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+--- Thread: Brighten Portion of Image? (/Thread-Brighten-Portion-of-Image)
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Brighten Portion of Image? - tspence - 08-12-2017
Can't figure out what I'm doing wrong. Trying to lighten the face of the girl in the attached. Steps I took:
Duplicate layer.
Use ellipse tool to select face.
Adjust selection as needed (see attached - overbrightened for emphasis).
Use eraser tool - fuzzy brush at 30% or so opacity - to get rid of line between adjusted and non-adjusted part. Here is where I get unintended results. Why is the eraser making a white path? Shouldn't it fill the erased part with the full image underneath?
What am I going wrong?
Thanks!
RE: Brighten Portion of Image? - dinasset - 08-12-2017
Simply you omitted this step:
- on the dupicated layer: Layer/Transparency/Add Alpha Channel
Try
RE: Brighten Portion of Image? - rich2005 - 08-12-2017
For that image, I would try:
Add a white layer on top
Put that layer into overlay mode
Add a black layer mask: Layer -> Mask -> Add Layer Mask and choose Black (full transparency)
It should look like this: http://i.imgur.com/tfbNujU.jpg same as the original.
Click in the layer mask (the black square) to make it active, it is active if it has that white border.
Change the foreground colour to white, choose the most fuzzy brush you have (probably the one shown in the screenshot)
With a large size, just click once over the head, add a couple more clicks as required.
something like this: http://i.imgur.com/bbUNwxN.jpg
When you screw it up, just fill the layer mask with black and start again
RE: Brighten Portion of Image? - Ofnuts - 08-12-2017
Because when there is no alpha channel, erasing is like painting with white?
What you really want to do is
- add an alpha channel to the top layer:Layer>Tranparecency>Add alpha channel (so this layer can be transparent)
- to be able to tweak the opacity, add a "Layer mask"; Layer>Mask>Add layer mask. In the layers list the mask preview appears near the layer preview. you can select if your tools apply to the mayer or to the mask by clicking on the adequate preview. The status bar (bottom of image) tells you if you edit the layer (say "layer_name") or the mask ("layer_name mask")
- now you can "paint" the opacity on the mask, what is black is transparent, what is white is opaque. In your case you'll use a soft brush so that it produces grays on its edges. You can correct errors by painting in the opposite color...
- when happy with the result: Layer>Mask>Apply layer mask.
RE: Brighten Portion of Image? - tspence - 08-12-2017
Thank you all for the prompt and detailed replies! Will try these and report back. Not quite sure I understand the concept of adding an alpha channel but will give it a whirl. I appreciate the help.
RE: Brighten Portion of Image? - Ofnuts - 08-12-2017
(08-12-2017, 02:27 PM)tspence Wrote: Not quite sure I understand the concept of adding an alpha channel but will give it a whirl.With out alpha channel, an image has just three channels : R, G, B. The values of these channels for a given pixel tell how red/green/blue it is. With an alpha channel (noted 'A'), the image has four channels (R,G,B,A). The value of the 'A' channel for a pixel tells how opaque it is.
RE: Brighten Portion of Image? - tspence - 08-12-2017
(08-12-2017, 04:41 PM)Ofnuts Wrote:(08-12-2017, 02:27 PM)tspence Wrote: Not quite sure I understand the concept of adding an alpha channel but will give it a whirl.With out alpha channel, an image has just three channels : R, G, B. The values of these channels for a given pixel tell how red/green/blue it is. With an alpha channel (noted 'A'), the image has four channels (R,G,B,A). The value of the 'A' channel for a pixel tells how opaque it is.
Gotcha - thanks!
RE: Brighten Portion of Image? - GMP - 10-11-2021
(08-12-2017, 01:34 PM)rich2005 Wrote: For that image, I would try:I like your method, since I can vary the amount of lightening by varying the hardness and force. I have a neck area I'd like to lighten, but the usual circle or ellipse aren't the right shape. Can I use your method after drawing a selection around the neck area? If so how?
Add a white layer on top
Put that layer into overlay mode
Add a black layer mask: Layer -> Mask -> Add Layer Mask and choose Black (full transparency)
It should look like this: http://i.imgur.com/tfbNujU.jpg same as the original.
Click in the layer mask (the black square) to make it active, it is active if it has that white border.
Change the foreground colour to white, choose the most fuzzy brush you have (probably the one shown in the screenshot)
With a large size, just click once over the head, add a couple more clicks as required.
something like this: http://i.imgur.com/bbUNwxN.jpg
When you screw it up, just fill the layer mask with black and start again
RE: Brighten Portion of Image? - sallyanne - 10-11-2021
You could also try this.
Outline the area you want to lighten with free select
, After you get to the end and you get the marching ants - feather the selection. Between 3 & 8 usually. Larger # for a larger photo and smaller # for a smaller one. Then use the curves tool which will lighten this area only. The feathering should have a blurring effect into the outer area, if not enough feathering, you can use the healing tool 
to go over the line created to bring the two area colours together.
RE: Brighten Portion of Image? - denzjos - 10-11-2021
@ tspence, my meaning is that the photo is a little under exposed. I think the photo should look more natural if the whole photo is lightened up instead of the face alone. It is a piece of cake to do this (one of the possibilities) : just copy the layer and set the layer mode from the copied layer to 'screen'. Then use the opacity slider to become the result you like.
[attachment=6843]