Solving the Problem of the Digital Negative
Don’t waste your time trying to fix incorrectly inverted negatives
A whole mythology has developed around how to fix the incorrectly inverted “negative” produced by the editing software. This mythology has become so entrenched that it has persisted unchallenged, without examining the source of the problem or considering if there is a better approach, until TruNeg.
The True Solution to Making Digital Negatives
The solution lies in the inverse proportion between the positive and negative logarithms, making it possible to calculate true digital negatives from only two inputs and a single test strip, eliminating the need for densitometers, scanners, linearization procedures, etc.
Logarithmic negatives embody the full tonal range, from the deepest shadows to the brightest highlights, and they make prints indistinguishable from, or better than, those made with silver gelatin negatives. Better than, because the negative can be modified by profiles to compensate for the low contrast in the highlights and shadows.
Copy of Carbon Print (Oxide Black) made with a TruNeg Negative
The TruNeg Logarithmic Curve Window
At the centre of the application is the interactive 16-bit plot of the negative and positive RGB logarithms. The plot shows the calculated negative in blue and the profiled negative in yellow. The negative can be amended by clicking the mouse on the plot to specify new control points and modify the negative to lighten or darken selected zones in the print.
As noted above, photographic materials do not respond consistently to exposure, resulting in washed-out highlights and blocked shadows unless corrected in the negative, Classic Cyanotype highlights being the most extreme example. TruNeg has tested and developed profiles that adjust the negative for Argyrotype, Classic Cyanotype, Carbon/Gum Bichromate (A. Dichromate), Salt and Van Dyke Brown.
Download and print the Calibration Negative and find the minimum exposure that produces a clean white and maximum density when printed on the selected process.
Open the Calibration menu and enter the two RGB values that produce ”just white’ and ‘just black” from the calibration print, load the profile and save the preset.
In the Convert Menu, open a test strip of the image, select the preset and press OK to convert to negative.
Print the negative, print and check the test strip.
Correct any unsatisfactory tones in the Curve window and reprint the test strip with the new preset.
When happy, print the print.
Full Instructions are Available in the Main Menu.
Using the Application
Summary
Starting with an authentic photographic negative, the TruNeg application provides a straightforward pathway using traditional test strips to create prints that can meet the needs of the most demanding user.
To Make a Print:
Making a Print with the Salt Process.