Single Rainbow and Double Rainbow Foils
YouTube Source: Tutorial on SR vs DR foils
Back when Gateway released, Score Entertainment bridged the changing foil types to each other. The Single Rainbow foil, or flat foil as it was referred to in the past, was used throughout Ghost Files and Dark Tournament.
This Single Rainbow foil encompassed the following:
Ghost Files Starter Deck foils
Ghost Files Tournament Rare foils
Dark Tournament Common & Rare foils
Gateway Common & Rare foils (except Team Leader foils)
Gateway Team Bonus foil inserts
Gateway Promos
Gateway League Set
But the bridge came in Gateway, as stated above. In addition to all the Common & Rare foils you pulled from Gateway boxes, some cards were Double Rainbow foils, or chrome foils as I have seen it called in the past. Double Rainbow foils came in ~4 per box. You would get 2 Commons, 1 Rare, and 1 Team Bonus insert that was Double Rainbow foil. If you buy a box of Gateway but don't know what Double Rainbow foils are, the best place to look is the Team Bonus inserts.
From here on, the Double Rainbow foil encompassed the following:
Gateway Common & Rare foils (except Team Leader foils)
Gateway Team Bonus foil inserts
Gateway Promos (some, not all)
Gateway League Set
Gateway Tournament set (1 of the 4 foil types)
Exile Common & Rare foils
Betrayal Common & Rare foils
Alliance ALL foils
So what exactly is the difference between the 2 foil types? That is the reason you are reading this. right?
1) The Foil Pattern:
If you are to hold a Single Rainbow foil (SR from now on) against the light, you will see that the card is foil, but nothing really special about it.
If you are to hold a Double Rainbow foil (DR from now on) against the light, you will see that the card has a foil pattern created running vertically on the card. Additionally, the foil will run into the black edge of the card if held right.
Picture Example:
In the above, if you look at Clash of Champions (bottom most card), you will see the foil pattern running vertically on the card (middle left), thus proving it is a DR. Take a look at the Shigure from Betrayal, you will also see it on him as well. Now, let's compare Seiryu, in the top row, who reflects so...plainly. No foil pattern running vertically, thus proving it is a SR. Same thing with all the other Dark Tournament foils. The same is true for Kazuya's Pistol and Humans on the Hunt (I won't mention Abduction b/c it's too much in the dark to tell). No 2nd foil running vertically. You will also notice that the edge of Clash of Champions is red on top and blue on the bottom. This is because the edge is foiled which is only found on Double Rainbow foils!!! If the black edge is foil, it is indeed Double Rainbow!
2) The Squares/Grid-like Format:
DR foils have small squares making up a grid-like format where SR foils do not. If you examine the card closely, you will see.
Single Rainbow Foil:
Double Rainbow Foil:
Now, you should see in the 2nd image rather clearly that there is indeed some kind of pattern going on. Although it's not clear in the scan, those dots are making up squares, or a grid-like pattern, on the card. This is the best way to tell the difference between the 2 foil types.
Recommended places to check for the squares/grid-like pattern:
If the card has a silver edge, that is the BEST place to check.
Anywhere there is white. This includes Spirit Energy cost of the card.
Any greens or reds or oranges are also great places to look for these.
I do NOT recommend looking at any place that is black. You will NOT see them. You will still, however, see the vertical rainbow foil pattern if held correctly in the light as the edges are foiled only on Double Rainbow foils.
Q: Wait wait wait, not all Promos from Gateway have a DR foil?
A: No longer correct. It's assumed they were printed as P1, P2, and P3 all have DR printings, and it is assumed they were printed on the same sheet as the other promos. Not all have been "found" yet though. As it stands, the following have NOT yet been found:
X1 Ura-Otoko
SK1 Yusuke, Raizen's Successor
R2 Counter Strike
TP2 Meditation
Q: How easy is it to get the known DR foils?
A: That ranges. X0 Kuwabara, Noble Champion is a box topper, so he is pretty easy to get. P2 Crazy World is a little bit harder, but not too bad. P3 Head-On Assault is a challenge. I have only ever seen 5 in my life. I currently own 3, used to own another but traded it to a friend for a SR copy to help him out many years ago before we knew the rarity of it. The League set isn't too bad now as more have popped up. I own 4 DR sets myself. The P1 Hiei, Determined Warrior Double Rainbow is hands down the toughest to find and is "confirmed" to be 1 of a kind, for now.