# invert/reverse tone curve?



## mgolin (Mar 2, 2014)

I recall (which I admit is not the most reliable device) reading somewhere that there was a "trick" to reverse the curve so that the LH black point is at the top, dropping to the lower RH corner, making the white end dark, effectively making a negative.  Is there?  Thanks.


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## clee01l (Mar 2, 2014)

In the Tone curve panel, there is a small icon in the lower right corner to toggle editing points on the curve.  Toggle this "on".  The end points on the curve will appear (and others too if the curve is not linear).  Grab the left one on the bottom and drage it to the top. Repeat with the right point dragging it to the bottom.


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## Rob_Cullen (Mar 2, 2014)

Great answer Cletus-
Next, immediately create a preset with just the "tone curve" boxes selected in the preset, and you have the immediate method to convert neg-pos images.
I 'copied' 200 large B&W negatives using my DSLR & macro lens. It was easy to convert all to 'positives' as I imported the images from camera.!! with the preset in the 'Import' dialog.


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## mgolin (Mar 2, 2014)

I actually tried the grab & pull, but only in the std curve.  DUH!!!  It led to some funky results, but not what I was attempting.

Thanks for the replies, & the preset is also a great idea for importing.


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## clee01l (Mar 2, 2014)

mgolin said:


> ...the preset is also a great idea for importing.


Yes that's what makes this such a great group.  No matter how many times you can give the "right" answer, someone can come along and improve upon it.


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## dmiles1030 (Aug 3, 2019)

Hi,  I just started converting a bunch of b&w negatives into positives using the inverted curve technique.  When I run facial recognition Lightroom does not find any faces in ~800 phots I have done so far.  I went and drew rectangles around a few faces and when I switch over to the people view the photos with rectangles show up as negatives.

Does facial recognition use the un-adjusted photos or is the inverted curve confusing it   (Or more likely it is somehow confusing - me!)


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## Linwood Ferguson (Aug 7, 2019)

I had a similar experience.  Pretty much nothing works with the inverted curve the way you expect it to.  Even the inverted curve doesn't work for color negatives, at least not very well -- very hard to take the color cast off.

If you have some you want done well, take it to photoshop and invert there, and then adjust the curves to take out the color casts (if you do R, G, B separately you can just adjust the cutoffs high and low to near where the data points are). 

And if you have opportunity press Adobe.  The core problem with inversion in lightroom is that it is done late in the development process not early.  They have said occasionally they might look at an option to invert it early, then all the sliders would work correctly (and maybe facial recognition, who knows).


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## PhilBurton (Aug 7, 2019)

Ferguson said:


> I had a similar experience.  Pretty much nothing works with the inverted curve the way you expect it to.  Even the inverted curve doesn't work for color negatives, at least not very well -- very hard to take the color cast off.
> 
> If you have some you want done well, take it to photoshop and invert there, and then adjust the curves to take out the color casts (if you do R, G, B separately you can just adjust the cutoffs high and low to near where the data points are).
> 
> And if you have opportunity press Adobe.  The core problem with inversion in lightroom is that it is done late in the development process not early.  They have said occasionally they might look at an option to invert it early, then all the sliders would work correctly (and maybe facial recognition, who knows).


There are some third party alternatives for negative tone curve inversion, but I have never had a chance to try out any of them:

Negative Lab Pro  <- claims to work entirely inside LR.

CNMY film inversion < - for PS


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## Linwood Ferguson (Aug 7, 2019)

Phil I'm glad you posted that, I had not seen Negative Lab Pro.  It's quite interesting and does a fairly nice job, but it is like all the others -- once you get back into Lightroom it either (a) saves a TIFF so you have the overhead of the TIFF to carry around, or (b) the sliders are all screwed up from the inverted curve.  But they do quite a nice job of getting the initial setup right, much better than I can get by hand in lightroom.  Much.   And you can use their sliders instead.  It's quite a cool product, I'm thinking about whether it might be worth it.

But... I still think you can do better in Photoshop, unfortunately.

I really wish Adobe would allow the invert early, so the sliders work!


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## PhilBurton (Aug 8, 2019)

Ferguson said:


> Phil I'm glad you posted that, I had not seen Negative Lab Pro.  It's quite interesting and does a fairly nice job, but it is like all the others -- once you get back into Lightroom it either (a) saves a TIFF so you have the overhead of the TIFF to carry around, or (b) the sliders are all screwed up from the inverted curve.  But they do quite a nice job of getting the initial setup right, much better than I can get by hand in lightroom.  Much.   And you can use their sliders instead.  It's quite a cool product, I'm thinking about whether it might be worth it.
> 
> But... I still think you can do better in Photoshop, unfortunately.
> 
> I really wish Adobe would allow the invert early, so the sliders work!


Ferguson,

I learned about both these applications in this forum:  Scanning and Scanners

Phil


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## LouieSherwin (Aug 9, 2019)

Another great resource for how to scan all your film archive is Peter Krough's excellent eBook Digitizing Your Photos with Your Camera and Lightroom. As with all of his books he goes deep in to the details of methods and techniques for how to quickly digitize a large film archive. Includes dozens of well produced video tutorials. 

The only downside is the somewhat lame Preview on Mac OS does not allow you to link to the video tutorials so you have to use Adobe Acrobat and it took me awhile to figure out the the table of contents is in the Bookmarks section of Acrobat.

-louie


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