If I omit a detail in a description that is known by the character but unknown by the reader because of circumstance, should I worry about it? Example: My MC knows the color of something because he's seen it before. When the MC encounters the thing during the story, it's too dark to know the color. I feel weird describing the color even though it's too dark to tell even though color is something that is often described. My instinct is to not worry about the color, but what are the common ways to deal with details such as this?
It's perfectly fine not to mention his knows what color it is. Let's say your character is a police officer and he nee a green colored form but accidently receives a yellow one. Reader would just assume a form is a form until the narration or dialogue indicated a sudden issue as the character realizes the error. If it's too dark to tell color, it'd be more than normal for the character to try and make out the color despite the lack of coloring or that he'd hope/pray it's a certain one.
It depends if a particular identification is important to the story. If not, then the MC can "know" whatever it is simply because he has prior knowledge of it. If it is critical, say a clue, then bringing it up later without mentioning that the MC knew it before hand and how, may make the reader feel cheated.
I think it depends on why you'd be mentioning the color, or why you'd mention it if there were light. If it's for distinguishing between things, you'd probably distinguish between them using some characteristic that's perceptible in the current situation: Light: He opened the box of kittens and grabbed the solid black one, ignoring the marmalade and tiger-stripe. Little light: He opened the box of kittens and peered at their barely visible shapes. After a moment, he grabbed the roundest one. If it's a permanent identifier that is essentially the thing's name, you might leave it unchanged: Light: The President grabbed the red phone. Little light: The President grabbed the red phone. If it's for atmosphere, I'd switch to something that's perceptible: Light: He walked into the room and blinked at the blood-red walls and bright pink ruffled curtains. Little light: He walked into the room and bumped into two chairs and a table covered in jangling china before he'd gone six feet. For a moment he thought that the windows were guarded by large furry creatures, but as he edged closer he realized that it was ruffled curtains. If it's a "sneak it in there" description that's there for no particular reason, I'd lose it: Light, pre-rewrite: She pushed her red hair back from her pale face as she peered at the book. Rewrite, light or no light: She pushed her hair back as she peered at the book.
You can probably use something else to explain the details later. For example, your MC knows the color, but his partner (assuming he has one) does not and asks about it. I do things like that all the time, and come back to explain it later in some way.
Well he would be eating it in the next few sentences. It's color isn't important but since people don't generally know what a "mudbug" looks like I feel strange not using something so prominent in its description. "Inside the cage a couple mudbugs flopped around. They were about the size of his hand and had two long pincers outstretched from a plump/stout (whatever FU!) thorax. Its tail was short and segmented and flared out at the end. Dryden reached down and pried apart a narrow gap at the top of the cage and pulled out one of the mudbugs by its antennae." A mudbug is slang for a crayfish.
Hmmm. Now that you've given us the actual quote from your story, the dilemma is a bit clearer. If it were me writing this, I wouldn't pull out of the story to describe the mudbug at all. I would work the description into the action—see below. However, if you're going to keep your format the way it is, why NOT put in the colour too? "...had two blue pincers outstretched from a fat yellow thorax. Its short red tail was segemented, and it flared out at the end." However, you could just work the description into the action, which might work better. Inside the cage a couple of mudbugs flopped around. Dryden reached down and pried apart a narrow gap at the top of the cage and pulled out one of the mudbugs by its antennae. The mudbug tried to sink its pincers into Dryden's hand, so he shifted his grip to the creature's back instead of the antennae. At that angle, his hand was safe from the waving blue pincers, but the mudbug's segmented yellow body whipped and coiled, its flat red tail fanning and closing as it struggled to get away. Dryden had to keep his grip tight while he closed the cage with his other hand. I'd sneak in the description without taking time out to tell us what the creature looked like. That way we not only don't 'stop' to read the description—which might as well be an informational footnote at the bottom of the page if it breaks the story flow—but it also gives us the impression that Dryden is familiar with the creature.
If the character wouldn't notice the detail at that time, don;t bring it up from that character's POV. If the character sees his bald friend, and the friend is no more or less bald than other times the charcter has seen him or her, don't bringit up (unless the character has a habit of ribbing his gleaming friend about the glare). If it's important to the story, on the other hand, then you need to find an unobtrusive way to bring it up:
While I really need this time to slow down the pace I do want to parallel this experience to him being in a similar situation as the mudbug in the middle(ish) of the chapter. As I think about it, however, it feels unimaginative and contrived (not your writing, but implementing the parallel through action). My original expression of this situation was to simply express it through dialogue to the mudbug. I need to have him talking to things that don't talk back because of an important part of his character development. Who knows though, my mood shifts and I may go with it.
Well, I was just riffing on the idea as I saw it from what you'd given us. Your idea sounds intriguing ...having him talking to the mudbug? That might work well. I think what I was trying to get across was how to avoid an infodump in the middle of an action sequence. He's approaching a cage. Then there's a bit of a dump about what's inside it and what it looks like (in some detail, even without the colour.) And then he opens the cage. And, as you say, he would already know what this creature looks like ...so however you present this to the reader, it's best to incorporate the description into the action, if possible. Having him 'talk' to the mudbug (including references to its looks ...'don't curl your red tail at me, bubba...!' might be a really interesting way to approach the scene.
I'm going to weave in the description while also paralleling the similar situation during the dialogue. It's going to have the whole feel like a kid playing with his food, which is exactly what's happening.
First draft with the changes. It looks like I didn't need to mention the color at all. "Dryden reached down and pried apart a narrow gap at the top of the cage and reached in to grab it. The mudbug quickly popped its short segmented tail beneath it and bounced around the cage evading his grasp. There was no escape; the mudbug’s portly thorax was too large to squeeze through the gaps in the cage. Dryden waited for it to stop then reached back in. Instead of attempting to flee, it held high its two stout pincers and twitched its anatine furiously. Not wanting to get pinched, he snuck his other hand behind the mudbug while distracting it with his other. He chuckled, the irony not lost on him, and snatched up the mudbug by its thorax behind the pincers. A row of tiny legs rippled feebly against the empty air. “Well, little guy,” he said to the mudbug. “If you can manage to impale my skull with a sharp rock, I’ll give you this one.” With that, he held the mudbug’s pinchers together and bit down on its head. The juices inside gushed out and dribbled down his chin. He grinded the chitin and internal organs into tiny bits between his teeth and then swallowed. It tasted bland, much like everything he ate, but that’s not what he like about eating. It was the texture, especially things that were crunchy. “Looks like I won.”"
I love 'portly' in this context, it works well. Word 'pinched' is somehow jarring here, it doesn't agree well with the preceding 'pincers' and 'twiched'. Maybe 'nipped' would flow better. This feels like narrator's comment. It's better to describe him laughing at the irony, even say 'Laughing at the irony of it all, he snatched...' etc.
