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IHP related question.

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  #31  
Old 08-22-2011, 05:43 AM
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Der_W Der_W is offline
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Re: IHP related question.

S is the original brightness value of the bottom pixel, C is the brightness value of the pixel on the top layer and R is the result of the equation.
He's just giving you the formula for the "Linear Light" mode.

The method he shows using curves for contrast matching isn't perfect though for what it's worth because one of the problems with high pass is that applying the high pass is nothing but subtracting the Original image from a Gaussian blurred version of it using an offset of 128.
That means that if the difference between the blurred image and the original is >= 128, you'll lose details because that'll be clipped.

I've uploaded a very extreme and highly not everyday example of it that shows what I mean (note that while this is not an everyday example, it's entirely possible to have this problem in your own images, e.g. in catchlights).

(O is the original layer, WZ is the blurred layer, High Pass the high pass layer, remove contrast is the contrast curve he uses. I used Smart Objects all the way so you can verify what I say :-)).

The Apply Image technique on the other hand divides the contrast beforehand, therefore making this clipping impossible, that's why it works better in those situations :-).

The file is too large to upload here, so I uploaded it to my Dropbox: http://dl.dropbox.com/u/7124285/Fore...t%20Curves.psd
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  #32  
Old 08-22-2011, 08:57 PM
adtechniques adtechniques is offline
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Re: IHP related question.

Thks Der W for your clear explanation. Where I can find the formula for other blend mode? I'm interested in it

Last edited by adtechniques; 08-23-2011 at 10:12 PM.
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  #33  
Old 08-23-2011, 02:56 AM
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Der_W Der_W is offline
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Re: IHP related question.

This should be what you're looking for: http://www.simpelfilter.de/en/basics/mixmods.html

Also Adobe has a PDF in which they explain some of the blending modes (it's better at explaining the HS* modes): http://wwwimages.adobe.com/www.adobe...32000_2008.pdf (you'll want to check the PDF at around p. 320).
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  #34  
Old 08-23-2011, 10:25 PM
adtechniques adtechniques is offline
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Re: IHP related question.

Thank you. Surprisingly, so far, I do not think it was created by the formula.
I'm still learning how to use layer supportting like in your video, I searched and found this book is consistent with what I wanna learn. Do you know the name of the book?
I think I will understand about Hue, saturation, luminance when reading it. Here some pic from: http://4chanarchive.org/brchive/dspl...+Thread+239003
And here some PrntScr of this book:

http://4chanarchive.org/images/ic/83...9892833311.jpg
http://4chanarchive.org/images/ic/83...005071821s.jpg
http://4chanarchive.org/images/ic/83...0005117886.jpg
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  #35  
Old 08-24-2011, 03:39 AM
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Der_W Der_W is offline
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Re: IHP related question.

What do you mean by "I don't think it was created by the formula"?

The book seems great :-).

Painting books are a very nice way to understand (applied) color theory, so this might be a great read for you :-).

Unfortunately I don't know the title of this book (are you sure, it is a book? I think I remember having seen this image on another graphics board and it was done by a student. I could be wrong though!).
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  #36  
Old 08-24-2011, 04:08 AM
adtechniques adtechniques is offline
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Re: IHP related question.

I mean, I've never known that before. I do not think the blend mode is created by mathematical formulas. It made ​​me surprised
I not sure it is a book or not. I saw it when I find information on color theory in
http://conceptart.org/forums
http://4chanarchive.org

it seems clearly and understandable to me
I like that way that you understand and manage color theory. You and some others here and MM are the people I'd love to learn.
Thks so much.
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  #37  
Old 08-24-2011, 05:58 AM
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Der_W Der_W is offline
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Re: IHP related question.

What else could blend modes be created of :-)?
Basically everything inside Photoshop is pure math, be it curves, a path, color profiles etc. :-).
It's a thing of beauty :-)!
Adobe just does its best to hide all the math from you so that you don't have to deal with it if you don't want to.
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