Christian J
New member
That should work fine. Only reason my box is a little higher is because there was no ready-made box with the exact same measurements as my testing tank.
My Shadowbox Background Project
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My Shadowbox
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Christian J
New member
Nice! Looks like real corals in the shadowbox, is that correct?
olemos
Premium Member
Very nice:beer:
Christian J
New member
There might be a small difference. If the box light can be mounted higher above the water surface, you'll get a weaker light gradient in the box. The difference is more noticeable in photographs than to the naked eye.
A stronger light right at the aquarium's water surface may resemble the ocean surface more, while a more uniform light may resemble deeper water. Which you prefer is a matter of taste, I guess.
Christian J
New member
Now I've finally done some tests with RGB LEDs in my test box. I mounted two LED strips in parallell at the top of the box (power consumption: less than 5W?). Main tank light was an 80W mercury lamp just above the water surface, like before.
Blue LEDs at max level:
Blue and green LEDs, both at max level:
Weaker blue LEDs, green LEDs still at max level:
Green LEDs only, at max level:
In the last picture you can see how the green LED light passing through the blue acrylic is too dim to match the main tank light, except at the top. Instead the mercury lamp lights up the acrylic sheet from the front side, revealing its true color (blue) and ruining much of the "infinite ocean" effect. You can also see more mirroring in the glass. With a weaker main tank light (such as in some fresh water tanks) it might still work fine, though.
Otherwise if you like a cyan/greenish background box it's probably best to begin with a similar acrylic color. RGB LEDs can be used for fine-tuning, but they can't do miracles if the acrylic color is too mis-matched to begin with. Red LEDs are useless with a blue acrylic sheet, since the acrylic filters out red light anyway, so if you want to save money you might try dimmable blue LEDs only. White LEDs will appear like a combination of blue and green, since almost all the red is filtered out by the blue acrylic.
Blue LEDs at max level:
Blue and green LEDs, both at max level:
Weaker blue LEDs, green LEDs still at max level:
Green LEDs only, at max level:
In the last picture you can see how the green LED light passing through the blue acrylic is too dim to match the main tank light, except at the top. Instead the mercury lamp lights up the acrylic sheet from the front side, revealing its true color (blue) and ruining much of the "infinite ocean" effect. You can also see more mirroring in the glass. With a weaker main tank light (such as in some fresh water tanks) it might still work fine, though.
Otherwise if you like a cyan/greenish background box it's probably best to begin with a similar acrylic color. RGB LEDs can be used for fine-tuning, but they can't do miracles if the acrylic color is too mis-matched to begin with. Red LEDs are useless with a blue acrylic sheet, since the acrylic filters out red light anyway, so if you want to save money you might try dimmable blue LEDs only. White LEDs will appear like a combination of blue and green, since almost all the red is filtered out by the blue acrylic.
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Christian J
New member
I use acrylic sheets that are translucent/blurry to begin with, so no need for sanding at all.
When I tried drysanding transparent acrylic by hand (600 grit paper, I think) I got ugly corona effects from the scratches.
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Christian J
New member
You may get some mirror effect if the box light is too weak compared with the tank light hitting the back glass. (I attached a picture showing this a couple of posts ago, but it seems to have disappeared --can you only upload 5 files in total?)
Some things you can do to reduce mirroring:
* Shield the back glass from direct tank light, for example by using some kind of shading above the tank, or by moving the tank light more towards the front.
* Use a stronger box light source.
* Use a bright/reflective color on the box interior, especially the back and bottom. I don't think you need a blue-painted box background, try painting it white instead and let the acrylic sheet provide the blue color.
* Use an acrylic sheet color that lets through more light. I've seen blue acrylic sheets range from 4% to 12% light transmission (the figures likely depend a lot on the light color).
Some things you can do to reduce mirroring:
* Shield the back glass from direct tank light, for example by using some kind of shading above the tank, or by moving the tank light more towards the front.
* Use a stronger box light source.
* Use a bright/reflective color on the box interior, especially the back and bottom. I don't think you need a blue-painted box background, try painting it white instead and let the acrylic sheet provide the blue color.
* Use an acrylic sheet color that lets through more light. I've seen blue acrylic sheets range from 4% to 12% light transmission (the figures likely depend a lot on the light color).
syedjilani
Active member
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Christian J
New member
A while ago I tested an old 250 MH light resting directly on the tank rim, and that turned out much too bright for the background box to have any effect near the MH light cone. The tank is 18" high and 22" front to back. Maybe it's because I used a daylight color bulb (assuming these look brighter than bulbs with higher Kelvin ratings)?
karimwassef
Active member
That is gorgeous!
I'm thinking of using non-adhesive frosted film and spray painting it blue. This eliminates the need for the acrylic?
Then cardboard cutouts for coral, a dark blue poster board for backing and blue LEDs for backlighting.
Ideas? Feedback?
I'm thinking of using non-adhesive frosted film and spray painting it blue. This eliminates the need for the acrylic?
Then cardboard cutouts for coral, a dark blue poster board for backing and blue LEDs for backlighting.
Ideas? Feedback?
Christian J
New member
Which side would be painted? If the side towards the aquarium glass is white/unpainted it may not look so good, hard to say. Producing an even spray coating might be tricky also. But you could always give it a try.
A brighter background color reflects a little more light, not sure how import it is though. It also depends on how blurred (translucent) the film/acrylic is, if it's completely blurred you can even use a white or mirror background and it will not show through.
Christian J
New member
To elaborate: it may work if the blue light from the box is strong enough, but if not the film may look gray/white. This could happen especially in the corners, or where the aquarium light hits the aquarium's backside glass too strong.
karimwassef
Active member
Has anyone done this with LEDs? It looks good in the dark, but the tank lights are way too bright.
Christian J
New member
I use LEDs in the box for my tank project (about 14W of RGB LEDs in a 48 inch long box) but I haven't bought a tank fixture for it yet, so I don't know how well it will turn out together. Of course some LED brands are more efficient than others, so I could always try stronger ones if necessary. I could also replace the RGB LED with pure blue one for more output, since I don't use the red ones anyway.
What kind of tank fixture do you use? I'm not sure what's the best. An LED fixture with a narrow light beam may cause less light to hit the backside of the tank. OTOH, T5 tubes spread light over a larger area, compared with the more concentrated light cone of an LED (or MH?) fixture.
What kind of tank fixture do you use? I'm not sure what's the best. An LED fixture with a narrow light beam may cause less light to hit the backside of the tank. OTOH, T5 tubes spread light over a larger area, compared with the more concentrated light cone of an LED (or MH?) fixture.
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