I am a big fan of pinup myself, and found the image that she is trying to replicate in one of my books around the house.
as I am looking at the 2 right now, the first thing I notice is about the "sultry-ness" of classic pin-up.
You did a very great job replicating the image, and I agree that the backdrop is a little distracting but what is missing most is that special "sultry" or "sexiness"
the original image by Gil does not have her skin showing, however the wardrobe is clingy (and showing her "curves" very well) and her white transluscent panties and barely noticable..just enough to make you want more. and I think the suggestion mentioned above about slightly unbuttoning the top would have been an easy way to make up for the difference (since the curvy classic model is most well endowed in the upper region.)
and the comment about the brush...is just that the brush in the updated image kinda reminds me of the one i use to wash my bathroom tub, rather than shine boots, so a rag/cloth might have made sense, unless of course you could find a brush that looks more like a boot brush (with black worn bristles, you can find at any boot store or military supply)
the guitar does create a black hole in the image. In the original Elvgren you will see that even though the guitar is backward, it is white....the same color as the background, so it doesn't cause any distraction.
Hope to see more pin-up re-makes!!
