foreground color won't set

[ShinehahGnolaum]

When I pick a foreground color using the color picker, the color remains gray.  How do I change it to blue using the color picker?

[c.pfaffenbichler]

Could you please post a screenshot taken at View > 100% and with the pertinent Panels (Layers, Channels, Options Bar, …) visible?

Which Channel/s are selected?

[ShinehahGnolaum]

I don't understand what you mean by channels.

[c.pfaffenbichler · Accepted solution]

The image is Grayscale.

[c.pfaffenbichler]

I don't understand what you mean by channels.

In RGB-, CMYK-, Lab-images one can select individual Channels or Layer Masks instead of the composite Channel.

[Yogesh5E61]

Can't we change it?