I looked at this when first posted but could not come up with a good method for a single color that can be used with BIMP
You can select-replace a colour using the gimp_gmic_qt plugin but there is an antialiasing border that does not get completely changed. Gmic shows in BIMP as other procedure. A few wrinkles in use if you need more info ask.
At the expense of a slight change over-all, this is easier. color-balance. One or the other
You can select-replace a colour using the gimp_gmic_qt plugin but there is an antialiasing border that does not get completely changed. Gmic shows in BIMP as other procedure. A few wrinkles in use if you need more info ask.
At the expense of a slight change over-all, this is easier. color-balance. One or the other