In a Levels adjustment, selecting Gray changes color format of the image

[walt.farrell]

1. Start with an RGB image.
2. Add a default Levels adjustment. It will show the format setting (for the adjustment) as RGB and the image is not changed.
   
    
3. Switch to CMYK or LAB, and the image remains unchanged, though of course the histogram changes:
   
    
4. However, switch the adjustment to Gray and the image is changed to grayscale, even though no slider adjustments are made:
   

[carl123]

8 minutes ago, walt.farrell said:

2. Add a default Curves adjustment.

I think you mean Levels adjustment

[walt.farrell]

38 minutes ago, carl123 said:

I think you mean Levels adjustment

Duh. Of course; Sorry, and fixed. Thanks.

[NotMyFault]

Just my 2 cents: I would rate this as a feature, not a bug. It simply includes an BW adjustment with defined weights for RGB channels.

Normally you are using the levels adjustment to actually change the levels, and use the rendering to visually check the resulting effect to the document. I think it is technically and functionally required to show the rendering converted to grayscale.

If you want to work on RGB channels and stay with RGB, using the RGB / CMYK levels adjustment could be the better option.