These kinds of color notes are usual for Egmont stories. But they are not intended to be printed in comics like this, but used internally by colorists and translators.
Here's another example from the copy translators use:
In The Don Rosa Library edition of The Universal Solvent, the colorist mistakenly thought that the upper part of Gyro's trousers were his shirt. The only problem is that his shirt is the same color as his skin, resulting in the final panel looking like Gyro has his pants pulled down. Below is a comparison between the original correctly colored WDCS 606 printing and the incorrectly colored Don Rosa Library printing:
I don't understand how this slipped by both the colorist and editor. It doesn't take more than a quick glance to notice that something is off here. Then again, characters not wearing pants is nothing new in Duck-comics.
In The Don Rosa Library edition of The Universal Solvent, the colorist mistakenly thought that the upper part of Gyro's trousers were his shirt. The only problem is that his shirt is the same color as his skin, resulting in the final panel looking like Gyro has his pants pulled down. Below is a comparison between the original correctly colored WDCS 606 printing and the incorrectly colored Don Rosa Library printing:
I don't understand how this slipped by both the colorist and editor. It doesn't take more than a quick glance to notice that something is off here. Then again, characters not wearing pants is nothing new in Duck-comics.
That color change seems to have been introduced earlier, in Uncle Scrooge 401. The coloring in my copy is functionally identical to the DRL panel you posted. However, the only color credits in the issue refer to the cover, not the story.
In The Don Rosa Library edition of The Universal Solvent, the colorist mistakenly thought that the upper part of Gyro's trousers were his shirt. The only problem is that his shirt is the same color as his skin, resulting in the final panel looking like Gyro has his pants pulled down.
Well, looking at all those wrinkles/folds, maybe he does?