Using a desat w/ color change to create a sepia antique style image is fine............

http://www.renderosity.com/mod/gallery/index.php?image_id=1617924

Here I changed an all grayscale render to sepia and added a presentation style.

I didn't paste a clip art or photographic Biker dude, Or make flames all around it with
PS-brushes........just basic postwork.

Read the comment with the image.

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Ockham's razor- It's that simple