Stroker

Hue Extraction via ChOps

Max Only

Start with a photo.
Go to Channels palette.
Copy Red for 'Red copy'.
Image > Apply Image using
Channel: Green
Mode: Lighten

You've just compared R to G and taken the lighter of the two.
Let's toss B into the Mix.

Image > Apply Image using
Channel: Blue
Mode: Lighten

You should now have the lightest pixel of R, G, and B.
Or, if you prefer, Max(RGB).

I call this Max Only.


Min Only

Same as Max Only, except use Darken.
I call this Min Only.


Diff(MaxOnly,MinOnly)

In channels palette, do Max Only and Min Only.
Image > Apply Image to get the Difference between the two.

Believe it or not, but this is Sat in 'greyscale mode'.
Go ahead and cut-n-paste it into the layers palette and use the G-Map hack.


Minus Min

Now, some more ChOps to extract Sat, but this will be 'RGB mode'.

Do Min Only in the channels palette.
Cut-n-paste it over the original in the layer palette.
Invert it.
Set blending mode to Linear Burn.
Feel free to Copy Merge, Paste, and/or trash layers.

I can this Minus Min.

Now, the result preserves Sat.
Go ahead and set Minus Min to Saturation.
Clip a Levels/Curves Ad-Layer and get crazy.

Cool, huh?
It's even better if you bother smoothifying.


Now, that is the ground work for extracting Hue with ChOps.
The technique that I talked about before wasn't really that great. Easy and certaintly functional, but way too much wiggle for my tastes.
I can do better, damn it.

So I set about finding and understanding the 'anomolies'.
Wow, talk about a trip. I was all over the place.
I even did some 'squaring the circle' type stuff.

Resorting to a bit of trial-n-error, I found something rather odd.
Because of that odd thing, I was finally able to extract raw hue in a proper manner.

Turns out that half of the trick is in 'normalizing Lum in a manner conducive for HSB work'.
The other half of the trick is in avoiding Lum all together.

Alright, follow this as best as you can.

Do Minus Min. Make sure it is on it's own layer in the layers palette.
Copy Minus Min.
Invert the copy.
Do Min Only on the copy in the channels palette.
Cut-n-paste the Min Only into the Layers palette.
Clip it to the first Minus Min (trash the inverted copy or turn it off).
Set blending mode to Linear Dodge.
Bring Opacity down to 50%.

Something like this:

---Minus Min inverted, Min Only-ified, Linear Dodge 50%
-Minus Min
-Original photo

What you are now looking at is an image with 'normalized Lum for HSB'.

To top it all off, ad an HSB Ad-Layer and bring Sat all the way up to 100%.

Now you should be looking at raw hue in all of it's goodness.
Although, any Sat=0% in the original will be 50% grey.

:whew:

It's work, but it's fun.
And it's an excellant exercise in ChOps.

I haven't tried it, but you should be able to record some Actions to help with all of this.
Or you can use Filter Factory or Filter Meister.