It is possible to use a computer to adjust or modify photographs in ways that are either very difficult or not even possible in a darkroom. The digitally adjusted / constructed images are printed onto a special white frosted inkjet film that can be contact printed onto regular silver paper and processed in a darkroom. All of the usual darkroom printing techniques can then be used to take the piece further than can happen in the digital domain.

This recipe details how to make digital negatives in a few simple steps.

scan your negatives [or start with a digital photo, converted to greyscale]
• properly adjust the photo BEFORE you apply the DigiNeg alterations!
       • layer sharpen
       • adjust the levels
       • apply a contrast curve
add a step wedge (optional)
flip horizontal
invert to negative
apply output levels adjustments for the specific paper
add some texture (optional)
print the picture onto white transparency film with these settings
apply these settings to other photos

  Use an Epson v700 or other scanner  
import the source image into the computer
  see the "Scanning" tutorial for more details
  or start with a digital photograph
open the file in Photoshop
  convert the color space to Adobe(RGB) 1998
  set the image size resolution to 300 ppi

to appropriate picture size in inches

SAVE AS… immediately with another name
open Photoshop
open a scanned negative file     
            FILE>OPEN...       [CMD] O
resize to the exact size of the final print
  the size of the digital negative has to be the same size
as the final print because it will be a contact print
straighten the photo using the ruler tool
  use the ruler tool along the long edge
  use the rotate option (automatically set by the ruler tool)
convert any color images into greyscale
  use the Channel Mixer
see the "Greyscale Conversion" pages for detailed recipes
sharpen using layer sharpen
  see the "Layer Sharpen" tutorial for more details
adjust the tonality to the desired appearance
  set levels

with an adjustment layer

    adjust the endpoints to remove any empty tonal space
  set curves

with an adjustment layer

    add more contrast to give it 'pop'
INCLUDE a STEPWEDGE (optional)      

Expand the Canvas and drag a Step Wedge picture file into your picture to use as a test strip when printing.
This has to be under all the adjustment layers that are about to be applied for it to be useful.

open the Step Wedge file
  the file is in Zip format, so it has to be 'un-zipped'
  rotate or resize to the image size, if necessary
select the Background layer
drag the Step Wedge into your picture
  it will come in on a separate layer
  make sure it is just above the Background layer
move the Step Wedge off to the side

note: the Step Wedge can be trimmed off and used with a separate piece of paper.

FLIP the PICTURE      
  because the negative is turned face down to print emulsion to emulsion.  
flip horizontal using     image> rotate> flip horizontal
  to make the picture into a negative.
use an Adjustment Layer so it can be turned off to double-check you picture later.
add an adjustment layer> invert

The goal is to print a digital negative that has the right density and tonal range.
Applying this adjustment curve will render the image flat and will look terrible.
This is exactly what is needed for the tonal range of silver gelatin photo paper.

This curve produces a reduced tonal range for silver emulsion.
This must be the topmost layers in the stack
     because the layer will alter the density of the picture
     to make a properly exposed print.

add a new Adjustment Layer> Curves

the layer Silver Adjustment

set the output levels to new lower values
  silver : (endpoint values = 15% ~ 85%)
    set the shadow output value to 38
    set the highlight output value to 217

The contrast now needs to be raised to make up for the reduced contrast of the liquid emulsions.

lock the midtone value
  by placing a control point dead center 3 crosshairs down
    output = 179, input = 128
raise the highlight intensity
  by adding a 2 control points downward, as shown
lower the shadow intensity
  by adding a 3 control points upward, as shown

These values may have to be adjusted differently for each individual picture!
ADD some TEXTURE (optional)      
  Traditional negatives for contact printing are made on Litho film that is inherently grainy.  
select the background layer
use Filter> Noise> Add Noise…  
  8 ~ 12% or as you prefer
or Filter> Texture> Grain…
  1 ~ 20 or as you prefer

note: filters cannot be undone like adjustment layers

  onto professional-grade White Transparency Film.  
use only a high-quality White Gloss Inkjet Film
  PictoRico Pro Hi-Gloss White Inkjet Film
     20 sheets of 8.5 x 11" costs $34.00, or -
InkPress White Gloss Inkjet Film
     20 sheets of 8.5 x 11" costs $29.29
print onto the textured side of the transparent film
  place the cut corner into the upper right corner (PictoRico only)
rotate the page in Page Setup (if necessary)

to print vertical picture on a vertical page,
or a horizontal picture on a horizontal page

PRINTER SETTINGS for Digital Negatives    
  Print on a Canon ipf5100 / 6100 / 6300 printer using Gloss Ink.  
  set the front panel controls first:
feed: sheet (not roll)
media type: Backlit Film
media size: Letter/ 8.5"x11" (or whatever size you are using)
  hit [ok] to load film
  status window will read:
  Offline, Loading…
  the film will be drawn into the printer and loaded
  wait for the status to read Online Letter
continue to the Export dialog box, explained in the next section
if you have access to another inkjet printer, that can be used as well
  then set the Print Dialog Box specs in the Export Plug-in window:    
open the Export Plug-in for the Canon printers
  use file> export> iPF5100 Print Plug-in…
select Main tab
  media type : Backlit Film
  resolution: High Accuracy 600ppi
  image bit to plug-in: High Gradation 8 bit
  print mode: High (High Precision)
  output profile: Canon Backlit Film
  matching method: Perceptual
select Page Setup tab
  set : Enlarged/ Reduced Printing
  scaling: 100%
    it is possible to rescale the print size here
    but DO NOT enlarge more than 10%
          (Photoshop does a better job)
  media size : Letter (8.5 x 11")
  orientation: Portrait or Landscape, as required
  layout: Center of Output Media Size
    position can be altered by dragging the image in the box
  media source : Manual
hit: [print] to proceed
    or [return] key or [enter] key
  if you have access to another inkjet printer, that can be used as well

Simply select ALL Adjustment layers and DRAG them to any other picture file.
You will most likely have to readjust the Channel Mixer to get the best B&W Conversion,
        but all the other alterations are the same! This is even easier than creating an Action.

unstack the photographs to be used
select all adjustment layers in the finished photo
drag all layers to the other photograph
turn on / off whichever layers will display the desired effect
readjust the Channel Mixer to get the best B&W photo first