Light – it is an essential element for growing aquatic plants more beautifully. Various types of light including sunlight exist around us. Various forms of light exist in nature as well. The plants living in nature photosynthesize under the various forms of light. NA Lamp is for an aquatic plant aquarium that focuses on the way plants should be. This interview brings you the story behind the birth of NA Lamp.
Aqua Journal: What inspired you to develop NA Lamp?
Amano: It started out with something that I noticed in the sea at Sado Island.
Aqua Journal: What? You came up with the idea while you are diving in the sea?
Amano: Yup. While I was taking a picture. I had been wondering about lamps for some time. The grow lamps for aquatic plants existed for quite a while before that, but I thought “something is not right.”
Aqua Journal: What made you think that “something is not right”?
Amano: The conventional grow lamps for aquatic plants contained a lot of red light. It was based on the idea that the light in the red spectrum encourages the growth of aquatic plants. But it was merely the light intended for terrestrial plants.
Aqua Journal: Does that mean that light in the red spectrum boosts photosynthesis in aquatic plants?
Amano: Yes. In essence, such lamps were developed because one of the wavelengths used in photosynthesis was in the red range. However, it was still a land-based idea.
Aqua Journal: Is the condition of light different between land and under water?
Amano: Well, when you are on land, you feel like you are in the same level of brightness all the time during the day, don’t you? But it’s completely different under water.
Aqua Journal: So, what did you come up with in the ocean in Sado?
Amano: I was diving in the ocean to take an underwater picture that day. I was taking pictures of baby striped beakfish (Oplegnathus fasciatus) in a field of sea grass, Zostera marina, at a depth of about three meters. When I ran out of film, I happened to look at my arm. My red jacket looked black. What should have been red appeared black.
Aqua Journal: That sounds normal under water. What does it have to do with the light that aquatic plants need?
Amano: Yes, it’s normal. For example, some tropical fish have bright colors, but it’s hard to tell under the sea. Only when you bring the fish out of the water, you can see the bright colors. This is because red light does not reach under the sea and you are surrounded by a lot of blue light.
This red organism was seen at the depth of 30 m near the ocean floor at Sado Island. Although it appears dark to naked eyes, it appears brilliant “red” on film after it was captured by a camera with a strobe light.
Aqua Journal: Ah, that’s why your red jacket looked black.
Amano: Yes. But what amazed me was that Zostera marina was photosynthesizing with a lot of bubbles on them. Seeing that with my own eyes made me suspect that Zostera marina may be conducting photosynthesis using the blue light. They might have adapted under the condition.
Aqua Journal: So that became the trigger for the birth of NA Lamp and the drive for its development.
Amano: That’s right. Later on, Matsushita Electric Industrial Co. launched their indoor lamps called “Palook.” I tried it and found that it was better than the grow lamp for aquatic plants that I was using before. A “Palook” lamp is a daylight lamp and colors appear more natural under it. As a matter of fact, it had a lot more blue spectrum than the reddish grow lamp for aquatic plants. Since a lamp has a certain color proportion, if red increases, blue decreases and if blue increases, red decreases.
Aqua Journal: So the indoor lamp was better for aquatic plants?
Amano: Well, no, it had more to be desired. After all, I was thinking about developing a better lamp intended for aquatic plants. So then I proposed directly to Matsushita Electric Industrial Co. to jointly develop the lamps for aquatic plants. I said to them, “How about a lamp that contains blue light like this.” But they told me that couldn’t be right since they already had a plant grow light with red spectrum in their products.
Aqua Journal: Ah, but the light for “plants” turned out to be the light for “terrestrial plants?”
Amano: That’s right. We had a lot of difficulty initially. A lot. Partly because they already had a product. But I explained at great length that in the case of aquatic plants, a light with blue spectrum is better so that aquatic plants can utilize the light under water. Then they got interested.
Aqua Journal: The new lamp development must have started from then on.
Amano: Yes. After that, I visited Sado many times and collected a variety of information. For example, the period you feel bright is very short from 11:00 AM until 2:00 PM. Between 11:00 to 14:00 the sunlight comes relatively straight into water. In the period before or after that, the entry angle of the sunlight is small, and the light reflects off the surface and does not come into water. It’s still bright above, but it is already getting dark below. I also studied about color temperatures of light in detail.
Aqua Journal: Um, is a color temperature something that can be measured?
Amano: Yes, you can measure it. When I take a picture indoors like in a studio, I use a strobe or halogen lamp. In such a case, it is necessary to find the color balance of an artificial light source using a device called a color temperature meter. The color temperature is expressed in a unit called Kelvin (K). When I was taking underwater photographs in Sado, I measured the color temperatures of light in the water during the period that the light came into the water. It was around 8000 K. While I was trying lamps with various color temperatures after that, I came to the conclusion that the optimum color temperature for aquatic plants was 8000 K.
Aqua Journal: Ah, that must be the reason why the color temperature of NA Lamp is 8000 K..
Amano: Right. The 7,800 to 8000 K color temperature range seems to be the most suitable for aquatic plants not only for the growth of aquatic plants but also for color rendering as well.
Aqua Journal: So the color temperatures and the blue light were the key elements for the development of the NA Lamp?.
Amano: Yes. This does not mean that red light is not necessary. Don’t take this wrong. It’s not difficult to change the color temperature of a lamp.
For example raising the color temperature to 9,000 K or 10,000 K is simple. However, the light becomes bluish as the color temperature increases, and it starts to deviate from the original natural color. What matters is the color balance. It’s best that colors appear natural, isn’t it? When you look at nature, like in a river, the light is even more limited. For example, light reaches below the surface for only one hour in a day. Aquatic plants photosynthesize as if they were eagerly waiting for the time.
Aqua Journal: I suppose that you cannot tell the condition of light in the natural habitat until you actually go to the place..
Amano: That’s right. In a jungle especially, all around you is green. The sunlight goes into a river after getting diffused by various trees and plants.
Aqua Journal: What does diffusing mean?.
Amano: It means that light scatters. The light in a jungle reflects off the green and breaks up into blue and green light and then they penetrate the water.
Aqua Journal: So, it means that the light with more green and blue spectra can penetrate the water in primeval forests and jungles, isn’t it? New green lamps were added recently to the NA Lamp product line. Don’t they have different color components from the conventional ones?.
Amano: They have a little more green than the existing ones. To put it simply, the colors of aquatic plants in water appear more natural. Green and red colors appear true and more beautiful. The lamp that allows aquatic plants to appear natural seems to be good for them after all. The light that makes aquatic plants appear extremely blue or red is not very good.
Aqua Journal: I have not given much thought to natural light before. I see that NA Lamps were born from the curiosity of light from various angles and sharp observation of nature..