Adjust backdrop color to specific swatch.

[Dominic Deacon]

Is it a strong colour? If the colour that you need to replace is similar to the backdrop in the photo then you should be able to just select the background with the pen, the lasso or- if your lucky- just the colour select tool and then paint over the old backdrop with the colour you want. If the backdrop is very different then your mask has to be excellent and that method is probably not worth your time but it’s a process I use on most photographs I take (even though I don’t have to hit a certain specified colour) as it just neatens up the backdrop nicely.

[Kalleheikki Kannisto]

Use a curves adjustment (layer) and adjust the individual RGB or CMYK channels to shift them from their current values to the desired value range.

Since you have an essentially flat color, the color range will show up as a peak in the color channel histogram. Select one channel at a time in the Curves dialog (R,G or B) or (C,M, Y or K) depending on your document color mode respectively. You can see the input (current) value and the output (after correction) value below the Curves adjustment graph. Click and drag the point vertically where the diagonal adjustment curve meets the horizontal center of that peak until the output value is correct.

My interface is in Finnish, but this is the basic idea (example with green channel selected):

[James Chance]

Thank you!