Photoshop Flatten layers - Image Contrast drops

[Wyck]

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Hi,

 

I have a bit of problem that I could do with some help please.

When I take a scanned negative in to Photoshop and make adjustments and then flatten the layers I notice a drop in brightness / contrast in the Image.  

The files are tiff files that are coming from a Noritsu scanner, my workflow is the following:

I import the tiff file into PS and get a missing profile message.  I choose to assign the working RGB: Adobe RGB (1998) profile.

New layer for levels and I adjust the black / white point.

Another new layer and I adjust the curve.

I then flatten the layers and notice the contrast drops.  

I can see this clearly by using the history palette and clicking on the previous image state.

I'm a Capture One / ImagePrint user and notice the same.  I import the tiff into C1 and set levels / curve.  I then select Edit With (ImagePrint) and a duplicate tiff is created for IP,  I then notice the same drop in contrast in the image from the original that is shown in my C1 browser.  I notice the same in the image in ImagePrint.

I have tried various tiff files that have been created from different scanners - Nikon Coolscan and Fuji Frontier.  It clearly isn't PS or C1 but is it a limitation on the colour space?  I should say the negative / file is black and white.  I am using an external calibrated Eizo screen.

When I look at the original files under preview / Inspector they are RGB 

Does anyone have any ideas please?

Thanks

Gary

Edited March 23, 2021 by Wyck
To add information

[frame-it]

like this ?

https://feedback.photoshop.com/conversations/photoshop/photoshop-loosing-adjustment-effects-when-flattening/5f5f45684b561a3d4249f2b7

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[Wyck]

47 minutes ago, frame-it said:

like this ?

https://feedback.photoshop.com/conversations/photoshop/photoshop-loosing-adjustment-effects-when-flattening/5f5f45684b561a3d4249f2b7

Yes that's it.  I had looked at similar posts before posting here and tried some of the suggestions for example merge layers including background but this didn't work.  Another suggestion was 8 bit, I was already in 8 bit so tried 16 and then 8 again but the same.  The other suggestion is to work in 100% view mode but as you can appreciate this is not really an easy way to edit an image.  

I see exactly the same behaviour in Capture One so surely something else is going on here.

[adan]

28 minutes ago, Wyck said:

The other suggestion is to work in 100% view mode but as you can appreciate this is not really an easy way to edit an image.  

Well, one can alternately zoom in and out to see what's really happening. This is such a normal part of my Photoshop work that after 25 years I no longer even notice it. Double-click "magnifying glass" icon - double-click "hand" icon. In and out.

Photoshop (and I assume most image editing programs) is always "rendering" your picture to screen, using various shortcuts and tricks to simulate the changes you are making. Except at 100% view.

It is a trade-off between fast real-time editing and accurate WYSIWYG display.

Old-timer war story: Back in 1990 or thereabouts I watched Photoshop 1.0 at work on the new Mac II color computer. Superpowerful for the time. Make a change in a full-color picture, even scaled (on screen) to 1024 x 768 (XGA) - and it would take Photoshop 15 seconds per color channel to render the change (redraw blue, redraw green, redraw red).

That was the native speed with no shortcuts to speed the screen rendering. It is why Adobe soon added math shortcuts to speed the rendering of an image "shrunk" to fit your monitor.

You might check your PS preferences to see if there is a slider for "speed" vs. "accuracy."

(Dirty Little Photoshop Secret: regardless of what color mode you give an image (RGB, CMYK, Grayscale) - Photoshop always does its computing in an L*a*b* version of the image, translating that on the fly to the RGB screen pixels (at any zoom), and ultimately saving the work back into your designated mode.)

 

 

[Wyck]

Thanks Andy for your reply.

I do see what you mean you do soon get used to zooming in and out quite quickly.  I will also take a look at my Photoshop settings a little later, I did take a quick look and there is nothing obvious but I am sure there is something I can try out.  

As far as L*a*b* mode goes I recall seeing an early Monochrom CCD video, I think it was by Ming Thein and I'm sure he suggested working in this mode for all Monochrom files.

When I was 18 I worked for WordPerfect on telephone support.  WordPerfect 5.1 was the latest version of the software.  We would always be fielding calls from users who would complain about what they were seeing on screen wasn't printing correctly. They used to use the space bar to line up their documents.  WYSIWYG was just a future dream.  One day we were all called to the conference room after work for a demonstration of the latest software.  Looking back it was such a letdown but at the time we were all stunned.  It was the ability to add shapes to a document and you could even resize them on screen; the demonstration shape was the outline of an arrow.  

[zeitz]

2 hours ago, adan said:

You might check your PS preferences to see if there is a slider for "speed" vs. "accuracy."

I looked all through Preferences for this and cannot find it.  If others can find it, please let us know where it is.

2 hours ago, adan said:

Photoshop always does its computing in an L*a*b* version of the image

That is very interesting.

 

14 minutes ago, Wyck said:

he suggested working in this mode for all Monochrom files

I remember seeing long lists of steps on how to do monochrome in Lab space.  There must have been steps that I didn't understand because I could never get good results.  Channel Mixer was the method I used at that time.

16 minutes ago, Wyck said:

When I was 18 I worked for WordPerfect on telephone support.

My first experience on a PC was on a Wang for word processing.  I learned to save with great regularity because any little glitch on the Wang PC caused you to lose all your work.  Looking back now, it was so primitive.

[jaapv]

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It does sound like a colourspace mismatch. Make sure all your workflow is in the same colourspace. and only convert just before saving.

[Wyck]

6 hours ago, jaapv said:

It does sound like a colourspace mismatch. Make sure all your workflow is in the same colourspace. and only convert just before saving.

Thanks for your suggestion Jaap, I will have a good look at the weekend to see if there is a mismatch.