Digital Light & Color

Does anyone have any experience in making digital negatives for use in Platinum and Palladium printing? i am not ure how to translate the Photoshop information available into a PWP workflow.

I do not have expierience in Platinum printing, but the PS curve files (*.acv) are quiet easy to translate to PWP curve files.
For example i took the 2400-K3mk-Gloss-Ag.acv file from here:
http://www.digital-negatives.com/index_E2400.htm

All you need is a program to read the file in HEX mode and a calculator to convert Hexadecimal values to decimal (the windows calculator is just fine).
As a HEX Reader / Editor i use the free PSPad.

The acv file mentioned above looks in hex like this:

0004 0001 0008 0019 0000 0060 0017 007F 002E 0099 0057 00B2 009C 00BF 00C9 00CC 00ED 00D9 00FD

The first 3 groups (0004 0001 0008) can be discarded, the other one are the coordinates of the points of the curve in hexadecimal format, the first value the "output" (y-axis) and the second value the "input" (x-axis).
So we got 8 pairs of numbers:

0019 0000
0060 0017
007F 002E
0099 0057
00B2 009C
00BF 00C9
00CC 00ED
00D9 00FD

Converted to decimal values we get :

25 0
96 23
127 46
153 87
178 156
191 201
204 237
217 235

This are the values we need for the PWP crv file.
I have created a crv file with the default curve in Brightness Curve Transformation and the made the changes in a texteditor, like Notepad from Windows.

The finished crv file looks like this :

Curve 1.0
npts 8
style spline
histexpand 0
point 0 0 25
point 1 23 96
point 2 46 127
point 3 87 153
point 4 156 178
point 5 201 191
point 6 237 204
point 7 253 217
end

The npts has to be set to the number of points, 8 in our case here and the numbers of the values we have converted above has to be interchanged, the 2nd value in the list comes first, the first comes in second place.

Finally the screenshots of the curves, please be aware that the PS coordinate system in rotated at 180 degrees in respect to the PWP coordinate system (in the PWP system is black in the lower left corner, in PS ins white)

Thanks Dieter. The explanation was clear. I can write a small program to make convertions automatically.

How about a digital negative for a 'wet' palladium/platinum printing process?

Source: http://www.luminous-landscape.com/tutor ... inum.shtml

You MUST start with a RAW image since you really need a high (12, 14 or 16) bit image. For further information on why, see Expose Right on this site. Using your favourite post-processing techniques you need to end up with an image that’s 1) black and white; 2) inverted (you need a negative image) and 3) rotated horizontally so that in the final positive what is supposed to be on the right will be on the right. The actual order in the layer stack is: original image (flipped horizontally); an adjustment curve; the inverted layer.

Making the negative image in PWP:
(1) create a preference black/white image with a high bit depth, i.e., R=G=B, 48-bit color.
(2) to rotate horizontally: OK PWP's Transformation\Geometry\Mirror/Rotate transformation <-+-> mode on the resulting (1) image.
(3) OK an adjustment curve Fig 5 using the RGB BrightnessCurve transform on the resulting (2) image.
(4) OK an adjustment curve Fig 4 using the RGB BrightnessCurve transform on the resulting (2) image.
(5) click on the resulting (3) image, open the Composite-SoftLight transform, set the resulting (4) image as the Overlay, click OK.
(6) to invert: OK PWP's Transformation\Gray\Negative transform on the resulting (5) curves adjusted image. This is the negative image.

Fig4 [palladium only] curve in PWP5 text form:

Curve 1.0
npts 9
style spline
histexpand 0
point 0 0 0
point 1 9 36
point 2 17 53
point 3 42 73
point 4 231 175
point 5 241 185
point 6 250 200
point 7 254 220
point 8 255 255
end

an approximate Fig5 [palladium/platinum] supplementary curve in PWP5 text form:

Curve 1.0
npts 14
style spline
histexpand 0
point 0 0 3
point 1 23 23
point 2 44 46
point 3 62 71
point 4 77 84
point 5 99 105
point 6 120 120
point 7 143 133
point 8 161 143
point 9 179 154
point 10 196 163
point 11 219 176
point 12 237 186
point 13 255 196
end

Note: the Author's caveats regarding the use of use of his Fig4 and Fig5 curves. They seem to be very setup and environment specific... and perhaps chemical adjustment may prove to be of more benefit then finely tuned negative curve adjustments.

Things considered when translating this article:
(1) The workflow/curves occur in the RGB color space model, i.e., the RGB BrightnessCurve, Composite-SoftLight/HardLight/Filter/SubtractFilter transforms
(2) Curve point designations are on the 1 to 255 tone scale rather than PWP's percentages and the curve coordinate control point designations were [vertical,horizontal] rather than PWP's [horizontal,vertical].

Illustration: original digital image to digital negative [note: the suggested PWP workflow did not reproduce the apparant shadow discontinuity (sky) of the Author's negative image illustration possibly due to the small resolution of the images... and I am not so sure that it is desirable anyway, at least for this image].

Addendum:

I just saw in the Luminous-Landscabe link from Den that in "modern" PS versions the axis of the curve are the same as in PWP, the screenshot in my post is from my old PS6.

For what it's worth, PWP's Color Curves transformation should be able to open Photoshop Curves (ACV) files. Click the Opt button at the top, select Load... and then select the appropriate file type (e.g. Photoshop Curves).

Somewhat related... staying in a 'virtual' realm... and if of interest.

The following in text format is a PWP Tint file [*.cln] that is 2 parts Palladium and 1 part Platinum:

Colorline 1.0
ncolors 25
color 0 0.0000 0.0000 0.0000 0.0000
transition 0 line rgb
color 1 0.0430 0.0430 0.0390 0.0270
transition 1 line rgb
color 2 0.0900 0.0900 0.0820 0.0630
transition 2 line rgb
color 3 0.1370 0.1370 0.1220 0.0900
transition 3 line rgb
color 4 0.1840 0.1840 0.1650 0.1220
transition 4 line rgb
color 5 0.2310 0.2310 0.2080 0.1570
transition 5 line rgb
color 6 0.2710 0.2710 0.2430 0.1880
transition 6 line rgb
color 7 0.3180 0.3180 0.2860 0.2240
transition 7 line rgb
color 8 0.3650 0.3650 0.3250 0.2630
transition 8 line rgb
color 9 0.4080 0.4080 0.3610 0.2980
transition 9 line rgb
color 10 0.4510 0.4510 0.4040 0.3370
transition 10 line rgb
color 11 0.4940 0.4940 0.4390 0.3670
transition 11 line rgb
color 12 0.5410 0.5410 0.4820 0.4160
transition 12 line rgb
color 13 0.5840 0.5840 0.5250 0.4590
transition 13 line rgb
color 14 0.6310 0.6310 0.5690 0.4940
transition 14 line rgb
color 15 0.6780 0.6780 0.6160 0.5370
transition 15 line rgb
color 16 0.7250 0.7250 0.6630 0.5840
transition 16 line rgb
color 17 0.7650 0.7650 0.7020 0.6240
transition 17 line rgb
color 18 0.8080 0.8080 0.7490 0.6750
transition 18 line rgb
color 19 0.8390 0.8390 0.7880 0.7220
transition 19 line rgb
color 20 0.8750 0.8750 0.8310 0.7760
transition 20 line rgb
color 21 0.9060 0.9060 0.8750 0.8310
transition 21 line rgb
color 22 0.9370 0.9370 0.9140 0.8860
transition 22 line rgb
color 23 0.9690 0.9690 0.9570 0.9410
transition 23 line rgb
color 24 1.0000 1.0000 1.0000 1.0000
end

It is dervied from JSetzler's photoshop acv toning curves illustrated/linked here: http://www.setzler.net/?s=tone+curves

Illustration:

Just curious... Is anyone using a 'wet' Platinum and Palladium process? or doing 'virtual' printing?

It has been awhile since I have done any PS 'tone curves' or PWP Tint-ing... and in the process of re-acquiring some familiarity, I simplified the "2Palladium-1Platinum.cln.txt" file to:

Colorline 1.0
ncolors 7
color 0 0.0000 0.0000 0.0000 0.0000
transition 0 line rgb
color 1 0.1410 0.1410 0.1250 0.0940
transition 1 line rgb
color 2 0.2470 0.2750 0.2470 0.1920
transition 2 line rgb
color 3 0.5450 0.5450 0.4860 0.4200
transition 3 line rgb
color 4 0.8120 0.8120 0.7530 0.6780
transition 4 line rgb
color 5 0.9100 0.9100 0.8750 0.8310
transition 5 line rgb
color 6 1.0000 1.0000 1.0000 1.0000
end

Note that in JSetzler's linked web page of PS 'toning curve' illustrations above, he says:

The curves adjustment layer can have an opacity modification to adjust the intensity of the color toning after the curve has been applied.

i.e., one is encouraged to modify saturations of the tone curves to best present image content.

I 'Tint'-ed a recently acquired image with the above 2:1 Palladium:Platinum *.cln file and de-saturated the upper-midtones/highlights a bit to relieve the murkiness of the sky/clouds and water reflection image areas that the un-adjusted tint applied... if of interest an after/before comparison of the initial and final tint versions may be seen here: http://www.ncplus.net/~birchbay/10/IMAG ... _10_94.htm . The adjustment is subtle.

Also for this image, a barely discernable 'grain' was added and the foreground foliage left in-frame to provide a sense of depth and main subject framing.

Nicely done with the anchored boat, Den.

The suggested procedure of modifying brightness and saturation is often a nice touch for adjusting the mood of tinted images. It can, of course, be accomplished by any of several transformations available in PWP. My favorite method (at least currently) is to blend the tinted image with itself using either the add or subtract modes depending on which way I want to go. In the add mode, saturation is decreased and brightness is increased. Usually, less than 10 percent overlay can make a significant difference in the feeling of the image.