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Curve of a curve of a curve...

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  #21  
Old 04-14-2015, 11:17 AM
Doug Nelson's Avatar
Doug Nelson Doug Nelson is offline
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Re: Curve of a curve of a curve...

John:

So the inverse curve point to 64,32 would not be 64,96 but rather 32,64?

Using this curve gives similarly changed results.
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  #22  
Old 04-14-2015, 11:17 AM
skoobey skoobey is offline
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Re: Curve of a curve of a curve...

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Originally Posted by AKMac View Post
And I also had the impression that after multiple adjustment layers were merged, the histogram ended up looking a lot healthier than it did when the calculations were only pending.
It's the simplicity that makes it so predictable and easy to use.

Quote:
Originally Posted by AKMac View Post
And I also had the impression that after multiple adjustment layers were merged, the histogram ended up looking a lot healthier than it did when the calculations were only pending.
If you merge them in order they are stacked, things should be exactly the same(there is a histogram button to make it more precise(I believe it's the triangle within the histogram preview itself).

Quote:
Originally Posted by Doug Nelson View Post
Aren't curves absolute mappings? Input value is changed directly to an output value? (again, theoretical curves)
Yes, but it's a curve, like the name says, results are based on parabolas and hyperbolas, it's in percentages, not absolute values.
What you are talking about exists and it's brightness adjustment. Curves are not linear, they are curves. You can do this with curves tool by making a straight curve moving only the end points along the edges.

Last edited by skoobey; 04-14-2015 at 11:26 AM.
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  #23  
Old 04-14-2015, 11:24 AM
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Re: Curve of a curve of a curve...

My brain hurts.

But somewhere in here I think we've established adjustment layers are revertible but not lossless.
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  #24  
Old 04-14-2015, 11:26 AM
skoobey skoobey is offline
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Re: Curve of a curve of a curve...

Hahaha. I'll do a video.
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  #25  
Old 04-14-2015, 11:27 AM
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Re: Curve of a curve of a curve...

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My brain hurts.
Well stop banging it against that table!
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  #26  
Old 04-14-2015, 11:43 AM
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Re: Curve of a curve of a curve...

So unless someone can come up with a valid counterargument, I think we've succeeded in invalidating thousands of internet tutorials, Youtube videos, and every 10-step/24-hour/Quik/Dummies book out there. Not bad for a day's work.

And I will endeavor to stop using the term "non-destructive" in all future RP LIVE shows.

It shall be known as a shibboleth, along with blurred skin, screen DPI, and sRGB, to differentiate the US from the THEM
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  #27  
Old 04-14-2015, 11:44 AM
skoobey skoobey is offline
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Re: Curve of a curve of a curve...

Yeah, the term is reversible.

Another one that drives me freaking nuts, but everyone including me is accustomed to it is "texture". It's texture when it's 3d, it can only be detail when in an image, but I guess it can be used when referring to a subject in the image, BUT NOT THE IMAGE ITSELF. Image has no texture, that person in it might wear a sweater with great texture.
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  #28  
Old 04-14-2015, 11:49 AM
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Re: Curve of a curve of a curve...

Quote:
Originally Posted by Doug Nelson View Post
John:

So the inverse curve point to 64,32 would not be 64,96 but rather 32,64?

Using this curve gives similarly changed results.
That is correct Doug. Here is a none banging head on table way of thinking about it when you look at a single pixel value.

If you have a pixel of value 64 (with you above example), it would be turned into a value of 32

To reverse that process:

Now, with a value of 32 for that pixel, you need a Curves adjustment Layer where the line goes through input = 32 and output = 64 to turn it back to 64.

So yes, the inverse of input=64 output=32
would be
input=32 output=64

Does that make sense. If not, an ice pack might help

However, I should not that the Curves Adjustment Layer is using splines. And if you just take the spline points and try and mirror those points, it does not create an inverse for the whole curve. That is one of the reasons I mentioned that creating an inverse curve is not that easy in PS.

You can get closer using the pencil tool and drawing straight lines (holding shift key) to get pretty good inverses e.g.

The good curve with its inverse is shown below:
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File Type: png Screen Shot 2015-04-14 at 10.45.49 AM.png (21.5 KB, 5 views)
File Type: png Screen Shot 2015-04-14 at 10.46.19 AM.png (21.9 KB, 6 views)
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  #29  
Old 04-14-2015, 11:53 AM
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Re: Curve of a curve of a curve...

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Originally Posted by skoobey View Post
It's texture when it's 3d, it can only be detail when in an image
By that logic images can't have shadows, either. That way madness lies.
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  #30  
Old 04-14-2015, 11:58 AM
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Re: Curve of a curve of a curve...

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Originally Posted by Doug Nelson View Post
And I will endeavor to stop using the term "non-destructive" in all future RP LIVE shows.
I agree with Andrew that getting everyone to agree on nomenclature is impossible.

I for one stick with non-destructive when I can go back and reverse or modify adjustments that I made including recovering back to the original image. LR and ACR are better than PS at this yet you can do pretty good just with PS.

I see all the other discussions as degradation which occurs in all programs including Lightroom and ACR, just less than PS. With good knowledge of how the programs work, you can take steps to minimize the degradation or stay oblivious to the details and stick with 16 bit.

All IMHO or course.
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