LTG's Bridge - A '2Tone Range' Workflow Example
The Tale behind the Image:
This workflow is the result of a DL-C message board thread which is located here and should be read for the workflow to be completely in context. Initially, the main focus was highlight recovery of the sky and clouds from a CRW [Canon EOS-10D] raw file with further discussion regarding remaining enhancements extending into the mid-tones and shadows and where the transitions should occur.
The original CRW file had clipped highlights. Using Canon's FileViewerUtility1.2, an 'Expose to the Right' JPG image file was created which simulated re-taking the photograph with a -1EV Exposure Compensation setting. This -1EV EC image is the starting image for this work flow and may be downloaded here [warning: 3072x2048 pixels, 2.4MB].
Place your mouse over the image to see the -1EV EC starting image.
. . .A LTG image - - used with permission. . .
. . .Before and After Histograms. . .
Image post-processing consisted of recovering highlights detail [70->100% tone range] in the HSL color space and shadows and lower mid-tones detail [0->70% tone range] in the HSV color space, followed by LCE [Local Contrast Enhancement] and USM [Unsharp Mask] sharpening.
Step 1: Enhance the 70-->100% [highlights] tone range detail.
A: Open or click on the Starting Image and generate a 70-->100% complex highlight tone range mask using a blur = 75 with the Mask Tool.
B: With the Mask Tool remaining active, click on the Starting Image and open the Color Curves transform in the HSL color space and move/add control points forming HSL,L and HSL,S curves as indicated in Screen Shot 1.
C: Click OK creating a working image, Img1.
. . .Screen Shot 1. . .
Step 2: Enhance the 0-->70% [shadows and mid-tones] tone range detail.
A: Open or click on the Img1 and generate a 0-->70% complex shadow tone range mask using a blur = 25 with the Mask Tool.
B: With the Mask Tool remaining active, click on the Img1 and open the Color Curves transform in the HSV color space and move/add control points forming HSV,V and HSV,S curves as indicated in Screen Shot 2.
C: Click OK creating a working image, Img2.
. . .Screen Shot 2. . .
Step 3: Specific image area sharpening to reduce excessive sharpening halos.
A: Open or click on the Img2 and paint a mask with the Mask Tool paint brush [r=80, transp=0, soft=50 and then APPLY Blur=35] over the bridge rails and silhouetted tree limbs/leaves hanging over the left side bridge area.
B: With the Mask Tool remaining active, click on the Img2 and open the Sharpen transform in USM mode and APPLY LCE as indicated in Screen Shot 3, then click APPLY creating a working image, Img3.
C: Click on the Sharpen transform, change Input = Img3, white=0, black=50, r=2, thrshld=3, and then click APPLY creating a working image, Img4.
D: Click on the Sharpen transform, change Input = Img4, white=0, black=50, method=Sharpen and then click OK, creating a working image, Img5.
E: Click OK on the Mask Tool creating a mask image, 'Mask_tree-rails'.
. . .Screen Shot 3. . .
Step 4: Reduce contrast and saturation of the silhouetted tree limbs above left side of bridge.
A: Open or click on the Img5 and open the Mask Tool and Combine-ADD-APPLY 'Mask_tree-rails' and then subtrack the bridge rails and lampposts with the Line-Select tool.
B: With the Mask Tool remaining active, click on the Img5 and open the Color Curves transform in HSV color space and move/add control points forming HSV,V and HSV,S curves as indicated in Screen Shot 4.
C: Click OK, creating the final image, Img6, illustrated in the 'mouse over' images at the top of this web page.
. . .Screen Shot 4. . .
Step 5: Discard and/or archive working images and masks.
While it would be my normal sequence to preform a shadow tone range enhancement after Step 1 and prior to a mid-tone range enhancement, one could do so with Img6 at this point. A '3Tone Range' Step 2B Brightness Curve is applied to Img6 with an active 0->20% shadow range mask [blur = 25] as shown in Screen Shot 5. The 0->20% tone range was more or less arbitarily chosen. There is no significant Img6 property that would call attention to this range. Consideration was given to the fact that significant alteration of the original image's 0->70% tone range had already been made in Step 2 of the work flow above and that a 0->30% tone range might be too much.
. . .Screen Shot 5. . .
It appears that the initial Brightness Curve may indeed enhance the image. Confirm this by zooming in/out the 'Preview'; varying the white 'amount' slider; and relocating the curve control/end points. If more control is needed in relocating the [12,20] control point, mouse 'click-hold-drag' a corner of the Brightness Curve dialog box, increasing the size of the 10x10 grid. The final curve shape and amount applied is highly preferential considering one's tolerance for artistic effects versus photograph reality. For example, just moving the [12,20] control point vertically to [12,30] [adds 10% brightness] and maintaining the full 100% applied amount departs from photographic reality and creates loss of image area detail as shown in Screen Shot 6.
. . .Screen Shot 6. . .
ADDENDUM 2: Look here for an explanation of a BobW '4thMask' inspired elegant alternative for the tutorial's Step 3A mask shown in Screen Shot 7. The alternative mask is formed by: ADD-COMBINE-APPLY Step 1A mask + ADD-COMBINE-APPLY Step 2A mask, INVERT, Blur=5, OK, expand to Full Range in the Levels and Color transform.
. . .Screen Shot 7. . .
Illustrated below is a 'roll over' of a post-ADDENDUM 1 and 2 final image version with the pre-Addendums enhanced version. The top image is the post-ADDENDUM 1 and 2 version. The differences are subtle but discernible. The Addendum 1 changes show most in the the left side tree shadows but also look under the right side of the bridge. The Addendem 2 changes show most in the bridge railings/lamp posts and silhouetted tree limbs above-left of the bridge.
Place your mouse over the image to see the pre-Addendums image.
. . .A LTG image - - used with permission. . .
ADDENDUM 3: Click here to foward to the Addendum 3 web page. This page contains 'dappling effect' illustrations and a Final/Original illustrated 'bridge' work flow summary.
Illustrated Tutorials
You are welcome to see other IMAGEs by DEN.
. . .A LTG image - - used with permission. . .
. . .A LTG image - - used with permission. . .