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Difference layer mask

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  #11  
Old 04-10-2011, 09:12 PM
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Godmother Godmother is offline
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Re: Difference layer mask

Quote:
Originally Posted by Boneappetit View Post
Tampoco yo lo encontre, decidi hacer lo que me habias recomendado y funciono... El difference mask como tal solo se puede hacer en After Effects. En Photoshop se usa el Blend Mode de otras formas, con diferentes exposiciones, o con el blur filter... Si deseas puedes ver este video, el cual encontre muy interesante... http://www.youtube.com/watch?v=zolWLMHUd94
Si, yo uso el difference para visualizar al hacer coincidir limites... no entiendo el punto de usar una mascara hecha con esa diferencia, lo que seria la "difference mask"

entendes?

x
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  #12  
Old 04-11-2011, 09:10 AM
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Boneappetit Boneappetit is offline
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Re: Difference layer mask

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Originally Posted by Godmother View Post
Si, yo uso el difference para visualizar al hacer coincidir limites... no entiendo el punto de usar una mascara hecha con esa diferencia, lo que seria la "difference mask"

entendes?

x
Solo en estos ultimos dias he venido a entender "un poco el Difference Blend Mode", pero no lo de la mascara, ya que hasta donde yo recuerdo, nunca lo habia usado en mis trabajos. Solo hice la pregunta porque en un tutrorial lei el paso del Difference Mask para crear densidad en la foto. Algo como el trabajo que hiciste de diferentes modelos parados en un solar oscuro, en donde el ambiente de la composicion se ve denso, (de paso, muy buen trabajo).

Disculpa por poner a trabajar tu mente inecesariamente, por tus consejos tambien me he dado cuenta que no hace sentido el hacer ese DM, pero tampoco entiendo porque Adobe After Effect tiene esa funcion, supongo que es porque el programa es para hacer animaciones y pienso que en ese caso si puede tener efecto.

Me gusta hacer cosas diferentes siempre y busco como hacerlas y aprender de los mejores. De todas formas, tu consejo funciona. Gracias por tu ayuda, eres genial...
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  #13  
Old 04-11-2011, 12:05 PM
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Aladdin Aladdin is offline
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Re: Difference layer mask

With due respect, can we have this in English so we all learn. Please.
@Boneappetit: If you get any thing out of this discussion, please feed us the goodies
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  #14  
Old 04-11-2011, 01:29 PM
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Boneappetit Boneappetit is offline
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Re: Difference layer mask

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Originally Posted by Aladdin View Post
With due respect, can we have this in English so we all learn. Please.
@Boneappetit: If you get any thing out of this discussion, please feed us the goodies
Hi Aladdin: My question was one out of not having knowledge on how to use the Difference Blend Mode, and I was trying to create a "difference mask" from it... Natalia and Jonas cleared that up for me... The difference blend mode, is used along with other features in Ps, like Luminosity Mask and Blur filter... besides, it is used with different exposures of the same shot. Basically i did this:
Quote:
The blending mode difference will show different things with different layers.

I guess you can always do a stamp of what you get when blending, then selecting the luminosity of the RGB channel and creating a luminosity mask of the difference blending mode results - after that you get rid of all the steps, you could create an action that does it for you. / ------

Actually it is a Luminosity mask with a Difference blend mode...

I came up with the question after I read this:
Quote:
Next make a difference mask like this…

http://www.robert-randall.com/MM/diff%20mask%201.jpg <---- Broken Link

Load it to make it active, and then ask for a layer curve. Now you can play with adding or detracting density from the midtone area to help create the illusion of more density. Usually this is a darkening move, but it can go the other way too. / ------

Perhaps Robert Randall meant something else, I don't know.
Difference mask is a feature that comes in Adobe After Effects not in Ps...
Natalia told me that she couldn't see the point on creating a mask from that difference. So that's about it...

I had to use Spanish with Natalia, so I could clearly communicate what I was trying to do...

Regards

Last edited by Boneappetit; 04-11-2011 at 10:05 PM.
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  #15  
Old 04-11-2011, 02:58 PM
julianmarsalis julianmarsalis is offline
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Re: Difference layer mask

Quote:
Originally Posted by Boneappetit View Post
Hi Aladdin: My question was one out of not having knowledge on how to use the Difference Blend Mode, and I was trying to create a "difference mask" from it... Natalia and Jonas cleared that up for me... The difference blend mode, is used along with other features in Ps, like Luminosity Mask and Blur filter... besides, it is used with different exposures of the same shot. Basically i did this:
Quote:
The blending mode difference will show different things with different layers.

I guess you can always do a stamp of what you get when blending, then selecting the luminosity of the RGB channel and creating a luminosity mask of the difference blending mode results - after that you get rid of all the steps, you could create an action that does it for you. / ------

Actually it is a Luminosity mask with a Difference blend mode...

I came up with the question after I read this:
Quote:
Next make a difference mask like this…

http://www.robert-randall.com/MM/diff%20mask%201.jpg <---- Broken Link

Load it to make it active, and then ask for a layer curve. Now you can play with adding or detracting density from the midtone area to help create the illusion of more density. Usually this is a darkening move, but it can go the other way too. / ------

Perhaps Robert Randall meant something else, I don't know.
Difference mask is a feature that comes in Adobe After Effects not in Ps...
Natalia told me that a "difference mask" makes no sense, and it really doesn't. So that's about it...

I had to use Spanish with Natalia, so I could clearly communicate what I was trying to do...

Regards
Robert Randall is a old master of photography who knows more about the subject then many peeps combined he was explaining exactly what his mask did in terms of the image and didn't cover its creation but if asked he would share maybe still would if asked. But I caveat he can be harsh but to be honest his work is pretty awesome and his knowledge of photography even moreso....

http://www.robert-randall.com/content/

Oh and I be very careful before I state something like his statement doesn't make sense be more like I don't understand how you made a or achieved a difference mask or you may get your ass handed to u lol...
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  #16  
Old 04-11-2011, 03:27 PM
julianmarsalis julianmarsalis is offline
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Re: Difference layer mask

Quote:
Originally Posted by Robert Randall
Quote:
Originally Posted by Koray
I cant believe you actually did give out how to for real haha...but if one gets past the DH look there is more valuable info there that can be used and are being used alot.

never thought of a difference mask before...gotta experiment with it
Sometimes the difference mask can be a bit abrupt in transition of tone. When that happens, you can possibly overcome the effect by blurring one of the masks in your difference calculation.
a little more insight on the mask creation calculations baby...


Quote:
Originally Posted by Robert Randall
Quote:
Originally Posted by QOL
Couple of question... how does CMYK help the colours stay in gamut? Do you keep versions of the image open in LAB and CMYK and pull channels in from those files as needed?
When you stop to think of the number of different channels available for use in blending and calculations it's mind boggling. Most people think there are 10. RGB, CMYK, LAB, GS. I can make a huge amount of different channels from an assortment of color separations, as well as fabricating HSL channels through calculations. There are quite possibly hundreds of channels to choose from in making the assorted masks you might need. And yes, I use them all.
This thread is just full of Mr. Randall dropping knowledge people can't handle lol...

http://www.modelmayhem.com/po.php?th...=304298&page=1

Last edited by julianmarsalis; 04-11-2011 at 03:33 PM.
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  #17  
Old 04-11-2011, 03:45 PM
julianmarsalis julianmarsalis is offline
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Re: Difference layer mask

Another interesting excert Mr Randall never answered but I am gonna try it myself:

Quote:
Originally Posted by digital Artform
Quote:
Originally Posted by Robert Randall
Sometimes the difference mask can be a bit abrupt in transition of tone. When that happens, you can possibly overcome the effect by blurring one of the masks in your difference calculation.
I assume you are taking a positive mask image and a negative mask image and using the Photoshop blend mode 'difference' to create these difference masks?

I played around a bit with that to see what it does. My guess is the difference blend mode turns a standard linear 45 degree rising tone curve into an inverted V-shape.

I have a suggestion that produces a soft curve into and out of the midtone difference mask.

http://www.digitalartform.com/archiv...s/outline1.jpg

http://www.digitalartform.com/archiv...s/outline2.jpg

Sometimes when I need what I think you are calling a difference mask I take a postive image and multiply it by its negative.

http://www.digitalartform.com/archiv...s/outline3.jpg

Anything that was black in either the positive or the negative goes black in the multiply, and what survives are the common grays.

http://www.digitalartform.com/archiv...s/outline4.jpg

The brightest gray is 25%, since it is the product of the 50% mid-grays in the input images, so you have to use a steep curve to crank final brightness by 400% to make it white.

http://www.digitalartform.com/archiv...ng_an_out.html

http://www.digitalartform.com/archiv...s/outline5.jpg

---------------

http://www.digitalartform.com/archiv...es/demoman.jpg

Here's my "outline" recipe in action in the movie Demolition Man (1993). I used black and white 3D turbulence to wipe this movie set from "normal" to "icy." All of the midtone gray areas in the wipe were extracted using the recipe described above and turned electric blue.
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  #18  
Old 04-11-2011, 04:04 PM
julianmarsalis julianmarsalis is offline
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Re: Difference layer mask

If its this simple someone slap me lol

If you copy one of the images to a new layer above the other,
change the mode to difference, duplicate the image, flatten layers and desaturate, this should give you a map of the difference between the images, where black is no difference,
that you can then use as a mask.
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  #19  
Old 04-11-2011, 04:32 PM
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mistermonday mistermonday is offline
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Re: Difference layer mask

Quote:
Originally Posted by julianmarsalis View Post
If its this simple someone slap me lol

If you copy one of the images to a new layer above the other,
change the mode to difference, duplicate the image, flatten layers and desaturate, this should give you a map of the difference between the images, where black is no difference,
that you can then use as a mask.
Yes, that would work but wouldn't it be more efficient to just create a merge all layer and select the luminosity and hit the Create mask button?
Regards, Murray
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  #20  
Old 04-11-2011, 05:37 PM
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Boneappetit Boneappetit is offline
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Re: Difference layer mask

Quote:
Originally Posted by julianmarsalis View Post
Robert Randall is a old master of photography who knows more about the subject then many peeps combined he was explaining exactly what his mask did in terms of the image and didn't cover its creation but if asked he would share maybe still would if asked. But I caveat he can be harsh but to be honest his work is pretty awesome and his knowledge of photography even moreso....

http://www.robert-randall.com/content/

Oh and I be very careful before I state something like his statement doesn't make sense be more like I don't understand how you made a or achieved a difference mask or you may get your ass handed to u lol...
Hi Julian: There is no doubt in my mind that Mr. Randall is a super pro. But if you do a search on the internet about "Difference Mask in Photoshop" you won't find even a dot of info. not even on the Adobe page, and BTW that's why I asked. The only reference I've seen so far, is his own tutorial (the one you posted) but that link is dead, because he closed his MM account... I just said that "maybe he meant something else", I don't know...

Just want to clarify, I didn't say Robert Randall doesn't make any sense. For me and my very limited knowledge of Ps, it doesn't make sense, it is just not the purpose of the "D Blending Mode". I even wrote the question for him, then I changed my mind and didn't send it, because I thought, he won't bother to answer... So, if you find a tutorial on how to do it, please share it...

Correction: What Natalia told me was that she didn't see the point in doing a mask from Difference, the comment "makes no sense" is mine, reason written above. <---- bear in mind that Spanish is our main language...

Last edited by Boneappetit; 04-11-2011 at 05:43 PM.
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