Grey Chanell (in Grey mode) selection problem?

[SeniorS]

Hello!

I have another question about GREY images.

Example:


CTRL+click on grey channel theoreticly (by my theory) make selection from white depending on its value. So cuting out must leave transparent greyscale image. But it don't (okey, it do, but changes black value):


The same selection inverted and filled with 100%K gives correct result:


Is my "theory" about CTRL+click selection wrong?
Becouse for my point of view, both ways should give same result.

P.S. I must be miss something.

[dv8_fx]

Patience SeniorS... I'm still trying to figure out your problem... lol....

[iDad]

lol so am I

[SeniorS]

I think problem is in CUTING. Becouse selection is okey (checked it and on 25% grey is 75% selection). Maybe something with antialiasing.

[SeniorS]

Problem - CTRL+click then CUT then flatern (or on white background) and image (theoreticly) should be the some as original.

[iDad]

not sure what you are saying your percentages don't add up?

[SeniorS]

Something like that.

First image is original. Then i press CTRL+mouse click on grey channel in Channels panel. That creates white value selection. Now i CUT it and expect that now i have transparent image with black values exact as original. But when i flatern it or put on white background (or by eye drop) i notice that only value which is correct is 100%K all others changed (showed in second image).
Third image shows that selection itself got no problem. Because the same selection inverted and filled with black gives correct result.

So, after thinking (and 2 cigaretes) i assume that cutting works not the way i understand.

[iDad]

Sorry still confused, none of those images look transparent to me... I must need more caffeine lol

[SeniorS]

My fault, should post gifs or something.

Here is psd file with all that in one file:grey.psd

[dv8_fx]

Wake up, iDad, wake up....

I think understand, I hope.

When you make your selection, PS will select whatever shade of white in the the last 3 swatches (75, 50, 25). Why the 100% swatch wasn't affected? Coz basically there's no shade of white.

So naturally, when you cut / delete the color values within the selection, you altered the black values of the last three.

When you inverted the selection, you are selecting the true value all 4 swatches. You may have filled it with 100%k but the 3 last swatches was filled with it's particular shade of black.

As an experiment.... after selecting the black of the original image..... on a new layer..... fill with white..... it will show you the white opposite of the first image.


iDad.... got an aspirin?.... lol