Colour Replacement Tool Works Incorrectly

[Mummblingme]

With foreground colour set to white, the Colour Replacement Tool changes the red area to grey. The Brush tool paints in white as it should. Changing the foreground to a light aqua allows the Brush to paint the correct colour, but the CRT paints to a darker version of the aqua. My goal is to have the CRT change these red areas to white. What am I doing wrong?

Many thanks for guidance.

macOS Sonoma version 14.6
Affinity Photo 2   version 2.5.3

[h_d]

15 hours ago, Mummblingme said:

What am I doing wrong?

...not quite understanding how the CRT works. 😉

From the Help:

Quote

The targeted colour's hue will be replaced with the current Foreground colour's hue, while retaining saturation and lightness values of the original pixels.

In your first example (white on red) the white foreground colour has no hue, so the hue is removed from the red leaving just its saturation and lightness values (ie grey). The same thing will happen if you set the foreground colour to black. The tool needs a foreground colour, not an 'absence of colour', to work as intended.

In your second example (aqua on red) the red has slightly varying hues, and the CRT is picking up only those values that match the point where you first click. You may get closer results to your intention if you check Sample continuously in the context menu bar, or adjust the Tolerance level:

(TBH though I reckon the CRT is a bit of a blunt instrument, and if you want to change the colour of the red brushstroke while leaving the white background unchanged, you would have more control applying an HSL Shift Adjustment to the red area.)

 

Edited August 2, 2024 by h_d
rewording

[Mummblingme]

Thank you, h_d. I see I have much to learn. Time for nose to the grindstone. I appreciate your patience and guidance.