A Zone System Exposure Control

[photoken]

Here's something I've been thinking about for a while:

It might be interesting for PL to have an exposure control that modified the lights and darks within exposure zones in an image.

Now that PL 20 has an Exposure Control, that control could be used as a basis for a new Zone System Exposure Control:

Zone System dialog.jpg

The control would assign pure black values in the original image to Zone0, and pure white values to Zone10. The remaining image values would be equally split between the other nine zones. The buttons at the bottom of the dialog would select the zone to which the sliders at the top would be applied. For example, if the Zone5 button was selected, the Lights value slider would only affect the lightest values within the middle zone of exposure.

I know some of you (Alan ?) are fans of using multiple luminance masks that have been calculated to represent various tonal ranges. It seems to me that this Zone System Exposure Control would mostly replace (or possibly eliminate) the need for those luminance masks and the overhead of creating and applying them.

Although I'm thinking in terms of using this on B&W images, if this new ZSEC used the "L" (Luminance) channel in the Lab colour space, the control would also be applicable to full colour images, since the image colours would remain mostly unaffected.

In short, I'm looking for a user-friendly control that would expand the more "technical" manipulations of the excellent Zone System fully into the digital imaging age.

The ZSEC would also correct the problem with the "Offset" slider in the current Exposure Control. I know the control was added to enhance the import of PSD files, and therefore must necessarily duplicate the functionality of Photoshop's control, but the "Offset" slider is much too blunt of an instrument. When the "Offset" value is increased (to lighten the darks), it eliminates the darkest values and makes the image very weak-looking.

(As another side benefit, the ZSEC would also function as a Highlight/Shadow control on steroids. )

Comments are very much encouraged, and welcomed....

[Alan9940]

Hi Ken,

You're always thinking!

In general, I like the concept. However, think about how this might work "under the hood." To my mind, the smoothest and most accurate way to apply your new control is through the use of...dare I say it?...luminance masks. One of the reasons I like these masks so much is because it allows me to have pinpoint control in a very seamless way. If you really want to see the power of these masks, look up Tony Kuyper and/or watch a few videos from Sean Bagshaw showing his use of Tony's TKActions panel in PS. Yes, there is some overhead associated with these masks, but I'm sold!

In addition, but certainly in a more crude way very similar adjustments could be done with the curves tool; especially in PL where we have direct access to the L channel. If the curve is separated into 10 "zones" and one locks down both ends where you don't want any change, then you can manipulate both exposure, contrast, and, by extension, saturation depending on what you're doing. For the finest control, you'd probably want to do this through a mask, so...we cycle back around to...I won't say it!

Alan

[photoken]

Hi Alan,
Thanks for your comments about this. I did, once upon a time, look at Kuyper's concept but for various reasons rejected them for my preferred workflow. That's why I value your thoughts about this, because you've got much more experience using those masks.

To my mind, the smoothest and most accurate way to apply your new control is through the use of...dare I say it?...luminance masks.

I think you might be on to something about the "smoothness" of the ZSEC. Theoretically, manipulating the lightness in discreet zones might lead to more abrupt transitions than what happens when altering a curve in the Curves panel, or with a luminance mask.

But, then again, maybe not. This "smoothness" is something that I can't really decide about until I actually see it in practice....

In addition, but certainly in a more crude way very similar adjustments could be done with the curves tool; especially in PL where we have direct access to the L channel.

Yeah, I'd like to avoid having to deal with creating a curve with a narrow, fussy "S" shape.

In general, does the concept of a ZSEC match what those luminance masks are trying to achieve?

[Alan9940]

Yeah, I'd like to avoid having to deal with creating a curve with a narrow, fussy "S" shape.

Totally agree! I was simply pointing out that similar effects could be accomplished with a curve; not that anyone would really want to work that way!

In general, does the concept of a ZSEC match what those luminance masks are trying to achieve?

In board strokes and as you've presented the concept, yes. But, what a luminance mask will give you is buttery smooth transitions between masked and unmasked areas. Plus, once I have the mask I could apply a slew of adjustments through that mask going way beyond simple brightness, contrast, etc, adjustments. And, as I said, I would suspect something like masking would have to be going on "behind the scenes" to get the effect you're seeking. Or, it's all just numbers and math which is beyond my level of understanding...

Best,
Alan

[levelbest]

This is my first post. Please forgive me if I have misunderstood but it sounds like you are asking about something that LightZone did? LightZone went out of business although it's developer was kind enough to release the code so it could continue to be used. Not exactly open source but still usable.

I would love to see something like that implemented again. Based on the concept of Zones as Ansel Adams used them, moving your mouse over a scale of values showed which values were highlighted. Then you could pull down or push up those values. I found it a very useful tool.

[photoken]

Hi, levelbest,
I've never used LightZone, but it sounds very similar to what I'm asking for. The two main differences are:

• The "Zones" I'm talking about include a range of values (from dark to light) rather than only one specific tonal value.
• I'm asking for a tool that would allow modifying both the lights and darks, independently, within the selected zone.

The "Brightness" slider I showed would move the entire value range of the "Zone" up or down, which approaches what LightZone does for specific values..

[Alan9940]

levelbest,

Speaking as one who used LZ fairly extensively "back in the day" the technique Ken is proposing is quite a bit more sophisticated than what LZ's ZoneMapper tool provided. Don't get me wrong, the ZoneMapper was/is an intuitive tool to modify zonal tone ranges, but, basically, it's nothing more than a curves tool. IMO, it's somewhat crude in its application and doesn't begin to approach the control available via a luminance mask.

BTW, if you didn't know LightZone is very much alive and well; see: http://lightzoneproject.org/

Kind regards,
Alan

[photoken]

Thinking about this request a little more, it probably should not be called a "Zone System" Exposure Control. Because the Zone System is based on discrete tonal values, for the sake of precise terminology it would be better to call this request a Zonal Values Control (or something similar but more sexy ).

[greenmorpher]

That looks pretty good to me, Ken - -I would love it provided it worked in color.

With PhotoLine, I have become a lot better than I was with curves, but I can make an awful mess!

The sliders would be great PROVIDED there was something to adjust the level integration between the adjusted area and neigbhoring areas. An auto setting plus a "soft merge" setting of "n" pixels.

Cheers, Geoff

[photoken]

That looks pretty good to me, Ken - -I would love it provided it worked in color.

Agreed. I think that by working on the "L" channel in the Lab colour space, the control would be equally beneficial for B&W work as well as colour images.

With PhotoLine, I have become a lot better than I was with curves, but I can make an awful mess!

Yes. With Curves, it's definitely "less is more"....

The sliders would be great PROVIDED there was something to adjust the level integration between the adjusted area and neigbhoring areas. An auto setting plus a "soft merge" setting of "n" pixels.

Nix on that. It would add way too much complexity and not be very intuitive. Alan raised the point about smooth transitions, and it's a valid point. It's a question that I can't answer until I see the control in practice.

[greenmorpher]

The sliders would be great PROVIDED there was something to adjust the level integration between the adjusted area and neigbhoring areas. An auto setting plus a "soft merge" setting of "n" pixels.

Nix on that. It would add way too much complexity and not be very intuitive. Alan raised the point about smooth transitions, and it's a valid point. It's a question that I can't answer until I see the control in practice.

What I was thinking of was something similar to the feathered edge in selection with the lasso and whatnot. That's not too hard, surely.

Cheers, Geoff