Using the Emboss transform to increase detail/texture...

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Using the Emboss transform to increase detail/texture...

Postby den » September 28th, 2014, 11:22 am

The following can provide a nuanced alternative to traditional sharpening methods for increasing micro-contrasts of small, fine detail/texture based upon an image's main light source direction...

(1) Start with a near preference full range, tone/colors, sharpened, brightness/contrast, and low luma/chroma noise image, Img0... ...where no further 1:1 registration to/from another image version is anticipated... ...i.e., 1:1 Cloning, Composite-Blend, etc...

(2) click on Img0 and open the Transformation/Special Effects/Emboss transform... settings: Amount=100; Radius=1.0; Method=Normal; Height=1.0; and Color Space=RGB... ...then select the Angle so that the small circle is in the direction where a shadow would lie as the result of Img0's main lighting source... OK, creating Img1.

(3) click on Img1 and open the Mask Tool - Brightness Curve... ...lower-left Apply Add a Stair Step curve [0,0; 50,0; 50,100; 100,100]... OK, creating Mask1...
...[select Stair Step curve type and "right click-hold-drag-release" the right upward pointing black arrow located at 100,0, moving it left to 50,0]... or ...[copy, paste to a plain text editor [Notepad], and 'Save as' a <name>.crv file, the following:

Curve 1.0
npts 2
style step
histexpand 0
point 0 0 0
point 1 128 255

for use with Mask Tool - Brightness Curve OPTions Load...]...

(4) click on Img0 and open the Composite transform where Input Image=Img0; Input Amount Mask=Mask1; and mask white=67 and mask black=100... ...the Overlay=Img1; Overlay Amount=67; Operation=Hard Light; and Alignment=none... ...adjust settings to preference while monitoring an Auto [checked] updating Preview at a 1:1 Zoom factor to avoid viewing anti-aliasing effects... OK, creating the embossed image version of Img0.

1) the suggested Compsite-Hard Light Input Amount mask settings set the light half of the embossing to two thirds of the dark half... ...i.e., 67/100... reduce objectionable light half edge contrasts... ...set this ratio to your own preference.
2) the suggested Composite-Hard Light Overlay Amount is an initial amount to be adjusted to preference.
3) using the RGB color space to generate the Emboss image, Img1, will essentially confine the suggested Composite-Hard Light blending to changes in tone [Luminance] near the affected edges... ...i.e., no changes to colors [Hues, Saturations] as would be the case if HSV or HSL color space generated Img1's were to be used as the Overlay. If the HSV color space were to be used, for example, an extra step is needed to Extract Img1's HSV-V channel; then use that channel image as the Overlay.
4) Emboss transform Ratio and Height settings will displace pixels... the suggested workflow should be the last process of Img0's overall development.

A 1:1, 300x365 pixel image area crop of a 3456x2304 processed image... ...left is Img0... ...note the slight increase in texture of the water fall and cliff face shown to the right:
1-1_crpd_image_area_comparison.jpg (63.54 KiB) Viewed 1919 times

Have fun experimenting... ...try different Emboss transform Radius and Height settings... trials suggest keeping both around 1.0 for photo realism.


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