irregular Gradient fill - DPChallenge Forums

06/24/2004 03:34:20 PM · #1

(and can we get a software forum ? :) )

For editing masks, gradients are really useful to blend the edges. I know how to create gradients for circles, lines etc, but what I'd really like to do is create an irregular shaped selection (e.g., the cut-out of a person) and then make a smooth black to white gradient across the boundaries of that irregular shape, with the gradient at least roughly following perpendicular to the edges of the shape. I normally have tried to achieve that using radial gradient fills and building it up in multiple steps but I'm hoping there is a more efficient way. Any ideas ?

Can you stroke a shape with a rotated gradient brush ?

Could I just fill the selection in a mask and gaussian blur it - I guess that would give the same effect - then a Levels mid-point adjustment would vary the location of the fill. I think I answered my own question...

Message edited by author 2004-06-24 15:35:49.

Canon 12x IS USM (S3 IS built-in Lens) -- 36-432mm (35mm EQ)

06/24/2004 04:49:39 PM · #2

Originally posted by Gordon:

Could I just fill the selection in a mask and gaussian blur it - I guess that would give the same effect - then a Levels mid-point adjustment would vary the location of the fill. I think I answered my own question...

I was going to suggest that, if you have a selection edge, you turn it into a border of 3-5 pixels, maybe feather that, and then either blur the underlying pixels or apply a gradient fill to that skinny selection.

dsidwell

Canon EOS-5D

Canon EF 17-40mm f/4.0L USM

06/24/2004 04:50:39 PM · #3

One thing you might try is to use the selection tool or pen tool to actually trace around a person. If you need to, you can even pasted a person into your photo on a new layer and trace around her/him. Once selected and the little dotted line is humming there in front of you, you can apply the gradient inside your selection.

I do this sometimes with skies. I'll want a nice blue sky, so I select the sky and apply the gradient, but I am able to avoid the mountains or trees or whatever.

Is this what you had in mind?

06/24/2004 04:53:27 PM · #4

Originally posted by dsidwell:

Once selected and the little dotted line is humming there in front of you, you can apply the gradient inside your selection.

Okay - here's the problem then (and GeneralE's reply has the same issue)

What's the direction of the gradient ? I want the gradient to always be perpendicular to the local boundary of the closed shape of the selection.

Think of the 'radial' gradient fill - but instead of having a circular boundary, think body silhouette...

Canon 12x IS USM (S3 IS built-in Lens) -- 36-432mm (35mm EQ)

06/24/2004 05:36:14 PM · #5

Originally posted by Gordon:

Think of the 'radial' gradient fill - but instead of having a circular boundary, think body silhouette...

I tried that ... made a selection, bordered 9 pixels, and ran the gradient tool from the center of the object to well on the outside, and it seemed to fill the border area with a radial fill OK. I also tried filling the border, and progressively shrinking it and filling with darker colors, but it didn't seem to work as well.

06/24/2004 05:37:53 PM · #6

Originally posted by GeneralE:

Originally posted by Gordon:
Think of the 'radial' gradient fill - but instead of having a circular boundary, think body silhouette...

I tried that ... made a selection, bordered 9 pixels, and ran the gradient tool from the center of the object to well on the outside, and it seemed to fill the border area with a radial fill OK.

That's okay when the shape is roughly round - it ends up being very uneven if the shape is say tall and skinny.

rich

Canon EOS-40D

Canon EF 50mm f/1.4 USM

06/24/2004 05:41:49 PM · #7

I don't know if you have tried this yet, since you already mentioned the idea of using stroke on the shape.

Select the shape and copy it to a new layer.
Pull up that layer's properties, and select Stroke.
Select the gradient you want to use.
For style, use "Shape Burst".
Adjust the rest for the look and feel you are after.

This may not be exactly what you are looking for, but it does keep a gradient perpendicular to an irregular shape. This is in Photoshop CS, btw - I am not sure if "Shape Burst" is new or not for Stroke.

Message edited by author 2004-06-24 17:43:46.

Canon 12x IS USM (S3 IS built-in Lens) -- 36-432mm (35mm EQ)

06/24/2004 05:42:03 PM · #8

Ah ... I was afraid of that.

I can't think of anything besides stroking progressively larger versions of the selection with lighter tones.

Will any of the "lighting effects" to this? Using a spotlight pointed straight forward or back?

Canon 12x IS USM (S3 IS built-in Lens) -- 36-432mm (35mm EQ)

06/24/2004 05:42:57 PM · #9

Originally posted by richterrell:

This may not be exactly what you are looking for, but it does keep a gradient perpendicular to an irrecular shape. This is in Photoshop CS, btw - I am not sure if "Shape Burst" is new or not for Stroke.

Sounds right, and probably new for CS.