A SplitTone Color Curves (*.cc) for BW images...

[den]

I recently had the occasion to restore a vintage faded sepia print from the early 1900's and re-discovered from my archives a SplitTone ColorCurves file that I adapted from a Photoshop tutorial somewhere/sometime past... ...the suggested *.cc curves may be of interest...

Step 1... ...start with the best possible scan of the faded print...

Step1_ori_595px.jpg (55.63 KiB) Viewed 12979 times

Step 2... process the resulting scan file to restore best possible (preference) gray tone contrasts, details, eliminating noise, specks, dust, etc... ...then Extract its Luminance channel and Convert it to 24 or 48 bit color...

Step2_Luminance_595px.jpg (57.33 KiB) Viewed 12978 times

Step 3... Open the Color Curves transform with the resulting Step 2 image version as the Input... ...using the the upper OPT-ions, Load the *.cc file whose text is shown below... ...the SplitTone curves will tend to show slight bluish tints below a 50% Luminance transitioning to slight reddish tints above a 50% Luminance...

Step3_ClrCrvs-SplitTone_595px.jpg (64.5 KiB) Viewed 12984 times

Copy the following text [PWP7 *.cc file format] to a plain text editor (Notepad), then 'Save as' <name>.cc in a favored folder location:

ColorCurves 1.0
colorspace 2
component 0
npts1 5
style1 spline
histexpand1 0
point1 0 0 0
point1 1 77 69
point1 2 153 158
point1 3 204 209
point1 4 255 255
npts2 5
style2 spline
histexpand2 0
point2 0 0 0
point2 1 77 77
point2 2 153 153
point2 3 204 204
point2 4 255 255
npts3 5
style3 spline
histexpand3 0
point3 0 0 0
point3 1 77 80
point3 2 153 153
point3 3 204 204
point3 4 255 255
end

#Manual ColorCurves RGB channel coordinates [horizontal-vertical]:
#R channel in %: 0-0 30-27 60-62 80-82 100-100
#G channel in %: 0-0 30-30 60-60 80-80 100-100
#B channel in %: 0-0 30-32 60-60 80-80 100-100

enjoy...

...den...

[den]

An alternative to using the Color Curves transform which requires the Convert to color of the Extract-ed Luminance channel, one could use the Tint transform where the Input image is the Extract-ed Luminance channel [8 or 16 bit BW] of Step 2 and the following OPT-ion Load *.cln file:

Colorline 1.0
ncolors 5
color 0 0.0000 0.0000 0.0000 0.0000
transition 0 line rgb
color 1 0.3000 0.2700 0.3000 0.3200
transition 1 line rgb
color 2 0.6000 0.6200 0.6000 0.6000
transition 2 line rgb
color 3 0.8000 0.8200 0.8000 0.8000
transition 3 line rgb
color 4 1.0000 1.0000 1.0000 1.0000
end

Again... ...Copy the above text [PWP7 *.cln file format] to a plain text editor (Notepad), then 'Save as' <name>.cln in a favored folder location. For my Vista 32 OS, that location is: "C:\Users\<user name>\AppData\Roaming\Digital Light and Color\Picture Window\Color Lines\SplitTone.cln"

The suggested *.cln file will produce a resulting image with a 1 to 2% absolute difference in dynamic range with a resulting image produced using the suggested *.cc file and the Color Curves transform where the tranform Amount in each case is 100.

The advantage is that a Convert to color of the Extract-ed Luminance channel is not needed...

...an example of the versatility of PWP...

...den...

[den]

Since I have a forum here, I will pass on another favored *.cln file for the Tint transform... ...it is a meld consisting of 2 parts Palladium and 1 part Platinum... ...going back to the wet dark room days where one could mix their own toning chemicals...

Again... ...Copy the text [PWP7 *.cln file format] to a plain text editor (Notepad), then 'Save as' <name>.cln in a favored folder location. For my Vista 32 OS, that location is: "C:\Users\<user name>\AppData\Roaming\Digital Light and Color\Picture Window\Color Lines\2palladium-1platinum.cln"...

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

This tint will produce the following for the transformed Extract-ed Luminance channel of the original illustration of the OP when used with the Tint transform at Amount=33...

Step4_33-2Pa-1Pltint_595px.jpg (62.31 KiB) Viewed 12912 times

The possibilities are limitless... ...have fun exploring!!!

...den...

[den]

Yet... ...another SplitTone alternate using PWP7's Remap transform...

As suggested previously Convert an 8 or 16 bit BW image to 24 or 48 bit color where R=G=B to use as the Input image to the Remap transform:...

capture_03112014_093338-1.jpg (51.72 KiB) Viewed 12819 times

Again... ...Copy the following text [PWP7 *.colorremap file format] to a plain text editor (Notepad), then 'Save as' <name>.colorremap in a favored folder location. Use 'Remap OPTions -- Load' for the transform color pair/settings... ...the"#" lines designate 'comments'...

ColorRemap 1.0
ncolors 7
tightness 0.200
probesize 2
color 0 0 0 0 0 0 0 0.1000 0.1000
color 1 32 32 32 29 32 35 0.1000 0.1000
color 2 64 64 64 58 64 70 0.1000 0.1000
color 3 128 128 128 131 128 130 0.1000 0.1000
color 4 191 191 191 199 191 191 0.1000 0.1000
color 5 223 223 223 228 223 223 0.1000 0.1000
color 6 255 255 255 255 255 255 0.1000 0.1000
end

# SplitTone3.colorremap file in 'plain text'
# Tends to add blue below 50% Luminance
# Tends to add slight red above 50% Luminance

It is interesting to note the scale used to designate R, G, and B colors for the suggested transforms...
...Color Curves uses a 0 to 255 scale [horizontal, vertical] where a 50% value = 0.5 x 255 = 128 (127.5 rounded up)
...Tint uses a 0.0000 to 1.0000 scale where a 50% value = 0.5 x 1.000 = 0.5000
...Remap uses a 0 to 255 scale where a 50% value = 0.5 x 255 = 128 (127.5 rounded up)

Once this is recognized, it becomes intuitive as to how to modify saved transform files, perhaps fine-tuning them from their 'saved' versions.

...den...

[den]

SplitTones and a fortuitous Fuji X100T lens flare...

DSCF0598_Monument_Valley_Tribal_Park_UT_USA.jpg (132.01 KiB) Viewed 11845 times

...den...