Do-it-yourself channel mixer in PE4.

[PulkownikSwiatlo]

I am in the process of making the 'do-it-yourself' monochrome channel mixer in PE 4. I am almost there, but one last piece is missing. I am hoping to get some help :)
Well, first step I figured out. I need to create three layers of the image: gray-from-red, gray-from-blue and gray-from-green.
That is very easily doable, even without any plugins. For example to make the 'gray-from-red' layer you do this:
1. Make the fill adjustment layer, fill it with color RGB(255,0.0) and set the mode to 'Multiply'. This will make a version of the image in the red channel.
Why 'Multiply'? Simple mathematics: in Multiply you multiply colors, so the multiply of RGB(255,0,0) with any color RGB(r,g,b) will give you RGB(r,0,0). Simple!
2. Merge the layer with it's adjustment and desaturate the result.
3. That is our 'gray-from-red' image. It should be exactly the same as the ones from the plugins, because every pixel from the original picture with a value of RGB(r,g,b) should be transformed to a value of RGB(r,r,r).
4. After repeating the same steps for blue and green we should have three gray layers: gray-from-red, gray-from-blue and gray-from-green.

The last step I still can't figure out. I need to find a way to merge those three layers into one, where from each layers I use only a certain percentage,
remembering of course that those percentages need to add up to 100.
If I know how to do this, then we will have our monochrome channel mixer in PE 4 without a need of any plugin.
Any help please?
Thanks
Cezar

[TonyW]

Cezar: It certainly should be possible to make your own but if you want to see one in action for PSE4 you can get one from Richard Lynch's site - I believe the free tool set he discusses in the following post is still available there:

http://www.photoshopelementsuser.com/forum/showpost.php?p=137397&postcount=1

Tony

[PulkownikSwiatlo]

Cezar: It certainly should be possible to make your own but if you want to see one in action for PSE4 you can get one from Richard Lynch's site - I believe the free tool set he discusses in the following post is still available there:

Tony

Thank you! I will certainly download those tools.
However, for the sake of my own satisfaction in learning I would like to find a plugin-free solution to my problem, which is combining layers into one with user defined percentage contribution of each layer.

[TonyW]

Cezar: I figured that was what you wanted to do and it's by far the best way to learn some of the tricks. But I also learn a lot by looking at how other people have done it - those tools are actions that automate a series of steps that get you to the end result - although some access hidden features as I recall the Channel Mixer uses things you can do in PSE4 to isolate the RGB channels and then lets you pick the percentages to remix them in.

Tony

[PulkownikSwiatlo]

Cezar: I figured that was what you wanted to do and it's by far the best way to learn some of the tricks. But I also learn a lot by looking at how other people have done it - those tools are actions that automate a series of steps that get you to the end result - although some access hidden features as I recall the Channel Mixer uses things you can do in PSE4 to isolate the RGB channels and then lets you pick the percentages to remix them in.
Tony

That's the thing! I figured out how to isolate RGB channels, but I don't know how to remix them with percentages.
What would actually help is the knowledge of the mathematical formulas used by the blending modes.

[Byron Gale]

...What would actually help is the knowledge of the mathematical formulas used by the blending modes...Cezar,

HERE (http://www.pegtop.net/delphi/articles/blendmodes/intro.htm) is something about that... I asked Google for "photoshop blending modes formula".

I am interested in your results!!

Byron

[PulkownikSwiatlo]

Cezar,

HERE (http://www.pegtop.net/delphi/articles/blendmodes/intro.htm) is something about that... I asked Google for "photoshop blending modes formula".

I am interested in your results!!

Byron

Incredibly phenomenal link!
Many of those modes are not available in PE, so the solution may be available only in PS, which has already the channel mixer included. I guess Adobe doesn't want to make it easy...$$$$

[Wendy]

Ummm ...

I haven't come across some of those modes ??? ... not in Elements OR Photoshop :confused: :confused:

Wendy

[Benny Pedersen]

I also plan to create ALL the alpha mixer stuff for PSE4 so Im very interested in this topic. It toke me some time to make a new test file for testing the different blending modes, etc. so I didn't wrote much code today but below is a new TestWheel.psd that we can use for those experiments :)

BadScreenShot.jpg
http://hjem.get2net.dk/b_pedersen/tut/BadScreenShot.jpg

Benny,
Final Conclusion: Jump to page 2, #16 (http://www.photoshopelementsuser.com/forum/showthread.php?p=187251#post187251)

[PulkownikSwiatlo]

There is an interesting article:
http://www.earthboundlight.com/phototips/photoshop-elements-curves.html

It looks that in PE versions 1, 2 and 3 it was possible to do most of the actions that PS was doing, so the users could "cheat" PE by making all the plugins and making PE almost as functional as PS for 4 times as little money.
Then maybe Adobe realized that it is not making enough cash and released version 4 in which all the little hooks were removed so that people are forced to pay big bucks if they want advanced features.
So it looks that PE 4 is nothing more but a marketing move....

[Benny Pedersen]

There is an interesting article:
http://www.earthboundlight.com/phototips/photoshop-elements-curves.html

It looks that in PE versions 1, 2 and 3 it was possible to do most of the actions that PS was doing, so the users could "cheat" PE by making all the plugins and making PE almost as functional as PS for 4 times as little money.
Then maybe Adobe realized that it is not making enough cash and released version 4 in which all the little hooks were removed so that people are forced to pay big bucks if they want advanced features.
So it looks that PE 4 is nothing more but a marketing move....

That would be very stupid so I thought it was a bug in PSE4.
PS and PSE are good programs that I use but they are not precise in adjustments, etc... just try some gradient work or try
paste an image into a mask and then see the histogram... :eek:
The professional people are using other programs than Adobe so if stuff were removed from Elements, then we would get something even less usefull.

Benny,
PS: I think Adobe should release a bug fix for PSE4.
Also they should remove both CMYK and all profiles other than RGB and 8 bit.
Anyway, none would be able to see the difference between 8 and 16 bit...
- Instead the Adobe Circus could improve PSE and maybe lower the price....

[PulkownikSwiatlo]

I wonder if this solution would work:
Let's do the steps I described in the lead post, i.e. let's make three layers: gray-from-red (named Gred), gray-from-green (Ggreen) and gray-from-blue (Gblue).
Let's stack them up: Gred on top, Ggreen in the middle and Gblue on bottom.
Set the opacity of the Gblue to 100%, so the gray-from-blue layer sits on the bottom on full opacity.
Now we need to manipulate the opacities of Gred and Ggreen.
We know that if we apply opacity (op) to a blend layer, then the resulting image will have the form = op*blend+(1-op)*base.
So if set the opacity to Gred to Ored and opacity of Ggreen to Ogreen, then the final image will have the form:
Ored*Red + (1-Ored)*(Ogreen*Green + (1-Ogreen)*Blue) =
Ored*Red + ((1-Ored)*Ogreen)*Green + ((1-Ored)*(1-Ogreen))*Blue.
Thus if we want the final contribution of Red to be set to Cred, and green and blue to Cgreen and Cblue, then our opacities should be equal:
Ored = Cred
Ogreen = Cgreen / (1-Cred)

That's it!
The opacity in these calculations are in range (0-1), so everything must be multiplied by 100.
So the final formulas are:
Ored = Cred
Ogreen = Cgreen * 100 / (100-Cred)

For example imagine that our requested contribution of channels is R=20%, G=70% and B=10%, then the layer opacities must be set to:
Opacity(red) = 20%
Opacity(green) = 70*100/(100-20) = 87%

I tried it on several cases and it seemed to work, but I guess in needs a better tester...
Can I ask for a favor? What are the typical channel percentage contributions in some typical situations, like portraits or landscapes?

[TonyW]

There is an interesting article:
http://www.earthboundlight.com/phototips/photoshop-elements-curves.html

It looks that in PE versions 1, 2 and 3 it was possible to do most of the actions that PS was doing, so the users could "cheat" PE by making all the plugins and making PE almost as functional as PS for 4 times as little money.

Fortunately most got put back in PSE5 making PSE4 something of an anomaly. PS curves and channel mixer do work in PSE5 - but not in PSE4. To be fair though there is a big difference in functionality between all PSE versions and PS. Once you add a PS curve or a channel mixer layer in PSE you can't go back and adjust it. That is a big limitation if you're trying to fine tune an image.

Tony

[Benny Pedersen]

PulkownikSwiatlo:
To use identical stuff for testing I would like to know how you made the
gred. Was it multiply blend above red #FF0000 and then Ctrl+U -100 saturation ?

I have another app so I could figure out the typical channel percentage, etc., but Im going out visit a friend this evening.

Benny

[PulkownikSwiatlo]

PulkownikSwiatlo:
To use identical stuff for testing I would like to know how you made the
gred. Was it multiply blend above red #FF0000 and then Ctrl+U -100 saturation ?


Yes, exactly. I take the original image, make a solid fill layer set to Multiply and filled with FF0000, and then -100 saturation.
The same with ggreen and gblue (00FF00 and 0000FF correspondingly).

Interesting fact is that if you want to make equal contribution, then the top layer must be at 33% opacity and the middle at 50%.
I guess this is how the PS channel mixer works. All the contributions are set equal, but the slider bar is regulating the brightness of the color channels.
So our hand-made mixer is more flexible because we can change not only the brightness of particular channels, but also their overall contribution.
In addition to that we have a visual representation of each channel, and that is allowing us to know exactly what is happening at each channel so we can make an appropriate action on it.

[Benny Pedersen]

Thanks for good work.

I will now take a closer look and compare the results with all the others (Free hidden and the one from earthboundlight.com - My plan was to do such compare work anyway so I have the earthboundlight installed for many days ago. I will download from others and compare all the versions.

Agree - The do it your self and adjust the opacity is simply the way to it! I don't like actions that flatten all the layers, etc... :D

Grab the test image: http://www.photoshopelementsuser.com/forum/showthread.php?p=187007#post187007
Final Conclusion: http://www.photoshopelementsuser.com/forum/showthread.php?p=187457&posted=1#post187457

Benny

[Richard Lynch]

I've already done all this and spell out the means of the process in my books, and provide the channel mixer as a free tool for Elements 4 (and I have it ready for 5--I just need to update my website). If you understand separation, it should be skipping stones on a pond to actually mix the channels. It is not as simple as using opacity alone, and the free tool answers the question as to what modes to use. Channel mixer swings both ways in that you can ADD and SUBTRACT channel components. the latter can be useful for such things as infrared effects. This channel mixer can also do more than the Photoshop one which is limited to particular modes and no more than 200%.

I would go on to say it is not Elements that has limitations, but the mindset of Photoshop users who whould never need to do many of the core activities Elements users do to understand images. I used Photoshop for about 10 years before even looking at Elements, and I learned a lot more from Elements BECAUSE all of the numbing tools were not there. I can do CMYK separations from scratch (and show how in the book), and Photoshop users will rarely have an understanding of that beyond choosing a mode.

There is something to be said for struggling with an idea...and it may help you learn. But I've already done all the basics (and then some). Use what is already done to expand ;-) Don't go howling when Adobe changes or removes stuff...find a better way. My hidden power books are all about that.

[PulkownikSwiatlo]

..My hidden power books are all about that.

I am looking forward to buying your book on PE 5 as soon as it comes out.
Thanks
Cezar

[Benny Pedersen]

Action download,
Post no 23 in thread: Advanced Elements > Advanced B&W conversion, Here (http://www.photoshopelementsuser.com/forum/showthread.php?p=187561#post187561)

Benny