A place to seek advice and answers on those particularly challenging issues.
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The following exercise is to show the power of shortcuts.
The result will be a greyscale representation of the green channel in your image.

- Ctrl L - opens Levels dialog
- Ctrl 1 - selects red channel
Change manually output from 255 to zero.
niv.jpg
niv.jpg (50.88 KiB) Viewed 1971 times

- Ctrl 3 - selects blue channel
same as above, output to zero
- Shift Ctrl U - Remove color
- Shift Ctrl L - auto levels

There you are. This works also in 16 bits.
Explanation: with the levels adjustment, you turn off the red and blue channel, leaving green.
Then you desaturate and the auto levels distributes the tones in the full black to white range.

If you are not convinced, add a green solid fill adjustment layer in multiply mode: you get your green channel back. Of course, you can use Graffi's or Hiddenelements tools to do just that, but knowing the shortcuts may be very helpful!
Michel B
PSE6, 11,12,13.1 - LR 5.7 Windows 7 64 - OneOne Photo Perfect Suite - Canon 20D, Pana TZ6 - Fuji X100S
Most used add-ons: Elements+


Mes Galeries
Tx Michael. I've noticed different methods of achieving the result often work better depending on the image. So the more ways to do something the better.
ljameso1 wrote: Tx Michael. I've noticed different methods of achieving the result often work better depending on the image. So the more ways to do something the better.


Very true.
It's always better to master different techniques.
Some may lead to exactly the same result. In this case using layers properties will be equivalent... Using gradient map to convert the color channel instead of desaturating plus auto levels will be slightly different.
Even if the result is the same, you may prefer the levels procedure which can work n 16 bits, or the layers one which can be saved into 3 adjustment layers you can save in a separate PSD and drag over your file:
1 - add a R,G or B solid color fill adjustment layer in multiply mode
2 - add a hue/sat adjustment layer with sat -100
3 - add a levels adjustment layer with the right input slider moved left from 255 to 128
You can select the 3 adjustment layers from the PSD and move them over your new file.

With B&W conversions, I have tested about 10 ways, some are equivalent, other are not, which may be better depending on the image...
Michel B
PSE6, 11,12,13.1 - LR 5.7 Windows 7 64 - OneOne Photo Perfect Suite - Canon 20D, Pana TZ6 - Fuji X100S
Most used add-ons: Elements+


Mes Galeries
Michel,
I tried your shortcut/color extraction technique and ended up with a really snappy black and white photo. Thanks for the tip.
Chas
Chas's Gallery
f/16 on a sunny day.....:)
Chas,
This is what we learn by experimenting: the green channel is very often an excellent way to convert to black and white. The reason is that our vision is best in the green channel. You may have noticed that the Bayer pattern of our digital sensors is based on 2 green pixels for one in red and blue. Thus less noise and more detail...
Each channel may have its own advantage. Red can be used in lighten or screen mode to enhance skin in portraits. Blue, although often noisy or blotchy, can retain details which can be used to give back texture to otherwise clipped channels (with saturated colours in flowers, for example).
One of the main use of channels is creating masks based on colour contrast between a channel and the complementary colour.
Michel B
PSE6, 11,12,13.1 - LR 5.7 Windows 7 64 - OneOne Photo Perfect Suite - Canon 20D, Pana TZ6 - Fuji X100S
Most used add-ons: Elements+


Mes Galeries
I have one-click tools that will do this. The Elements 5 tools are available on my website: http://hiddenelements.com. The Elements 6 tools can be had by sending me an email -- I'll have them on the site soon: thebookdoc@aol.com

Please use the subject: PCE Elements 6.0 Tools

I'd like to gage interest.
Richard_Lynch wrote: I have one-click tools that will do this. The Elements 5 tools are available on my website: http://hiddenelements.com. The Elements 6 tools can be had by sending me an email -- I'll have them on the site soon: thebookdoc@aol.com

Please use the subject: PCE Elements 6.0 Tools

I'd like to gage interest.


Richard,
It's a pleasure to see you here!
Back to the original topic, extracting channels. As I said earlier, there are many ways to do this, some are equivalent, others are nearly equivalent... Which is best? the ultimate criteria is that you can recombine channels to get back the original image, as you explain in your books. (If not, it may be enough for masking or other edits). I did not disclose your workflow, but there is still some mystery in your free tool!
For Elements users, the question is: why does a greyscale layer in normal mode over the background have no effect on the background (no change in color for the image) ?
The color component layer is a greyscale, you can verify it by toggling off all other layers.

Two questions:
1) how is this possible in Elements?
2) what are the advantages?

I have a few ideas about this (blend if...), but I'd like some comments about the benefits of this channel extraction mode. (There are Photoshop users here also).
Side comments, if you duplicate the channel component layer in Elements, it keeps its blending property.

Thanks in advance!
Michel B
PSE6, 11,12,13.1 - LR 5.7 Windows 7 64 - OneOne Photo Perfect Suite - Canon 20D, Pana TZ6 - Fuji X100S
Most used add-ons: Elements+


Mes Galeries
Mitchel:
His visit is what you may call a doctor visit. :lol:
Shalom,
Don
A well conseived image is a poem written with light.
PSE6 - Lightroom - CS3 - Win-Vista -Epson 7800
Nikon D80 - D-700 - Canon G9
http://www.condeimaging.com
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