PWP5/6's HDR/Stack Images Transform -- an opinion

[den]

While I have a strong admiration for the freeware "SNS-HDR Lite" program as an utility adjunct to PWP's exceptional editing transforms/tools... I do not believe PWP should be more automated in its image blending/tone mapping capabilities. The danger of automated programs or sub-routines is that one becomes the recipient of the software developer's preferences. This is the major CON to the PROs that SNS-HDR and/or other fusion programs with automation may have.

PWP has the transforms/tools necessary for image blending and tone mapping to achieve one's preferences and 'artistic' sense...

Example 1:

Ref: http://www.spaceref.com/news/viewsr.html?pid=37328

Imaging experts funded by the Space Shuttle Program and located at NASA's Ames Research Center prepared this image using fusion software to combine six simultaneously captured images they took of the STS-134 launch on May 16, 2011. Each image was taken at a different exposure setting, then composited to balance the brightness of the rocket engine output with the regular daylight levels at which the orbiter can be seen. The processing software digitally removes pure black or pure white pixels from one image and replaces them with the most detailed pixel option from the five other images. This technique can help visualize debris falling during a launch or support research involving intense light sources like rocket engines, plasma experiments and hypersonic vehicle engines.

The six images:

A PWP image blend and tone adjusted image version resulting from the use of the HDR/Stack Images transform and images 3 to 6:


Example 2: http://www.ncplus.net/~birchbay/tutoria ... /index.htm

...den...

[couman]

Well-stated, Den.

Similar commentary might be given for many of special effects programs and plug-ins that have appeared over the last several years. They allow mindless emulation of their creators’ fantasies, but contribute little to the users’ understanding and vision.

[aloomens]

I have never tried using PWP for HDR, since I didn't think It could do Tone Mapping. Can you give a brief example of how you do the tone mapping? There is not an automatic tone mapping transform (correct?). Are you doing it manually using masks?

[den]

The Example 2 web page describes some other alternatives for bringing the visual elements of the HSR/Stack Images resulting image to preference brightness/contrast/color if the the Final Shaping Curve adjustment is insufficient.

...and Correct... ...There is no automatic tone mapping transform as such... ...however MUCH can be accomplished with the 2/3-Zone Adjustment transforms which utilize the HSV color space model and symmetrical tone range masks.

An extraction method for the symmetrical tone range masks of the 2/3-Zone Adjustment transforms is described here: http://www.ncplus.net/~birchbay/tutoria ... /index.htm.

Also consider the merits of sequential mid-tone Local Contrast Enchancement [USM or High Pass] at a medium radius, then a small radius, and finally a large radius... perhaps folowed by Bilaterial and/or Advanced Sharpening.

Because of the precision provided, I tend to use asymmetrical tone range masks, the color spaces, curves, and High Impact Color as described here: http://www.ncplus.net/~birchbay/3tone/3tone.htm.

...I should also add that it is not unethical to use Clone, Paint, and Misc Tools to achieve one's preferences and "vision"... ...particularly for minor de-ghosting corrections!!!...

[den]

...
Reference:
MarkT posted:... ...Since you asked, I made a couple of video tutorials a few years ago (PWP ver 4) that may also serve as examples: http://www.picturetheweb.com/ptw/downlo ... nloads.htm (see "Mask Basics" and "Composite")
...

MarkT's "Mask Basics" [pwp_masks_01.flv] tutorial has more implications then a Levels&Color shadow brightness/contrast/color adjustment using a mask to protect the sky toned image areas of an 'Original' image...

In a broad sense, this is a variation of an image blend and tone-map such that:

(1) A symmetrical tone range mask of the 0% ->20% HSV-V tones [mask white] with a transistion zone of the 20%->42% HSV-V tones [mask grays] to the 42%->100% HSV-V tones [mask black] is used. To soften transistion zone artifacts, a +5 feather is added...

[the Amount mask]

(2) a 'virtual exposure' HSV image version is created having a Levels&Color: -7.8% Black point; 68.9% mid-tone; and a +112.9% White point... and an HSV-S color of 28.7%

[a tone-mapped version of the 'Original'; added color; and viewable only in one's 'mind's eye']...

(3) the 'virtual exposure' was blended with the 'Original' using the Amount mask's white, grays, and black areas in the Levels&Color transform...

[a variation of HDR/Stack Images where the the L&C range and mid-tone sliders act as the HSV BrightnessCurve for Input 2; the created mask is used as Input 1 & 2 Amount masks; Input 1 = 'Original'; Input 2 = 'virtual exposure'; and the Density masks are un-used]...

Hopefully, the implications above provide for further understanding of the inter-relatedness of the PWP transforms/tools and imaging in general...

Thank you MarkT for your tutorial...

[alain]

...
Reference:
MarkT posted:... ...Since you asked, I made a couple of video tutorials a few years ago (PWP ver 4) that may also serve as examples: http://www.picturetheweb.com/ptw/downlo ... nloads.htm (see "Mask Basics" and "Composite")
...

MarkT's "Mask Basics" [pwp_masks_01.flv] tutorial has more implications then a Levels&Color shadow brightness/contrast/color adjustment using a mask to protect the sky toned image areas of an 'Original' image...

In a broad sense, this is a variation of an image blend and tone-map such that:

(1) A symmetrical tone range mask of the 0% ->20% HSV-V tones [mask white] with a transistion zone of the 20%->42% HSV-V tones [mask grays] to the 42%->100% HSV-V tones [mask black] is used. To soften transistion zone artifacts, a +5 feather is added...

[the Amount mask]

(2) a 'virtual exposure' HSV image version is created having a Levels&Color: -7.8% Black point; 68.9% mid-tone; and a +112.9% White point... and an HSV-S color of 28.7%

[a tone-mapped version of the 'Original'; added color; and viewable only in one's 'mind's eye']...

(3) the 'virtual exposure' was blended with the 'Original' using the Amount mask's white, grays, and black areas in the Levels&Color transform...

[a variation of HDR/Stack Images where the the L&C range and mid-tone sliders act as the HSV BrightnessCurve for Input 2; the created mask is used as Input 1 & 2 Amount masks; Input 1 = 'Original'; Input 2 = 'virtual exposure'; and the Density masks are un-used]...

Hopefully, the implications above provide for further understanding of the inter-relatedness of the PWP transforms/tools and imaging in general...

Thank you MarkT for your tutorial...

You lost me, I just don't understand it.

[den]

alain wrote:
You lost me, I just don't understand it.

How unfortunate. Could you be more specific? I would like to be of further help but do not know what's needed.

I was just trying to describe how one could use the Levels&Color transform tutorial at a deeper level as an aid to understanding the HDR/StackImages transform and vs.... and that perhaps unkowingly, we 'image blend and tone map' without specifically identifying the steps and/or terminologly.

;-)

...den...

[couman]

I was just trying to describe how one could use the Levels&Color transform tutorial at a deeper level as an aid to understanding the HDR/StackImages transform and vs.... and that perhaps unkowingly, we 'image blend and tone map' without specifically identifying the steps and/or terminologly.

...den...

Perhaps this is due to the fact that authors of some popularized software have seen fit to apply new labels to old technology under the guise of innovation. The fact is that even a simple "levels adjustment" is a form of tone** mapping. All the more reason to understand what you're trying to achieve and what the transformations actually do before pushing the buttons.

I hope this does not offend anyone -- I mean only to encourage PWP users to take the extra minute to learn the language. In the long run, the results will be far more satisfying.

**using "tone" in the classical sense of "brightness"

[alain]

alain wrote:
You lost me, I just don't understand it.

How unfortunate. Could you be more specific? I would like to be of further help but do not know what's needed.

I was just trying to describe how one could use the Levels&Color transform tutorial at a deeper level as an aid to understanding the HDR/StackImages transform and vs.... and that perhaps unkowingly, we 'image blend and tone map' without specifically identifying the steps and/or terminologly.

;-)

...den...

Den

After watching the tutorial with you're description in another window two times (I do have a cold though) I "understand" every step. I now also understand that you're intention was to give a (for me complex) explanation in other words and terminology to give the analogy between the two.

Alain

[den]

Alain... Thank you to post that you did not understand... ...and thank you even more for the 'considered' second looks at the suggested implications for MarkT's Basic Mask video...

...perhaps you and Others can also see implications for an 'intuitive' understanding of:
(1) a ColorCurves transformation with mask where an HSV-V and HSV-S curves are used for the brightening of the 'Original' images shadows without significantly changing the the upper mid-tones/highlights [sky image areas];
(2) a HSV Brightness transformation, followed by a HSV Saturation transformation, both with a mask to do the same thing; and perhaps...
(3) a 2-Zone Adjustment transformation with the transition slider at a 42% tone, HSV brightness/contrast/color slider changes for the Shadow tone range and no changes to the Highlight tone range...

[note: the 2/3-Zone Adjustment transforms use the HSV color space model and it can be important to recognize which color space model a transform is using when blending/editing changes are made.]

...but I digress... for those that want to understand the HDR/Stack Images transform from a more traditional viewpoint, read JSach's white papers:
(1) Extending the Dynamic Range of Film;
(2) Stacking Images; and
(3) the 'F1 Help' when the HDR/Stack Images transform is 'active' in PWP's work space...
...where actual camera exposure image files rather than 'virtually created' image versions are blended... ...and where the math is more straight forward based upon traditional definitions of 'camera exposure' rather than in the 'artistic' approach ['does it look right?'] that was used to create Example 1.