Lincoln scared me when I first watched the episode as a kid. I don't know if it was intentional or just bad makeup, but I noticed that Lincoln started to age and deteriorate toward the end with dark circles under his eyes and highlighted furrows and creases in his face. I thought I even noticed a green tinge (perhaps it was my TV at the time). I was expecting that he was slowly transforming into his natural lava creature appearance.
It's definitely not one of my favorite episodes and I haven't watched it in years. I'll have to take another look to see if I was imagining things or did Lincoln actually start to degrade as I imagined? if I'm right and he did, I'm wondering if it was intentional or was it due to just bad make-up.
Sorry if this has been brought up before ... I tried to search and got a lot of Lincoln hits, but nothing specifically addressing this.
Watched the ep just last night, and with your comments in mind.
Indeed, in a few of the extreme close-up shots on the planet, Lincoln's complexion was darker, even off-color a bit, and the make-up seemingly applied in a manner that over-accented the actor's age-lines.
However, in the medium and wide shots Lincoln's appearance is usually more "normal", if you will ... skin tone more realistic, make-up less dramatic.
I chalk this up to the extreme close-up shots (Lincoln's face and nothing else) in question possibly being re-takes with the make-up and lighting different than when the scene was originally shot. Of course, the worst was during his "... four bloodiest years ..." line so maybe there was some intention to the difference in the make-up.
Also, at the moment Kirk, Spock and Lincoln first hear "Surak's" cries for help, the shot is an extreme close-up of Lincoln and plainly in slo-motion as he turns his head. Being an editor, it appears to me that there wasn't an adequate initial-reaction shot from Kirk and Spock, but yet I didn't really see a need to resort to that to technique, it could have been done using another shot like the wide of the landscape they use moments later.