False Profile/Multiply through Mask

jjbongjjbong Major grinsPosts: 244Registered Users Major grins
edited January 19, 2011 in Grad School
One of the PPW tools is what Dan Margulis calls False Profile and Multiply through a Mask, and
pathfinder suggested a providing description and example of this.

It is intended for images that have two very distinct sections, one light and one dark,
like my shot of the Coloseum in a different thread:

[thread]185327[/thread]

But it can also be used with images that have a much less extreme issue of the same
sort, like this image of Villa Torlonia, a lovely villa outside of the walls of
Rome (that Mussolini appropriated as his residence):

1152006087_FoHAu-XL.jpg

It doesn't look so terribly bad, But the interesting parts of the image are quite dark, and
there is an interesting part of the image on the right that is much darker than the rest of the image.
I'll use this as an example for the technique.

Dan discusses False Profiles in Chapter 15 of Professional Photoshop 5th edition, but
has not documented the False Profile/Multiply through a Mask technique in his books,
as the PPW postdates the latest book. I looked through the threads on his book in Dgrin
for a discussion of Chapter 15, but I couldn't find any. I found a few references to using
them, but not much else.

The use of False Profiles is based on an insight on how to achieve certain results, and
a specific way to do this in PS. Unfortunately, the concept of False Profiles is difficult
to understand, and both the creation and use of them is fraught with opportunites to
make mistakes. Fortunately, it turns out that there's another, much easier way to do
exactly the same thing. This was discovered by others exploring the PPW, and I've seen
some posts from Dan saying that he does it himself in certain cases. So I'll not talk at all
about False Profiles, and instead discuss the simpler, equivalent mechanism.

The core idea is very simple. You have an image like the Villa, where you want to
lighten part of it and at the same time not lose the contrast in the lighter parts. First you
lighten the entire image, taking care not to blow out any part of it. Then you
darken what were the light parts, without darkening too much what were the dark parts.
The first part you do by changing the image's gamma, the second by multiplying the
result through a mask.

Note that I am using PS CS3. In later versions, the user interface may vary somewhat.

Beginning in PS CS3, you have the ability to change the gamma of an image. You do
Image->Adjustments->Exposure and you get this dialog:

1152018563_QEZM9-O.jpg

You adjust the gamma by moving the slider to the left to lighten the image, and to the
right to darken it. You don't have to know anything about what gamma actually is or
what the numbers represent. Just play with the slider to get the effect you want.
Unlike more standard ways of lightening the image, adjusting the gamma will do so without
blowing out the highlights.

For this image, for example, I adjusted the gamma by 1.4, with this result.

1152018484_29sKR-XL.jpg

If you understand what gamma is, note that I am not setting the gamma to 1.4, but
adjusting it by 1.4, whatever that means to PS (I haven't found exact documentation
for it; I have read posts that claim that it's a relative adjustment, i.e., multiplicative
to the current workspace gamma).

The whole image is lighter, and nothing is blown out. Of course, the original light
parts don't have the contrast they did, but that's for the multiply step.

You duplicate the background layer, set the mode to Multiply, and then duplicate the
top layer again. On some images, you will do this multiple times. Then you merge all of
the multiply layers down into a single layer. Here we'll use just two multiply layers
(layers before the merge):

1151994131_ZYvvJ-O.jpg

This is what you get:

1152016979_GMC2x-XL.jpg

Pretty awful, at this point. We have restored contrast to the highlights, but the rest
of the image is worse than where we started. What we want to do is get the lightening effect
of the gamma change in the darker parts of the image and the effect of the additional multiply into the
lighter parts of the image. The way we do this is with a layer mask. We want a mask that's
light in the light parts of the image and dark in the dark parts. That's not hard at all to
build, as probably each of the individual R, G, and B channels have this characteristic, as
does the composite RGB channel. So we just have to pick out the best one.

Merging the multiply layers, and adding a layer mask:
1151994223_c86Lo-O.jpg


Set the layer mask using the Image->Apply Image (when you add the layer mask,
the layer mask itself is automatically selected, so that's where the Apply Image target is).
You have 8 choices for a layer mask in RGB:
each of the R, G, and B channels and the composite RGB, and you can select either the
Background layer or the Merged layer. Since the Background layer is lighter than the Merged
layer, using one of its channels will result in a darker image overall (since the mask will
be relatively light everywhere, allowing the multiply in the top layer more effect). Conversely,
using a channel from the Merged layer will result in a lighter image overall.

You can cycle through these choices in the Apply Image dialog and select the best one. Here,
I chose composite RGB from the Background layer, as I liked the sky better and I knew I could
improve the villa. But you could go in the opposite direction and choose the composite RGB
channel from the Merged layer and use other techniques to get a better contrast in the sky.

As is usually the case with masks, you want to blur them. For this technique, a pretty big
blur (30px or so) usually works well, although I've found cases where it generates
unacceptable halos. Here, I applied a Guassian Blur, 30 px. to get this:

1152008861_CVmAP-XL.jpg

It isn't finished, but it's a much better base for the standard techniques than the
original. The shadows are lighter, and there's still good detail in the mid-tones and
highlights.

That's bascially it. You use the gamma slider to lighten the image, you choose how
many layers to multiply, you choose a channel for the layer mask (from 8 choices),
and you blur. This becomes the base image for your normal workflow.

Using the rest of the PPW, I ended up with this:

1152017492_5TM4F-XL.jpg

I am happy to provide the missing steps, but the point of the post was the gamma
change/multiply through mask technique, so I'm omitting the rest of it for now.
John Bongiovanni

Comments

  • pathfinderpathfinder Drive By Digital Shooter western IndianaPosts: 14,417Super Moderators moderator
    edited January 11, 2011
    "The use of False Profiles is based on an insight on how to achieve certain results, and
    a specific way to do this in PS. Unfortunately, the concept of False Profiles is difficult
    to understand, and both the creation and use of them is fraught with opportunites to
    make mistakes."

    I found understanding Flase Profiles challenging also, and I confess I have not really thought about them since the book review here about "Professional Photoshop." I will have to ruminate on this post for a bit.

    Is the RAW file for this image available, John?
    Pathfinder - www.pathfinder.smugmug.com

    Moderator of the Technique Forum and Finishing School on Dgrin
  • jjbongjjbong Major grins Posts: 244Registered Users Major grins
    edited January 11, 2011
    pathfinder wrote: »
    I found understanding Flase Profiles challenging also, and I confess I have not really thought about them since the book review here about "Professional Photoshop."

    I think just using the Gamma slider as a way of lightening/darkening without blowing-out/plugging makes the whole
    technique more accessible. You don't have to think about what's going on under the covers. Pre-PS3, you couldn't
    do this, so you were stuck with the False Profile mechanism.

    I have to say that I find the insight here impressive, even if the initial mechanism was fairly difficult.

    I have compared this approach on several of my images with other mechanisms: the Shadow/Highlight adjustment,
    and what Dan calls Shadow/Highlight on Steroids (which had been my default approach to an image like this):

    [thread]64165[/thread]

    In every case I looked at (admittedly a small number), the Gamma/Multiply gave me superior results.
    Is the RAW file for this image available, John?

    It's on its way to you.
    John Bongiovanni
  • crimsontwocrimsontwo Beginner grinner Posts: 1Registered Users Beginner grinner
    edited January 11, 2011
    I've just finished watching a chapter from Margulis' "There are no bad originals" tutorials and decided to look up more info on the false profile method that he demonstrated... when this post showed up in Google :)

    Good tip on adjusting gamma, and is a much simpler method (although creating & using a false profile takes just a couple of clicks). Can't say I like your final result after using PPW though... halos above the rooftop, over-sharpening, etc. but the post-gamma corrected photo looks great.

    Thanks and cheers.
  • pathfinderpathfinder Drive By Digital Shooter western IndianaPosts: 14,417Super Moderators moderator
    edited January 18, 2011
    Sorry abut the delay for getting this image up John, but I wanted to spend at least a day reflecting on my edits. Here is my latest post with your Villa Tarlonia image.


    I just received the Raw file for John's latest image, the Villa Tarlonia, with the steps in the shade in front of the white building. Below is an uneditied jpg from the dng file, it should match the frame put up by John.

    1161190238_5cvvz-XL.jpg

    The Raw file -- ( _MG_3249.dng ) is available here - https://public.me.com/path_finder

    I have spent a couple days looking at this image, trying to decide how I best want to render this image.

    I suggest you get a copy of the RAW file and follow along in LR3. as I list my editing steps as I work through them. I will not be creating and uploading a picture for each step - just too much work involved.

    My editing is done on a MacPro with a 30 in Cinema Display calibrated with an i1D2 hardware colorimeter, and with Lightroom 3, not Adobe camera Raw for this image.

    I began by trying several different color balances, AWB was too blue, Shade was too warm, but I found Auto rather pleasing, and decided to just accept Auto for my color balance which was slightly between AWB, Sunlight and Shade.

    I did not feel the Exposure needed altering, as there was data across the entire histogram, with just a bit of a spike on the right hand side, so I began with the Recovery slider, and raised it to 14. This recovered the blown highlights at the right side of the histogram, which represented the clouds in the sky. I reduced the black point to 4, as there was a fair amount of clipping in the shadows, seen by holding down the Option/Alt key as I adjusted the Black slider. I then slid the Fill LIght slider to the right to open up the clipped shadows, and felt a value of +26 worked nicely.

    I raised the Brightness +4 to 54, Clarity to 16, and Vibrance to +23. Good things are already happening to this image.

    I felt the sky was too bright at this point ( as did John who selectively darkened his sky as well ), and darkened the blue sky, by sliding the Blue Luminance slider to the left to - 66, to create some drama in the sky.

    Next was Sharpening with a Value of Amount 63, Radius unchanged at 1.0, Detail bumped to +27, and Masking to 39, to limit sharpening just to major edges in the image. The mask used for sharpening is visible by holding down the Option/Altkey while you adjust the Masking slider. I wanted to limit sharpening in the sky, so it was black in the mask at this point. WHen I let go of the Option key, the color image returns.

    Luminance Smoothing was raised to +10, Detail and Contrast left unchanged, and Color raised to 38, and Detail left to 50 for my noise reduction settings.

    I darkened the clouds in the sky a bit more, by using the adjustment tool in the Curve palette, to pull down the curve a bit in the right upper quadrant.

    I felt the perspective needed some correction too, so I adjusted the Horizontal slider in the Manual lens correction box, to a +4, and the Rotate slider to a +2, and the Vertical Perspective to a value of -8. I think cropped just a smidgeon to clear out the bare corners left after the perspective corrections. I heartily recommend the readers spend some time playing with the Horizontal and Vertical sliders to get a feel for how they can correct lens perspective errors, much like a tilt shift lens can. I straightened up the planter in the foreground, and corrected the perspective of the shite building as well.

    Next I enabled the lens profile for the EOS 24-105.

    At this point I thought I was almost done, but then, I noticed a white exclamation point in the lower right corner of the main window in Lightroom. This was Lightroom telling me that the image had been processed via the camera profiles from Adobe version 2003, and asking if I wanted to update the file to 2010 profiles. I did want to update as the newer profiles are much, much better, so I dropped down to the Camera profile box and switched to 2010(current) and was basically done with this image.

    Each of these imaging steps were done without real time review of John's edited version earlier in this thread

    As I compare these two images, I find my color balance is warmer in the building shade than John's, and I have opened up the shadow detail in the foreground orange planter and tree leaves in the shade quite nicely. I think mine does not have as much local contrast sharpening yet as Johns, but mine was basically global Raw conversion, and could be sharpened more in Photoshop if needed. Mine is sharp enough that I can clearly see the brunette sitting down behind the three men walking, outlined between the legs of the two men on the right of the group of men. She is holding a newspaper, and wearing a purple scarf. Grain in my image is minimal as expected at ISO 100.

    Here is my final image

    1161190276_CkX6t-X2.jpg
    Pathfinder - www.pathfinder.smugmug.com

    Moderator of the Technique Forum and Finishing School on Dgrin
  • jjbongjjbong Major grins Posts: 244Registered Users Major grins
    edited January 19, 2011
    Nice job. I like the overall warmth of it.
    John Bongiovanni
  • pathfinderpathfinder Drive By Digital Shooter western IndianaPosts: 14,417Super Moderators moderator
    edited January 19, 2011
    It is always hard ( for me anyway ) to decide how to color balance an image that has important aspects in sunlight and shade. This was kind of compromise between the two.

    I learned more about the lens adjustment sliders in Manual Lens Adjustments in LR3. They work quite nicely, and easily. I will continue to make use of them in the future as well.
    Pathfinder - www.pathfinder.smugmug.com

    Moderator of the Technique Forum and Finishing School on Dgrin
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