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How to reduce the red color on image ? - Printable Version

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How to reduce the red color on image ? - Stephen Liu - 07-19-2022

Hi all,


Please advise which feature of GIMP I need to apply for reducing the red color on the photo.  Please refer to attached image.

It is an old faded photo with yellowish color.  I scanned it on my mobile phone, Samsung Galaxy S22 Ultra, macro lens 1x.

The positive photo was then cropped on GIMP and exported as .jpg file without any post-editing done.

Thanks

Regards


RE: How to reduce the red color on image ? - PixLab - 07-19-2022

Other than the usual channel mixer, color balance, curves (my favorite), and so...

[attachment=8332]

There is an extremely simple way that I already spoke in one of your thread...
Sample something supposed to be white or even "light" gray, then see the screenshot below

[attachment=8333]

Once your colored layer is set, just play with opacity and hue-saturation to fine tune.


RE: How to reduce the red color on image ? - Stephen Liu - 07-19-2022

[attachment=8334]
(07-19-2022, 04:07 PM)PixLab Wrote: Other than the usual channel mixer, color balance, curves (my favorite), and so...



There is an extremely simple way that I already spoke in one of your thread...
Sample something supposed to be white or even "light" gray, then see the screenshot below



Once your colored layer is set, just play with opacity and hue-saturation to fine tune.
Thanks for your advice.

Performed following steps;

Select "Color Picker" -> click the wall

Pls refer to screenshot_image-1

But I couldn't start the "Symmetry Painting" screen ?

Regards


RE: How to reduce the red color on image ? - david - 07-19-2022

An alternative approach: Duplicate layer. On this layer go to Filters/Blur/Pixelize. Pixelize to the maximum dimension of the image. Colour/Invert and change the mode to Overlay.


[attachment=8336]


RE: How to reduce the red color on image ? - PixLab - 07-20-2022

(07-19-2022, 04:52 PM)Stephen Liu Wrote: Thanks for your advice.

Performed following steps;

Select "Color Picker" -> click the wall

Pls refer to screenshot_image-1

But I couldn't start the "Symmetry Painting" screen ?

Regards

Huh  I don't use nor speak about the Symmetry Painting in this example (just look at the active tab/dialog in my screenshot which are the layers' dialog and the tool options)

Let's try a step by step:
In the layer's stack/dialog you have only your picture ➤ No other layers at this stage.

➤ Click on the Color picker tool(NO window/dialog will open, that's normal)
➤ In the tool options of the color picker, set it to Set foreground color (first screenshot below)
➤ then pick the color on the wall (NO window/dialog will open, this action will ONLY set the foreground color of the FG/BG icon just below the tools ➤ see second screenshot)
[attachment=8337]

➤ your new foreground color is set (see screenshot just below)
➤ now create a new layer (be sure it is selected)
➤ then use that new foreground color to fill the new layer (by directly drag n drop that FG icon on the new layer, or use the bucket fill tool, or in the menu Edit/Fill with FG color),
[attachment=8338]

➤ then put that new colored layer in grain extract mode... basically that's all you have to do
[attachment=8339]

Optional: once it's done, fine tune as explained at the bottom of my previous post


RE: How to reduce the red color on image ? - Stephen Liu - 07-20-2022

[attachment=8341]
(07-20-2022, 02:01 AM)PixLab Wrote:
(07-19-2022, 04:52 PM)Stephen Liu Wrote: Thanks for your advice.

Performed following steps;

Select "Color Picker" -> click the wall

Pls refer to screenshot_image-1

But I couldn't start the "Symmetry Painting" screen ?

Regards

Huh  I don't use nor speak about the Symmetry Painting in this example (just look at the active tab/dialog in my screenshot which are the layers' dialog and the tool options)

Let's try a step by step:
In the layer's stack/dialog you have only your picture ➤ No other layers at this stage.

➤ Click on the Color picker tool(NO window/dialog will open, that's normal)
➤ In the tool options of the color picker, set it to Set foreground color (first screenshot below)
➤ then pick the color on the wall (NO window/dialog will open, this action will ONLY set the foreground color of the FG/BG icon just below the tools ➤ see second screenshot)


➤ your new foreground color is set (see screenshot just below)
➤ now create a new layer (be sure it is selected)
➤ then use that new foreground color to fill the new layer (by directly drag n drop that FG icon on the new layer, or use the bucket fill tool, or in the menu Edit/Fill with FG color),


➤ then put that new colored layer in grain extract mode... basically that's all you have to do


Optional: once it's done, fine tune as explained at the bottom of my previous post
Hi,

Something strange on the GIMP running here.  I couldn't reproduce what you have advised.

Clicking the wall with Color Picker tool is without response.

Pls refer to images upload


What I meant "Symmetry Painting" is the screen of the image upload on your post #2.  Pls refer to the image upload. 

I have spent more than half hour without result.

Regards


RE: How to reduce the red color on image ? - PixLab - 07-20-2022

OM....
With all the explanations, me, myself I would have tried, at least, blindly the step by step EVEN if I see nothing happening, up to the very end to see if the method is working or to validate it, and NOT STOPPING at the first step because I don't understand the tool yet... (although I thought I gave you some explanations in the "step by step" on my previous post, but anyway and in case of... ➤ more about the color picker ➤ https://docs.gimp.org/2.10/en/gimp-tool-color-picker.html )

(07-20-2022, 03:56 AM)Stephen Liu Wrote: Something strange on the GIMP running here.  I couldn't reproduce what you have advised.

Clicking the wall with Color Picker tool is without response.

Pls refer to images upload

You did got a responseColor Picker did change the FG on your GIMP see the screenshot of your screenshot. But you did not pay attention...

➤ now use this color to fill the new layer
[attachment=8343]

Please go back to my previous post and do the step by step ➤ up to the very end without stopping in the middle

Understanding might possibly (maybe) come later.


(07-20-2022, 03:56 AM)Stephen Liu Wrote: What I meant "Symmetry Painting" is the screen of the image upload on your post #2.  Pls refer to the image upload. 

I have spent more than half hour without result.

Regards

Don't look at my GIMP setup, it's my GIMP, just look at what I am speaking about in my explanations, thus look only at the layers stack and tool options in this thread Wink


RE: How to reduce the red color on image ? - Stephen Liu - 07-20-2022

(07-19-2022, 06:10 PM)david Wrote: An alternative approach: Duplicate layer. On this layer go to Filters/Blur/Pixelize. Pixelize to the maximum dimension of the image. Colour/Invert and change the mode to Overlay.

Thanks for your advice.

Filters -> Blur -> Pixelize

Pixelize the whole image
Pls refer to attached screenshot

Colors -> Invert

Mode - Overlay

Pls refer to attached screenshot

Regards


RE: How to reduce the red color on image ? - denzjos - 07-20-2022

A one-click solution for this : G'Mic-Qt / Colors / Auto Balance (or 'Color Balance')
[attachment=8346]


RE: How to reduce the red color on image ? - Stephen Liu - 07-20-2022

[attachment=8347]
(07-20-2022, 04:14 AM)PixLab Wrote: OM....
With all the explanations, me, myself I would have tried, at least, blindly the step by step EVEN if I see nothing happening, up to the very end to see if the method is working or to validate it, and NOT STOPPING at the first step because I don't understand the tool yet... (although I thought I gave you some explanations in the "step by step" on my previous post, but anyway and in case of... ➤ more about the color picker ➤ https://docs.gimp.org/2.10/en/gimp-tool-color-picker.html )

(07-20-2022, 03:56 AM)Stephen Liu Wrote: Something strange on the GIMP running here.  I couldn't reproduce what you have advised.

Clicking the wall with Color Picker tool is without response.

Pls refer to images upload

You did got a responseColor Picker did change the FG on your GIMP see the screenshot of your screenshot. But you did not pay attention...

➤ now use this color to fill the new layer

"Set foreground color" already selected.

Clinking the "Color Picker" starts "Change Foreground Color" screen.  Pls refer to screenshot

Regards

[attachment=8348]
(07-20-2022, 06:18 AM)denzjos Wrote: A one-click solution for this : G'Mic-Qt / Colors / Auto Balance (or 'Color Balance')
Sorry, I couldn't find here
Colors -> Auto Balance

To restore faded photo I always try;

Colors -> Auto -> White Balance

OR

Colors -> Levels -> Auto Input Levels

I have tried "Auto Input Levels" before starting this thread.  Pls refers to image upload.

The white wall becomes a red wall.

Those solutions are NOT ALWAYS working

Regards