photo filter greyed out

[2Randy]

I have a black and white film negative scanned as jpeg and inverted to positive image.  I want to add sepia tone, but the photo filter option is greyed out in the adjusment panel.  What am I missing?

[alexfotoland]

The image must be in RGB, not in grayscale

[2Randy]

Perfect.  Many thanks

[c.pfaffenbichler]

Should @alexfotoland not have solved your issue already please post screenshots with the pertinent Panels (Toolbar, Layers, Options Bar, …) visible.