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How do I Rebuild the Red Channel?

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  #11  
Old 01-28-2006, 02:45 PM
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Cameraken Cameraken is offline
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Hi Rô.

OK. OK You got Your Five stars. Great job. You got some detail in her ear rings which I missed.

Thank You for the extra info on High Pass.

Image Invert > Gauss > Blend Mode Add.

This (if I am not mistaken) is the same as a contrast reduction. So this is similar to a balance of Shadow/Highlight. Yes?


Ken
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  #12  
Old 02-01-2006, 12:58 AM
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mistermonday mistermonday is offline
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Hi Ro, super job on the tough one. FYI, I found a way to get to your 3rd stage quickly without a mask. With the original image, duplicate the red channel as is and apply the copy to the red channel in multiply mode 100% opacity. Then apply the copy again to the modified red channel. This will get you exactly to your 2nd attachement. Next select the entire left side of the image from the separation (with a heavy feather) line down the gentleman's shirt. I took the image into LAB and with two very simple straight line curves, moved the A & B channel to get the color on the left half of the image to match. The L channel looked really nice. I attenuated the heavy yellow cast in the face with a narrowly restricted B channel curve. Finally, blurred the A & B channels to get rid of a little color noise. I stopped here since you already applied the image enhancement tricks
Regards, Murray
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File Type: jpg Red-B JimmyMJB2 Rev MM Thumb.jpg (87.3 KB, 33 views)
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  #13  
Old 02-01-2006, 08:36 AM
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Craig Walters Craig Walters is offline
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as ken pointed out, this is the easy one

this was mostly 'color balance', 'color mixer', a blank raster layer for fill here and there, and splitting out the red channel and erasing the noise rather than blurring it, then adding the channel back and tweaking it some more. i also ran a 'digital camera noise removal' and added a contrast adjustment layer.

the image is primarily a blue and green image. lots of grass and lots of sky. the oddity here is the boy's skin. but that's influenced greatly by the surrounding blues and greens and the natural shading and colors would tend to dull down the pinks and reds. so, in the color balance and color mixer steps, i pretty much removed ALL the red, except in the high tones. and that removed the color cast of the warped red channel. the rest was just in trying to get the boy's skin a bit less blue and green and sharpening and tweaking a bit.

if i were doing this for a client, however, the first thing i'd do is crop the image and get rid of that bright foreground and remove the extraneous side wasted space. this would also eliminate most of the unwanted reds which were heaviest on the sides and that alone would reduce the work and make this easier to do.

craig
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File Type: jpg Red-A-1-k-1.jpg (97.4 KB, 19 views)
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  #14  
Old 02-01-2006, 09:27 AM
dkcoats dkcoats is offline
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Wow.

This is one freakin' great thread. This is exactly one of the things I want to get better at. I've bought entire books and got less out of them than I just learned. (did that sentence make sense?)

Ro, Ken, Murray - hats off.

David
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  #15  
Old 02-01-2006, 01:54 PM
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Cameraken Cameraken is offline
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Hi David.

Thanks. Yes Rô’s steps were great and I always enjoy reading Murray’s LAB approach.

In the ‘hard one’ I got to Rô’s attachment 2 picture without a mask. I just used channel mixer
Red +46
Green -56
Blue -24

In the ‘easy one’
I had some success with apply image after Rô’s step 4.
Channel Red blend mode Multiply (Attached.)


Ken
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File Type: jpg Ken_Red-A.jpg (92.0 KB, 41 views)
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  #16  
Old 02-03-2006, 12:52 AM
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Flora Flora is offline
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... I had missed this one ....

I used two different methods to try to correct the red Channel in these pictures...

Apply image and Selective Colors for the 'easy' one ...

Duplicated background, Inverted it and adjusted Hue/Saturation and Contrast for the 'difficult' one ....

After this it's just a matter of how much or how little one wants to do ...

For the difficult one.. the couple at the bar, it's a lot of guessing .... they are obviously tanned and the lady is very tan .... now what tone does a tanned skin take is, I think, as individual as fingerprints .... orangy, reddish, golden, bronze ... you name it ....
Attached Images
File Type: jpg F_Red-A.jpg (99.3 KB, 33 views)
File Type: jpg F_Red-B.jpg (98.5 KB, 49 views)
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  #17  
Old 02-03-2006, 05:14 AM
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byRo byRo is offline
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When I grow up I want to retouch like Flora!

Just perfect (again)

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  #18  
Old 02-03-2006, 07:04 AM
Cassidy Cassidy is offline
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Flora,

Would you mind at all elaborating further? (please)
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  #19  
Old 02-03-2006, 11:37 AM
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Flora Flora is offline
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Hi,

Thanks ....
You always come out with very precious gold nuggets .... and a lot of what I do is based on tips or ideas I got from you .... One of them, for example, is the High Pass/Gaussian Blur combination .... thanks again for it!!!!!

Cass,

I'll have to split my answer because I have more than 5 Attachments ....

'Dreamy' boy in the grass:

I've always used Apply image in these cases ... probably, not better than any other Channels interacting Tool as has brilliantly shown, but I feel very comfortable with it .... But, I got this technique from somewhere in the Internet ... I can't remember where anymore so I can't give the due credit ...
Anyway it involves using the Apply Image Tool on a Layer Mask instead of on Channels or Layers directly ....
  • I duplicated the Background Layer.

  • Created a white Layer Mask for the Duplicate, and making sure I was working on the mask and not on the Layer ... (Optional>Alt+Click on the Mask so all you see is the white Mask and any change you will make on it from your Apply Image Dialog) ...

  • .... went to Image>Apply Image and, for this image, selected as in Attachment 1.

  • Applied Auto Levels on the newly created Mask. Attachment 2.

  • Sorry I had forgotten .... After the Auto levels, I lightly blurred the Mask (Radius = 1px)

  • Still working on the mask, Ctrl+Click on it to select its Luminosity and Ctrl+Shift+I to invert the selection because I wanted to correct the darker parts of the image first.

  • With the selection active, I created a first Selective Colors Adjustment Layer where I tweaked Reds, Yellows, Magentas, Whites and Neutral until I was happy with the result. (Tweak the mask if necessary to either bring some of the original colour back or to increase or decrease the strength of the Mask in different parts of the image.

  • Went back to the 'original' Mask and Ctrl+Click on it to select its Luminosity and again, with the selection active, I created a second Selective Colors Adjustment Layer where I tweaked Reds, Yellows, Magentas, Whites and Neutral until I was happy with the result. (Tweak the mask if necessary to either bring some of the original colour back or to increase or decrease the strength of the Mask in different parts of the image.
Attachment 3 shows my Layers' Palette so far ...
Attachment 4 The result I got right after these procedures ....

Not even 10 minutes work so far .... The end result depends on how much or how little you want to do after this.
Attached Images
File Type: jpg SNAP-0104.jpg (74.3 KB, 31 views)
File Type: jpg SNAP-0110.jpg (93.7 KB, 24 views)
File Type: jpg SNAP-0113.jpg (99.9 KB, 23 views)
File Type: jpg SNAP-0112.jpg (97.1 KB, 32 views)

Last edited by Flora; 02-04-2006 at 05:53 AM.
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  #20  
Old 02-03-2006, 11:42 AM
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.... Next Chapter ...

Couple at the bar:
  • I duplicated the Background Layer.

  • Ctrl+I Inverted the duplicate and set its Blending to Soft Light ...

  • Still working on the inverted Duplicate, Ctrl+U>Hue/Saturation to lightly decrease saturation and carefully increase Lightness .... This, mainly to brighten up the image in which, particularly the lady, would look rather greenish and too dark if you start immediately to correct the red leak ...this also slightly diminishes the red 'cast' which, at this stage is still quite strong...

  • Loosely selected the red areas and strongly feathered the selection.

  • With the selection active, I created a Hue/Saturation Adjustment Layer where I tweaked Reds and Yellows until I got an acceptable result... After this procedure, parts of the picture were nearly completely desaturated, so, I corrected the AL Mask to paint some colour back.

  • Ctrl+Click on the AL's Mask to reselect and created a Levels AL to improve contrast.
Attachment 1 shows my Layers' Palette so far ...
Attachment 2 The result I got right after these procedures ....

Not even 5 minutes work so far .... and again ... the end result depends on how much or how little you want to do after this.
Attached Images
File Type: jpg SNAP-0114.jpg (81.6 KB, 22 views)
File Type: jpg SNAP-0111.jpg (92.3 KB, 32 views)
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