Topic awaiting preservation: Silly Difference Trick

Oh, man. Now this cracks me up. My whole desk is shaking I'm laughing so hard. Now, let's see if I can give a run-down.

Start with two photos in the same document. Same size? Sure. Or you can start with one photo, copy it, and filter fest it.

Set the one on top to Lighten. Like this:

Photo2 < Lighten
Photo1 < Normal

Copy merged and paste. Turn off Photo2. Like this:

P2 Lighten < Normal
Photo2 < turn it off
Photo1 < Normal

Set PS Lighten to Difference. Now like this:

P2 Lighten < Difference
Photo2 < off
Photo1 < still Normal

Copy Merged and paste. Invert it. Turn it off for a bit. Like this:

P2 Lighten Diff Inverted< off
P2 Lighten < off
Photo2 < off
Photo1 < yeah, Normal

Turn Photo2 back on an make it Darken.

Photo2 < Darken
Photo1 < Normal

Copy Merged and Paste.
Set to Difference.
Copy Merged and Paste again.
Ah...

P2 Darken Diff < Normal
P2 Darken < Difference
Photo2 < Darken
Photo1 < ... normal...

Put P2 Lighten Diff Invert over P2 Darken Diff.
Set blending mode to Screen and bring Opacity down to 50%.

P2 Lighten Diff < Screen 50%
P2 Darken Diff < Normal

Copy merged and paste yet again.
Call this Linear Diff.

Turn off all layers except Photo1, Photo2, and Linear Diff.

This is where the coolness kicks in.

Set Linear Diff to Linear Light.
If you have one bottom photo turned on, it will turn into the other photo.
To swap the conversion, just invert Linear Diff.

By using Linear Light on one layer, you can turn one photo into another.
You can go either way.

Too funny.
Even funnier than that, I do have a use for this.

sdiff01.jpg
sdiff02.jpg
sdiff03.jpg

03 is the linear difference

using just 03 and linear light, either photo can be turned into the other

edit:
Found the shortcut.
Exclusion and Hard Light are good.
Maybe tomorrow after I do a few more tests.

(Edited by warjournal on 03-25-2005 04:05)

Okay, I am a genius and an idiot. I know that there are other geniuses out there, but how many of them can match my level of idiocy?

Photo2
Photo1

Invert Photo2
Reduce Opacity to 50%
Copy Merged

That's it.
You can now use Linear Light to convert one photo into the other.

dude, just record a photoshop action and post it here, so i dont have to read your instructions.

Thought about that.
That again, my 3rd post is short and sweet.
It's all you need.

Don't get lazy on me Grum and say that you can't handle a few steps.

The first set of instructions is far more fun though.

Jason

Big ChOps = big fun
Like the ChOps I did for extracting hue.
egads

Never ceases to amaze me how far the simple tools can be pushed.

Reminds me of Hollow Man. The thing about going from A to C and skipping B. Sometimes I go through B, babble, ramble, di, tri, sept, delta, gamma, and sigma - just to get to C. Maybe that's why I sometimes talk about long way first and then the shortcuts.

Not sure if my ideas for this difference trick will pan out. One of my ideas will require 6 channels of information and I'm not sure if/how I'll be able to test it. I'm not even sure if I'll be able to get the proper derivatives, either. I don't care for calc, but it does have it's uses.

I think I'll put his on the backburner for a bit while I work on some of my other ideas. Like my magnetic field idea. After all, Hue Squish is a magentic field - why not extend this idea to higher dimensions?

(Edited by warjournal on 03-27-2005 14:11)

i'm not getting the trick...

could you explain?

Arthemis,

The basic idea is to get the difference between two photos.

However, Difference blending mode won't work for this because it's |B-A| or abs(B-A) depending on how you want to look at it.

What we need is (B-A)+128.
That is (kind of) accomplished with Normal mode and Opacity = 50%.

Once you have the difference in that manner, you can use Linear Light blending mode to 'convert' one photo into the other.

This is definately and interesting trick, but what are the practical or potential artistic capacities of it? Forgive me, but I am new to Photoshop (discovered Fireworks first).