80% for Azon 787N Clear Graphic Film in an Epson PRO 7600 Printer. In my experience, the light tones drop out also, so the diagonal is also moved to 15% to leave some dots in the whitest whites.
  • Save the file with the title "ready".
  • Set the printer to best quality, Black. If the printer has the option, print with two cartridges of matte black ink. To print AZON 787N Clear Graphic Film in the Epson PRO 7600 Inkjet Printer: Select the printer and film size; in Print Settings, select Black, Adhesive Vinyl, Advanced (uncheck all boxes), 720 dpi.
  • Print on the emulsion side of the transparency. Be careful handling the transparency to avoid fingerprints that could block light.

The digital-halftone transparency is now ready to be used in the standard manner for image exposure without an aquatint screen exposure to produce a monotone image.





Example

The example used throughout this topic began with a scan of a small portrait taken in the early 1900s (top left).

The photo was manipulated in Photoshop to enhance it, as described in this topic (bottom left).

To enhance the aged effect, the photo was cropped to an oval.

Finally, the photo was adjusted in Curves to prepare it for printing onto Azon 787N Clear Graphic Film with an Epson PRO 7600 inkjet printer (immediate left).

Note that the contrast is reduced when Curves are changed to 80% and 15%.