Using gels to change light spectrum

Firstly. I am a newbie.

Proven by my antics last night when i had my 600w hps too close to my 1mnth plants, thinking that heat was the only reason not to have it too close.

My light is in the blue spectrum. I studied and work in film&tv.

The question

Why can't i change the spectrum for grow with CTO gels?

The same gels that we use in the industry that when measured and seen, is the same as it would be in the evening or as tungsten. I've heard reasons like it blocks out too much. Just hoping someone could explain it properly.

what? hps...blue spectrum? I think its more red.

what spectrum are you trying to achieve?

what are CTO gels?

like a film/screen that goes over a light /lens / camera / flash ...supposedly changes light spectrum?

sorry. MH bulb. Gel to pull it toward orange. CTO = color temp orange. The question really is what valuable spectrum do gels block?

A gel works by removing certain colors. It's a common misconception that gels add color to the light. Gels can't add color. If the desired frequency isn't present in the light in the first place, or is present in low amplitude, a gel won't add more of the color. The sodium vapor lights used in parking lots, for example, emit only a narrow frequency of orangish light. Placing a CTB gel over one of these will not produce blue light; it will absorb the orange and pass almost no light.

So, in theory, if you used a bulb that put out maximum or high frequency ranges all across the spectrum you could use gels to 'fine tune' the light plants would receive from one bulb by blocking/absorbing unwanted light frequencies according to what spectrum the plants would need during each different stage of growth. But you could not just use a metal halide or a high pressure sodium bulb and with the use of gels provide plants with all they would need when it comes to light spectrum.

But after reading some on the subject it appears that such gels do not work the same with grow lights as with stage lights or lights used by photographers.

It would be best to stick with what has long been proven to work. Metal Halide for the vegetative stage of growth, High Pressure Sodium for the flowering stage of growth, or a combination of each for either or both stages of growth.

If someone uses a 600-watt or 1000-watt light they can use a dual filament bulb that puts out both MH and HPS light spectrums. The 600-watt would put out 300-watts of both MH and HPS and the 1000-watt would put out 400-watts of MH and 600-watts of HPS.