A Photoshop recipe for black and white conversion

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Charles2
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Joined: November 24th, 2009, 2:00 am
What is the make/model of your primary camera?: Fuji X-Pro 2
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A Photoshop recipe for black and white conversion

Post by Charles2 »

It reads:
A very simple technique involves just two Hue and Saturation (H/S) adjustment layers.

* Create a H/S Adjustment layer with no adjustment. Change the layer blend mode to Color
* Create another H/S Adjustment layer with Saturation at minus 100.
* Return to first H/S layer and tune the black and white effect using the Saturation and Hue sliders.
For an example, the author says, "The Tower Bridge picture had Hue -36 and Saturation +42."

http://www.northlight-images.co.uk/arti ... white.html

How would the recipe translate to PWP? In particular, what does "Hue -36" become in PWP?

A procedure I stumbled on was even more dramatic applied to the author's Tower Bridge example:
  • * Reduce the image to 0 saturation.

    * Make a saturation contrast mask as DEN suggested for other uses: Composite | Absolute Difference, middle gray color for overlay; Levels | Full Range, HSL, and reduce saturation to 0.

    * Composite | Blend the two derived images, weighting the contrast mask an amount around 25%.

    * Brightness Curve | apply an S-curve to increase contrast
den
Posts: 861
Joined: April 25th, 2009, 6:33 pm
What is the make/model of your primary camera?: Canon EOS-350D/Fuji X100T
Location: Birch Bay near Blaine, WA USA

Re: A Photoshop recipe for black and white conversion

Post by den »

A possible PWP translation might be:

(1) the -36 Hue becomes -36/360 or -10% [PWP] ... [a shift of red towards magenta].
(2) the +42 Sat becomes +42/255 or +16.5% [PWP] ...[an increase in saturation contrasts, possibly clipping high saturations].
(3) click on the colored bridge image and open the HSL ColorCurves transform ...[the HSL color space model seems to be PS preferred rather than PWP's HSV model preference].
(4) form a HSL-S BrokenLine curve = [0,0], [83.5,100], [100,100], i.e., move the [100,100] control point left to [83.5, 100].
(5) form a HSL-H BrokenLine curve = [0,0], [90,100], [100,100], i.e., move the [100,100] control point left to [90, 100].
(6) leave HSL-L unchanged ...[its default [0,0], [100,100] curve].
(7) click OK.
(8) click on the resulting step(7) image and (a) Extract the Luminance channel or (b) 16-bit default 'green' Monochrome filter at Amount =100%.

This seems to produce an image with a 10% BW dynamic range differential with the author's 'hs' conversion image. The small resolution of the images [jpeg artifacts] and the water marking make it impossible to confirm an exact duplication.

I don't believe there is a way in PWP to adjust the Hue and Saturation channels in an 'active' mode where the Luminance channel or the Monochrome filtered image results can be 'Preview'-ed.... or is there?
den
Posts: 861
Joined: April 25th, 2009, 6:33 pm
What is the make/model of your primary camera?: Canon EOS-350D/Fuji X100T
Location: Birch Bay near Blaine, WA USA

Re: A Photoshop recipe for black and white conversion

Post by den »

Add'l thoughts...

(1) A workflow with ColorCurve and Monochrome widgets and its Previews can allow 'active' Hue and Saturation changes and the ability to see the Monochrome image version, although it may be somewhat cumbersome and workflow Preview image resolution dependent...

(2) One could also change tone brightness/contrast in step(6) by modifying the HSL-L channel curve but in keeping with the strict intreptation of the PS recipe, it remained unchanged. Might be better to change tone brightness/contrast after the hue/saturation changes so that one can be keep track of what changes what...
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