Feature request: convert levels to curves

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Gimp has a feature that I found quite handy (when I was using Gimp, before I switched to Photoshop).  The feature allows the user to convert a Levels adjustment to a Curves adjustment.  

Use case: You're working in Levels and decide the 5 levels parameters aren't quite doing what you want.  But you don't want to repeat the setup in Curves.  Just press a button and Curves comes up (replacing Levels) with the five Levels parameters already set.  

Here's how the user interface looks in Gimp.


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John Isner

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Posted 2 years ago

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Cristen Gillespie

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I rarely use Levels, but I can see the point. It does sound handy.
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Michel BRETECHER, Champion

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Same for me. Good suggestion.
I don't use curves very much. The reason is that I do use black to white gradient maps adjustment layers in luminosity mode instead of curves. An old habit from the time Elements did not offer curves.
In your case, I simply add an adjustment layer and create as many tabs as necessary. That works exactly like curves, only with a different visual interface.
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JEA

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Maybe of interest to some is that in photoshop 5 and 5.5 one could save out gradients as AMP (arbitrary map) files and open them in the Curves dialog.

Gave the same effect as using a Gradient Map adjustment layer, which photoshop didn't have then.


If anyone has photoshop 5 or 5.5, just select the Gradient Tool, click on Edit, edit your gradient and then press Ctrl or Command while clicking on Save and that saves the gradient as an AMP file that can be open in curves by using the Load button and even opens in modern versions of photoshop curves dialog like cc 2017.
(Edited)
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Cristen Gillespie

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I just started in PS 5, and I heard about arbitrary maps, but wasn't even close to understanding what they were or why they used them. It does indeed tell us the close connection to the two. My PS5 was for Windows, so alas, I can't reinstall to try it just for ducks.
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Jaroslav Bereza

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Check this script: http://www.tonton-pixel.com/blog/scripts/creative-scripts/combine-adjustment-layers/
Sounds like it can do what you want and even more.
(this website runs only sometimes... depends if he has PC turned on) :-D
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Cristen Gillespie

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Yup, it does only run sometimes. Not now.
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John Isner

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I have been using that script and it does what I want.  However it creates the Curves adjustment layer in a new document.   Then you need to copy the adjustment layer back into the original document, replacing the Levels adjustment layer.  Gimp does it all in one click.
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Cristen Gillespie

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> The reason is that I do use black to white gradient maps adjustment layers in luminosity mode instead of curves. An old habit from the time Elements did not offer curves.>

What a clever workaround. I started using Curves when I got PS5 and haven't looked back, but I just had to try it out. It sounded like more effort than Curves, and after trying it, you would have to be awfully used to the technique, I think, to prefer it over Curves, but it certainly does work.

I felt — once again, and even more acutely — a limitation to the Gradient Map, and that's when you're constructing the gradient, you can't toggle the preview (or the Layer's eyeball) to compare it to the original. The Gradient Editor is still a model dialog, despite Adjustment layers becoming non modal. <sigh> I think it probably helps to slow down the adoption of the Gradient Map as the powerful tone and color enhancer it is.
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Michel BRETECHER, Champion

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I felt — once again, and even more acutely — a limitation to the Gradient Map, and that's when you're constructing the gradient, you can't toggle the preview (or the Layer's eyeball) to compare it to the original. The Gradient Editor is still a model dialog, despite Adjustment layers becoming non modal. <sigh> I think it probably helps to slow down the adoption of the Gradient Map as the powerful tone and color enhancer it is.
Yes. The workaround is to use the File > Duplicate command before adding the adjustment layer and to tile both windows. Other advantages in Elements : it's an adjustment layer and you can save as many gradients as you want. The way 'color' curves are implemented in Elements is good for pedagogy, but too limited. No adjustment layer, no access to channels (only in Levels), no saving your settings.
So, mastering gradient map adjustment layers is worth the trouble!
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Cristen Gillespie

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You're a very inventive user. I didn't realise that PSE  Curves weren't the same as in PS.  I'm going to have to point my PSE friends to your technique.  I myself will remember next time to duplicate my file and tile before opening Gradient Map.