Bug in Sketch functions in PS3 & PS2 thanks to Replace Color function

Watch your Foreground/Background colors at the bottom of the Toolbox when you’re sampling in the Replace Color dialogue (or when sampling in the image itself). See how it turns color to match the color you’re sampling?

Try this:

• Open your image.
• Tap the "D" key on your keyboard to return the Foreground & Background colors in your Toolbox to their default black & white, respectively.
• Call up the Replace Color dialogue.
• Move your Eyedropper cursor so it’s over the main image window. • Let loose of your mouse with your hand so it doesn’t move. • Carefully click to sample, but don’t move the mouse.
• Tap your keyboard’s TAB key 3 times–the numerical entry box for the Lightness slider will be highlighted.
• Hold Shift and tap your Up arrow key.
• See how the Foreground Color box in your Toolbox changes? • Carefully click your mouse button again to sample exactly where you did before. • See how the Foreground Color box in your Toolbox changes again? • The numerical field for your Lightness slider should still be highlighted. • Ignoring the Shift key, now, tap your keyboard’s Down arrow once, then your Up arrow once. • Notice the change in your Toolbox’s Foreground color again.

I’m not sure how I might use that behavior of the "Changing Foreground Color Box" to my advantage, but that seems to be the way it works. Since it happens every time, I’m not sure I’d call this a bug. Rather, I’d scratch my head and wonder: "What’s the reason it does that? What did the engineers have in mind for us…how is this changed Foreground color supposed to be employed?"

OK…now that we’ve observed what’s happening in the "Replace Color" dialogue, and how it affects the Foreground Color box, let’s consider the Sketch Filters.

The Sketch Filters you mentioned as appearing not to work (my findings: Bas Relief, Charcoal, Graphic Pen, Halftone Pattern, Photocopy, Plaster, Reticulation, Stamp, & Torn Edges) do their work by calling both the Foreground and Background colors you have set in your Toolbox. If they are the same color—in this example they are both white—all you will see is white. Like painting with bright white ink on a bright white piece of paper, there’s simply no real contrast to create an image. The other Sketch filters that do work under the White/White F.G./B.G. conditions (my findings: Chalk & Charcoal, Chrome, Conté Crayon, Note Paper, Water Paper) seem to get their lightness values a different way. How? I’m not sure.

Sooooo…It’s not that anything gets from the Replace Color dialogue gets loaded into the Sketch Filters…it’s just that the Sketch Filters get their color from the F.G./B.G. colors that are set. Which brings us back around to the same question:

Of what use is that behavior in the Replace Color dialogue, in that it sends values to the Foreground Color box in your Toolbox?

There might be a good reason, but I sure haven’t found one.

The fix for the workflow you’ve described?

After exiting the Replace Color dialogue, tap your keyboard’s "D" key to return your F.G./B.G. colors to their default Black/White.