Levels in 32-Bit Mode

New Here ,
Jun 20, 2022 Jun 20, 2022

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Hello. I am working with negative film scanned as a positive linear file. The file is assigned a linear colour profile and opened in 32-bit mode. It seems that in this mode I can invert it without any logarithmic alterations so that the file remains identical in reverse. Please correct me if I am wrong! My question is about using the Levels adjustment in 32-Bit mode. I can't decide if a non-linear transformation is being introduced. Any help with this would be great. 

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Adobe Community Professional ,
Jun 20, 2022 Jun 20, 2022

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No matter the bit depth, it should be an inverse (linear) conversion. IOW, even in 8-bit per color, 0 becomes 255, 1 becomes 254, etc.


Author “Color Management for Photographers" & "Photoshop CC Color Management/pluralsight"

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New Here ,
Jun 20, 2022 Jun 20, 2022

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Thanks very much for the reply. I need to look at that again!

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New Here ,
Jun 22, 2022 Jun 22, 2022

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Thanks for this helpful information. Very much out of my depth here, but keen to set up a good method if I can work it out. I see now that the bit depth is not a factor for inversion in Photoshop. Moving on from that, I'm thinking that to avoid introducing an inappropriate gamma curve it would be easiest to keep my file in a linear color profile until it is reversed, and then apply the gamma curve as needed.  Not 100% sure this is right, though.  As well, the visual data is mostly in one half of the scale, and I am seeking to stretch it to the full range in an evenly-spaced way without making any other change. Any advice/suggestions would be much appreciated.

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Adobe Community Professional ,
Jun 22, 2022 Jun 22, 2022

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In color managed applications, and consideration of the final output, I have no ideas as to why a linear or gamma-corrected working space would have any bearing on editing your data in Photoshop. 


Author “Color Management for Photographers" & "Photoshop CC Color Management/pluralsight"

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New Here ,
Jun 22, 2022 Jun 22, 2022

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Well, I was hoping I would be able to use Photoshop to do this in a couple of easy steps, that is keep the linear file as it is but in reverse, and to create another linear file from this, stretching the image across the full tonal range, but with no other adjustments taking place. 

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Adobe Community Professional ,
Jun 22, 2022 Jun 22, 2022

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You can keep linear data. Until you need to print or leave Photoshop for example, posting to the web in sRGB. 

The main question becomes what benefits of this linear color space from a scanner do you get before such conversions?


Author “Color Management for Photographers" & "Photoshop CC Color Management/pluralsight"

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New Here ,
Jun 22, 2022 Jun 22, 2022

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I'm hoping to make and retain for reference a linear file showing a positive view of the picture. This is to make life easier for me and others who may wish to access, assess and process the file now and in the future. If adjustments are introducd, it wouldn't be an archival record, and so there would still be a need to return to the negative scan to see the first state captured image.

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