I get asked quite often how I get such perfect black backgrounds in my fish and full tank shot photographs, and whether my tank is painted. None of my tanks are painted because I don't like the permanent aspect, regardless of quality. I'm no paint expert but from what I gathered from researching the painting of the tanks, the best results are after applying a preparation product such as Penetrol or ESP, which may affect the glass if you ever decided to remove the paint.
Since beginning in the hobby I've always had black backgrounds on advice of a friend who taught me this method. I'm sure its documented elsewhere, but here's my method that may be slightly different.
What you need:
- Appropriate size of Blue/Black Double sided background vinyl (I call it vinyl)
- Canola Oil Spray
- Something flat and square, like a plastic scraper, ruler, etc.
- Black electrical tape
- Old Newspaper
This is pretty much what I use.
a) Wipe down the background of your aquarium with a half wet fine cloth and allow to dry. Methylated spirits will also work but I generally have other things going on when applying a background that I can attend to in the meantime. Don't dry it with a towel as you'll leave tiny specs of hairs and such on the glass, so unless you want to go over it again with a static brush or similiar I suggest waiting it out.
b) Cut your vinyl backing to fit onto only the glass sections of your tank, so it's not overlapping any corner edging, it needs to go on perfectly flat. Don't be overly pedantic about making it absolutely perfect, as we have methods of smoothing out the edges once it's applied. If your tanks over 24" high or you bought backing that's too short and need to join pieces together, that's fine. Cut everything to fit neatly even if there are gaps.
c) Lay some old newspaper out on the floor and lay your vinyl down with the colour you want to see facing upwards. Grab your Canola oil, and go to town on it. You don't need a whole lot, but a decent coating like you were doing a thin undercoat using spraypaint will be enough.
d) Carefully lift it (a friend helps here) and place onto the back (you never know) of the tank as evenly as possible, and line it up. Make sure there are no kinks or anything in the vinyl, but airbubbles are fine. Now would be a good time to whack your fluro setup on top of the tank and flick them on. If you can see through any of the background on the edges grab your electrical tape and very carefully tape over any gaps. I basically just run electrical tape down both edges of the tank, and along any joinings of vinyl.
The top and bottom won't matter so much because your substrate will cover the bottom, and the top will generally be out of sight anyway.
It should probably look like this.
e) Now you're going to want to get rid of these evil air bubbles. This is where you employ your nice flat object, and a friend also helps here as he can be your air bubble spotter.
You want to locate air bubbles and push them out the top or the bottom (not where you have electrical tape) of the vinyl to let the canola oil fin in any gaps and become an even glue like substance that holds the background on. This is quite a tedious process and will take you a good 10 minutes.
This is not me in the photograph ladies, settle down.
f) Once you're happy with the results, you're done. Fill her up and you'll have a tank almost as good as mine are. Here's what the tank should look like without any water in it in comparison to the first photograph.
...and here's what the tanks and photographs should look like if you've got a DSLR, a steady hand, and some nice lighting. Once you've had black (as your aquarium background) you'll never go back.
Edit: Here's a shot of the tank currently, this is 15 months after the background was applied.
There's a few little air bubbles creeping in but they're only visible from certain angles, so 15 months on and still looking good so it's a fairly permanent solution until you decide to change it.
Hope this helps some of you out there.