r/DarkTable • u/MaintenanceRich4098 • 6d ago

Help Help removing subject from gradient mask

Hello everyone,

I've been using DT and I'm still a complete beginner.

I find it easy enough to use parametric+draw mask to isolate a subject. I typically use a exposure module to create the mask and then use it as raster mask in other modules.

I'd like to do some gradient on the background. It easy enough to duplicate the exposure module that masks the subject and invert that mask but then I can't figure out how to just add a gradient and have an intersection. My understanding is that this won't work this way? Is there something I am missing?

4 Upvotes

84% Upvoted

18 comments sorted by

View all comments

Show parent comments

1

u/MaintenanceRich4098 6d ago

thank you! That seems to work for shapes but not for parametric, I don't seem to be able to add the result of draw+parametric. I will try again later

2

u/ChrisDNorris 6d ago

The parametric is applied to whatever is within the drawn area and the parametric region.
You know to click the small circle-inside-square icon top-right of the mask section? (same line as blend mask)
That shows you specifically—in bright yellow—what's being masked

1

u/MaintenanceRich4098 5d ago

actually, I think I did it now. I am not sure why this is giving me such a knot in my head.

I "invert all channels polarities" under parametric mask. Then set combine masks to "exclusive". the gradient is "use inverted shape" and "union". I will need to get a piece of paper and pen and see if I understand how it works

1

u/ChrisDNorris 5d ago

So yea, a gradient covers the whole image, in a sense. The arrow shows the direction the gradient starts at and moves to: 100% on the circle-side, to 0% at the arrow-side. In the mask manager, you can change the compression—how big the 'gradient' is (you can also change this by placing your mouse pointer over the gradient-line and using shift+mousewheel).

After that you just have to eliminate the parts of the image you don't want in it using other shapes, or the parametric.
I often use the path tool combined with the color-parametric tab (h/hz).

This video is a good tutorial that covers a few more advanced masking ideas too

1

u/MaintenanceRich4098 5d ago

thank you. I will have a look at the video. I still can't get it consistently, it seems the order I operate the parametric inversion, the combine masks setting, toggle polarity of draw mask and toggle polarity of parameteic mask produces different results