If you scroll down on that Perchance page there are prompt suggestions to help users including better resolution, though I find 'improve image quality' works. For some grainy low-res images (like screencaps from old videos) the AI image can still sometimes retain the graininess (or some of it) or odd colour balance for reasons unknown.
I try and keep it very basic. I DM'd this to another forum member the other day. The wording in the quotes is all I add to the prompt.
1) Basic colouring prompt "improve the image quality, change to colour"
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2) Alterations to the original. If there is something in the original you don't like or it's unclear (so needs a prompt). You can use a prompt like "improve the image quality, change to colour. Change the hair of the female on the right to brown with a ponytail".
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Or, for other variations "improve the image quality, change to colour. Change the stockings of the female on the right to white knee socks. Change the face of the man on the left to a mature man, he is smiling, he is looking down at her bottom". It often needs to be told where people are looking and their expressions, you can also try without these extra prompts and it will sometimes work. With this one his Hitler moustache looks idiotic (IMO!) hence the change.
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If I didn't like some of the hairstyles or faces in the original images I would amend. You can change the colour of the clothes, even what they're wearing. Some images are better for this than others. Plus the 'new' faces it adds can start to begin to look like the same "sad female" over and over again, it seems to get them from the same source. You can also change the background though the scale is often wrong and if it does work this often gives the image a bland AI look to it.
I did try and 'improve' some of those Room 2d images but the results weren't really any better. 'Crying' frequently produces the watery nonsense. As you can see the colour could be improved but that may require further prompts.
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