gradient map mystery

[Jbasya]

I think I understand how gradient maps work, but why does the first screenshot behave as expected while the second one turns everything white? (It's the default foreground to transparent--it says custom because I tried one last thing before bothering you with this question.)

Thanks, Damien. Hope you're enjoying your weekend.

 

Edited May 15, 2021 by Jbasya

[Damien Symonds]

Because white is your foreground colour, of course.

[Jbasya]

But when I reduced the opacity of the white in that little box at the left end, nothing changed.  Same if I added an opacity stop in the middle and reduced it, slid it around—everything stayed completely white. Shouldn’t something start to show through? What am I missing?

white-to-transparent on a black-and-white  probably isn’t the best example, sorry. I had the same problem trying to add a touch of yellow to the whites—a full screen of yellow no matter what I did with opacity stops. Even checking “reverse” didn’t change anything. Can you think of anything I might be doing wrong or overlooking? 

 

 

[Damien Symonds]

I ... don't understand what you don't understand.

The two little squares on top have to be solid black all the time.  They are the opacity of the colours.

The two (or more) little squares underneath are the actual colours that we see.  They are in the same position as the histogram - shadows at the left end, highlights at the right end.

[Jbasya]

That’s how I understand it; but why do you say the squares on top have to always be black? Isn’t the point to control the colors’ opacity? If I want a color to be strong at one end and fade away at the other, isn’t that was those opacity stops are for?

Thanks for your help and also patience!

[Damien Symonds]

4 minutes ago, Jbasya said:

That’s how I understand it; but why do you say the squares on top have to always be black? Isn’t the point to control the colors’ opacity? If I want a color to be strong at one end and fade away at the other, isn’t that was those opacity stops are for?

No.  If you want weaker colour, change the COLOUR.

Opacity is important for gradients, but NOT for gradient maps.

[Jbasya]

Yup, thank you. That was the missing piece, I knew you’d have it. ???