Sprites change when transforming

Hello,

I am creating a 3d game, but I have imported some images and set them as sprites. Now I have realized that “change their look” depending on what position they have in the 3d world. You can see it in the following image. How do I prevent this?

Edit: I figured out that it must have to do with the Directional Light. But I still cant figure out how to change it.

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It is unclear what you’re asking here. The only issue I see on the image you posted is letters being slightly blurry.