P: Simulating a center-radiating "linear" gradient

Forum|Forum|2 years ago
July 30, 2023
3 replies
1612 views

Is there any way in LrC to create a linear gradient that radiates out equally from the centre rather than always graduating from the top or bottom?

ON1 Photo RAW has this feature and it was a really useful way to accurately mask a section of the image. I suppose one could replicate it with a very large flat radial gradient but I wondered if there was a keyboard modifier that did this to the LR linear gradient that I'm missing or is this something for the next upgrade?

Correct answer johnrellis

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"a linear gradient that radiates out equally from the centre rather than always graduating from the top or bottom"

Here's a preset Symmetric Linear Gradient that implements Rikk's interpretation (which makes most sense to me now):

It's flat to 6 parts out of 10,000 (0.06%).

Rikk Flohr_Photography

@johnrellis I've been doing this adjustment as a preset for years. I originally built as series of these to simulate the Singh Ray Reverse Graduated filters. Editing the preset by hand allows you to be very precise in your transition between the two constituent linear gradients. https://singh-ray.com/equipment-technique/nd-filters/the-reverse-graduated-nd-filter/

Rikk Flohr: Adobe Photography Org

Suzanne Mathia

Community Expert

Love to know how you created this.

.....Suzanne Mathia

johnrellis

Legend

"Love to know how you created this."

I saved a radial gradient as a preset and manually edited these fields in the preset's .xmp file:

crs:Top="0.35"
crs:Left="-9.5"
crs:Bottom="0.65"
crs:Right="10.5"
crs:Angle="0"
crs:Midpoint="50"

That makes a radial gradient that's 30% the height of the image and 20 times the width of the image. The top and the bottom lines of the gradient are very nearly flat at that width.

You can make such a mask in Develop by continually dragging the radial to the left and then extending its right edge, but it's quite tedious to do it that way.

johnrellis

Legend

"I suppose one could replicate it with a very large flat radial gradient"

It's not clear to me how what you're describing differs from a radial-gradient mask? Are you asking for a quick way to create a radial gradient that's perfectly centered in the photo extending to the edges? I've attached a preset Centered Radial Gradient that does that.

Centered_Radial_Gradient.zip