Actually, I'm trying to show that a magenta does exist.And that R + G = Y.
But a wide blue filter with low absorption could pass green light, but I would not call it a blue filter. As you noted above, we might agree on another color.
Well, one thing is clear. I am not disagreeing with you, you are disagreeing with me!
More than anyone else here perhaps, I know that films are sensitive to each wavelength of light according to their sensitivities.
However, you misstate my case. I say magenta exists and yellow exists. They are combinations of two spectral regions just as cyan is! You contend that magenta does not exist! So, you have misquoted me and you are missing the fact that subtractive systems consist of two portions of the additive system (in simple terms). Conversely, you may say that an additive system is one part of each two part subtractive system. Each refers to either density or absorption spectra.
And, you miss the point (or disagree with the fact) that a filter that makes an ortho film from a pan film, although possible, is not blue by the definition agreed to by anyone. It would be a composite of blue and green called cyan!
I applied the things I was taught in Ektacolor 37 paper, where we used a new green sensitizing dye and a new magenta imaging dye, in Kodacolor Gold 400 with a new green sensitizing dye, and in Ektaflex R and C which were built from the ground up with all new dyes. I might add that the green sensitizing dyes were a non-existant magenta in color.
Bob Hunt was our guru for color: http://www.sid.org/pressroom/040818.html and http://www.photomemorabilia.co.uk/Colour_Darkroom/Kodak_S1.html
You see, I learned this from the perspective of a subtractive system engineer for photo systems. IDK your background, but that is where I come from and how I explain things, using the texts that I mentioned earlier. I am truly sorry that we cannot meet somewhere in the middle, but as I see it, I can hand you a bottle of non-existent magenta dye. That is the bottom line!
Folks, just incase this is not clear, the ability for certain colors to get through fog better than others has zero to do with film's spectral sensitivity or how film works with filters.
What we have to get clear is that blue, cyan, yellow, red, green are all pure spectral colours You can assign a single wavelength to them, or a band of wavelengths you will want to call "blue" etc. But magenta is not.
Magenta does not exist except as a mix of blue and red.
A blue (!) filter will block red (and, as PE points out, every other colour too - Now that is a matter of blue or blueish.). So lacking the red component needed to create magenta, there really is no possibility on earth how the light coming through a blue filter will contain magenta.
We really have to stop thinking in terms of tri-colour!
It may be appropriate when discussing how CRTs and such produce colours, but it is completely out of place, wrong, here.
Yes. It is REALLY true.
You can split the entire EM radiation into a spectrum, and nowhere will you encounter magenta.
that's obviously not more accurate. There's nothing more accurate.
So do blue filters work to enhance fog or don't they? That's all I need to know.
Ray;
There are definitions of magenta. Magenta pigments and dyes exist! See my earlier posts.
PE
We really have to stop thinking in terms of tri-colour!
As I understand it,
Blue is most effecient at blocking Yellow, followed by Red... thus Magenta will be the last to go even though the filter may be quite bluish in appearence.
As far as blocking magenta, Green is the most suited,
as it can block all the components of magenta, while blue can only block half of them.
Any way, do you think that a typical filter that does block red and or blue... does so with 100% efficiency?
Even the good filters are not really perfect or IDEAL.
Can you explain how if we stop thinking in terms of tricolor, I will be able to create better photographs?
What ADVANTAGE is there to dropping this attachment to tricolor?
What happens to white light if you remove the green?
You wrote the following sentences:
1.
magenta is not part of the spectrum,
2.
magenta can only exist as a mix of spectral colours.
These 2 sentences are incongruent!
If magenta exists as a combination of two things which are present, the combination is by definition present!
You are simply saying what is clear... there is no particular wavelength that on it's own appears to us as "magenta".
(Magenta is in this sense is a synthetic color created in the brain.)
I take it you are referring to the philosophy of degrees of absolutes?
To paraphrase a line from the Big Bang Theory...
It is a little wrong to call a tomato a vegetable,
but it is very wrong to say it's a suspension bridge.
Ray;
There are definitions of magenta. Magenta pigments and dyes exist! See my earlier posts.
PE
So do blue filters work to enhance fog or don't they? That's all I need to know.
The B+W 470 is similar to the Wratten 44A.B+W Light Blue Filter 080
This filter renders blue tones lighter, but yellow, orange and especially red darker. “Aerial perspective” caused by haze and fog is increased, the sky will be rendered lighter. It is favored for tonal separation in object photography (darker reds, lighter blues), and also for the correction of excessively light gray values of orange and red colors under artificial illumination.
Its filter factor is approximately 1.5.
B+W Blue Filter 081
This filter produces the same results as the 080 Blue Filter, only more intensely. Therefore it has the same application. Its stronger effect makes it a mood-creating filter when photographing in fog or when aerial perspective is to be accentuated. Tonal separation in the photography of objects is also increased.
Its filter factor is approximately 2.
B+W Filter 470 (Blue-Green)
The correct filter for landscape photography, when haze will improve the mood of the photograph, but green should not be rendered darker.
How many nm is magenta then?
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