How to use gradient mask layer

[Briansdad]

Specific goal: correct flash exposure bright in foreground to darker in background.

I believe I want to:

(1) Create a background layer
(2) Created a gradient mask layer
(3) Create a correction layer[/list]

I can't seem to do step 2 with the effect I want. Can you help?

Bill

[LeviFiction]

Actually, kind of fun, adjustment layers have their own built in masks.

However, your problem is a little vague. What kind of gradient are you hoping to make? Or what struggles exactly are you having?

Technically a gradient mask is simple, you have the mask, you select your gradient, and your use the fill tool to fill in the gradient. It'll span the entire canvas, or if you have a selection made, it'll span the selection. And all of the settings for gradients are kept in the color picker. So it's a lot of trial and error getting the gradient just right.

But, maybe we can help you if we knew more of exactly what you're aiming for.

[Briansdad]

OK, more specifically: It's a flash photo of a large group of people arranged in 4 lines. The front row are sitting in chairs with three rows standing behind arranged by height. Front row is well exposed, at the bottom of the image. As the eye move up and toward the back rows the images is progressively underexposed. I want a gradient mask that will mask the well exposed area and gradually allow increased application of exposure compensation (adjusting the exposure upward) from where the exposure start to fall off to the most underexposed part of the photo. Does this help?

Bill

[PS: I can not share the image as not all the subjects want their image shared with the world.]

[hartpaul]

If you have the Raw image, you can process that to give steadily better exposures (usually up too 2 stops) and finish with say 5 images going from slightly underexposed front row through to best exposed back row (with front row overexposed), then use HDR exposure merge to blend the images together . This may be your best option as a gradient is usually linear and will not take account of a tall person in the front row not requiring the exposure of the second row which they overlap. I could see you using a gradient mask and then having to paint adjustments on lots of areas where there is overlap.

[LeviFiction]

Could also use a luminance mask. This is a mask that uses the image itself to create the mask.

1) Select the background layer

2) Duplicate the layer

2) Make a new mask layer from image (Layers - > New Mask Layer -> From Image )

3) Make sure "Source Luminance" is selected and hit OK

This will select the brightest areas of the image with the greatest effect. The darker areas will get less of the effect.

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You could also try the Highlights, Mid-tones, and Shadows adjustment without any masks. Depends on the severity of the exposure.

[Briansdad]

HeartPaul: though I "always: shoot RAW for portraits, I screwed up on this one, JPG only here. I will give HDR a a shot anyway after apply a range of exposure correct to several images. Will post later outcome. Haven't the time right now. I use HDR often enough and haven't a clue why I didn't think to apply this technique to this situation. Good suggestion I think.

LeviFiction: I followed your directions i think, just to see what I get. But, I need the opposite application of effect. You wrote "The darker areas will get less of the effect." What I need it to increase the exposure in the darker areas. The lighter areas are good as is. Following your instructions above, I actually saw no effect at all on the image on screen. Was I supposed to something more to render the effect (whether it's the effect I wanted or not)? Is the order of the layers an issue here?

Bill

Layers -1 -P1010201-PP1.JPG (12.9 KiB) Viewed 4098 times

[LeviFiction]

Just invert the mask.

There should be an option to do so right on the layers palette, or you can use the layer's menu. Or use the "Negative Image" effect from the Image menu. That will flip the mask so that the darker areas receive the largest bit of the effect, and the white areas the least.

Another way to do this is, when creating the mask there is an "invert" option just make sure that is selected and it'll mask out the brightest areas and leave the darkest.

As for the effect, the mask is simply a mask. You still have to either add an adjustment layer inside the group, or actually apply the effect to the layer that's directly below the mask. Just making sure.

[Briansdad]

I am not done with this thread but am extremely busy for the moment. I will be back in a couple of days. thanks you for your help up to now and your patience.
Bill

[Briansdad]

OK, after a LOT of trial and error, I got what I want. I created an example so I could share here what I wanted to do and how it was done. In the sample image the background, distant area, is too dark but the foreground is fine. [This is just a mock-up for demo purposes only, not an example PP excellence!] So the "original" looks like the bottom image below. [I have trouble getting these images in line where I want them to appear in this post - oh well...]

The first image is a screen capture of the PSP editor with the PP I was going for. After I figured out how to create a gradient mask my biggest problem was that I was getting the Adjustment layer in the right order of the layers.[attachment=0]Sample.bottom is ok - back is dark.jpg

Bill