My design teacher in Chicago said logos need to work in one color, and he was right
Back in 2019 I made a logo for a coffee shop that only looked good in full color with a gradient. My teacher at the time said to always test it in solid black first before showing the client anything. I ignored him because the gradient looked cool on my screen. When the owner tried to embroider it on aprons, the whole thing turned into a gray blob. Now I sketch every logo in one color before touching the palette, and it has saved me from at least three bad client moments. Does anyone else still forget to test print their work in black and white?
Notice you said you sketch in one color now, but what about the actual shape itself when it gets shrunk down to something tiny? I ran into that with a bakery logo last year where the little wheat stalk detail looked fine at full size but turned into a fuzzy speck once we put it on a 1 inch sticker. Do you test your one color version at small sizes too, like scaled way down, or is the black and white test mostly about checking contrast and not losing forms? Seems like those are two different problems and I keep messing up the small size one.