I would also like to comment on the concept of increased density range of a digital negative. There is more than one means of attaining increased density of a negative, being the work is produced digitally through software such as Photoshop, Lightroom, or Corel Paintshop Photo Pro, which I use instead of Photoshop. I will be using the 'Curves' method here, being it is the method that Dan Burkholder and Peter Mrhar deal with it in their writings. Just know there are others avenues.
When you bring up the 'Curves' function, it begins as a straight line, representing the Contrast Index curve as seen on any D Log E curve, which represents the increased density range of a negative from the thinnest (Zone I) at the "toe" of the curve, all the way to the "shoulder" of the curve, which represents (Zone VIII). I still use the Roman numeral version.... To increase the densities of the middle tones, the line is moved 'up' from the straight line portion. To do this, place the cursor on the line just above the lowest point of the line, and again near the top of the line, equidistant as the bottom one. Then by pulling the line up in the middle, you will see the line bulging up as you pull it upwards. Not the best explanation for this maneuver, but if you use Photoshop or Paintshop you will grasp what I'm saying.
Diagram of the Contrast Index Curves; increasing densities by moving the CI curve upward;
Top chart represents Dan Burkholder's method of increasing the density range. Bottom chart represents the method I am currently applying for increased density range.
Notice the base lines of the two Contrast Index Curves. The top one represents the curve of the positive image as scanned, or represented digitally from the original image. As per Dan Burkholder, the dotted line is the result of the increased densities by move the cure into that position. Also notice that what remains in the original position is the top density; Zone 8. That doesn't get moved with the rest of the densities. To compensate for that lower density, compared to the rest of the increased densities along the line, he utilizes "spectral" density, using the color green, applied to a adjustment 'color' layer to tint the image after the curve density increase, and then reversing the image to a negative.
The primary problem with printing digital negatives has been reaching sufficient ink density to block light sufficiently to retain white in the print. Of all the colors, green is the one that blocks light the best. More on that later. The reason for two charts is simply to compare Burkholder's methodology to my own original approach to the process. Top Chart represents Burkholder's method. The lower chart represents a bit different approach. When comparing the two, although they look pretty similar, notice the lower curve line is more vertical. The more vertical the contrast index line, the more contrasty the negative image.
Burkholder's curve line has greatly increased middle tones, but to also increase the top tonal ranges, representing the whites in the image, he then applies the green color to the negative to retard the UV light which then increases contrast sufficiently to keep the whites from printing in too early. The lower contrast index line is actually more contrasty to begin with, and the top densities representing the whites; Zone 7 & Zone 8, which have also been increased proportionally with the rest of the densities. I accomplished this somewhat in reverse of Burkholder's procedure.
First thing I did was reverse the image to it's negative form. In Lightroom, I used the four control slides for the image; *Highlights, Shadows, Whites, Black. I go the the shadows first as that will control the densities in Zone 3, shadow detail, then the Black slide to separate the densities below Zone 3 for a deep black (reducing the densities therein), then go to the Highlights & Whites, which represents the upper densities and pure whites, and make those densities good and black. This method is the "inspection" method. There is nothing mathematically sound or analytically correct about this method, just intuitive body knowing sort of work.
What I am finding is that the 'truism' that one cannot reach sufficient density in a digital negative to print in silver or platinum/palladium without using spectral density is not completely true. The method used by Burkholder works, well. He's been doing this for twenty years. However, one can go around this by my method as well, with the advantage of not needing said spectral density by applying green color on an adjustment layer. The tests I'm conducting now have demonstrated that I have exceeded the density range needed for a good hand coated silver print. Dan's method does not move the density of the top tonal ranges; Zone 7 & Zone 8. My method moves the entire curve upward, proportionally to all densities.
I will of course be revisiting this subject often as I progress with the testing until I arrive at a negative method that prints as intended. The image below represents where I am headed, with printing in silver using digital negatives. A full range of tonal values, with texture and detail, as well as a good black. When I arrive at this goal you will be the first to see the results.
Salted Silver Print ~ (Salt Paper Print) "The Orchard"
1986 ~ 5x7 Unique
Eugene, Oregon
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