Getting a good scan of some baseball cards is difficult due to the finish on the card. I've struggled for years with cards with a dufex finish. I have found it almost impossible to get a scan that I'm even remotely happy with. I recently discovered a trick which, while not yielding a perfect scan, yields a result I can easily live with.
I normally scan cards at a resolution of 150 dbi. I find this gives a reasonably sized file which looks good on screen, and can be printed with good results. Here is a Rookies subset card from the 1994 Upper Deck set. This subset uses the Dufex printing technology. Dufex is a form of lenticular printing which you can read about here. Using my normal scanning technology, this is what I get.It's Alex Gonzales of the Blue Jays, right? I use an Epson Stylus CX6000 and Photoshop Elements for my scanning. Although not as powerful as regular Photoshop, Elements has a lot of tools. But no matter how much fooling around I do, this is about the best I can do.
At least you can tell it's a baseball card made by Upper Deck. The scanner comes with scanning software which has a number of adjustments. I've tried a number of them before without much luck. The other day I tried again and fooled around with something called "Histogram Adjustment". There are several things you can do with this, none of which I understand. One is a sliding scale adjustment which goes from 0 to 245. Below this is a curve. I tried moving around the slider which moved the curve. By setting the slider to 90, this is what I got.
Already this looks better. What this did was dim the scanner light. This perhaps makes sense as I think the real problem with scanning these types of cards is that they are too reflective. You see the same sort of problem when you scan cards with a mirror or bright foil surface. In Photoshop Elements, I applied the Auto Level tool and got this.
Then I used Enhance:Adjust Lighting:Shadows/Highlights to Lighten Shadows at 100%. The final result:
This is a pretty good approximation of what the card actually looks like.
If you're not using an Epson scanner, or not using Photoshop, you'll have to fool around to figure out how to reproduce this. The key seems to be to dim the scanner light. I've had pretty good luck on a number of different cards which have foil logos or other printing. The foil looks much better with this technique.