Purple

[BenEdwards]

OK, so purple is blue and red, so logic dictates the transmission should be greater than a primary blue or red but it does not seem to be. Verry odd.

 

Basically ime looking for a rich purple and have a couple of 743s to light a person. The stage is around 8 meters wide. They are on a bar at the front of the stage.

 

Ben

[Albatross]

Really great purple Gels I've used are:

Lee 181 - Congo Blue ( It's purple !!!)

Lee 180 - Dark Lavender

 

Light through filters is always a reduction in transmission. Purple is always very dark, especially as it's at the high end of the visible spectrum.

 

Good luck !

[timsabre]

Congo blue is probably my favourite colour ever but it's only really usable in 1k par cans. Anything else and you hardly get any light out.

[adam2]

A roughly subjectively equal mixture of red and blue light produces magenta. If, as is likely, the red blue and blue filters also pass even a little green light then the mixture tends more towards pink.

 

Purple means slightly different things to different people, but is often a mixture of mainly blue and a little red. Alternatively some people regard purple as consisting only or primarily of light with a shorter wavelength than blue, in which case it should IMO be more correctly called violet.

 

Regardless of the exact wavelength or mixture of wavelengths desired, purple, violet, or deep blue are not easy colours to obtain by filtering an incandescent source. The output from an incandescent lamp inherently contains little blue or violet. Congo blue is indeed a possible choice as it passes blue, violet and just a little red. Unfortunately congo blue has a transmission of only about 1% and therefore requires an awful lot of watts to produce light of reasonable intensity.

 

Solutions include

 

Buy or hire some LED lanterns, deep blue or purple are impressive even from basic fixtures.

 

Buy or hire HID fixtures with daylight lamps and experiment with filters. As a very rough guide, 1KW of daylight HID with a deep blue filter is equivalent to 10KW of tungsten with the same filter.

 

Use plenty of high wattage lanterns, only viable if power supply and lantern stocks are sufficient.

 

 

 

 

 

[paulears]

I rather like mauve, as a purple but this perhaps isn't what you want. Trouble is beam spread. Are the 743s spotted narrow or wide? On narrow there may be enough, but saturated colours on wide is a glimmer.

[Ynot]

And of course even on a fresnel, spotting the beam down will focus a LOT of heat on the colour and give you a reduced life on the gel, even for high temp gels...

[kitlane]

Maybe the problem is that

. http://www.blue-room.org.uk/public/style_emoticons/default/wink.gif

[BenEdwards]

Thanks, I do have a load of LEDS, they are bright but cheap and don't seem to be able to get purple but now I know the mix will give it a go.

 

googled for HID stage lanterns and could not find any. Are they dimmable? A link two would be great.

 

Ben

[adam2]

HID lanterns similar to stage lighting lanterns do exist, but are relatively uncommon. No common type is dimmable hence the very limited use in theatre. Hid lanterns are primarily intended for retail display lighting and trendy lighting of office reception areas.

 

Despite the lack of dimming they are sometimes worth considering for theatre if a deep blue or violet is desired, especially if power is limited.

[Judge]

Ben, as stated a true righteous purple gel is 181 and this does indeed have the lowest transmission value of any gel in the book. A couple of 743s will be defeated by this. I would go a bit lighter and try 797 Deep Purple or 049 Medium Purple.

However they are more Magenta than Purple. And as interesting as that video is it is incorrect about magenta and purple being the same. Magenta is more pink, but.....

 

"Pink and magenta have the same hue. What distinction there is to be found between magenta and pink lies along other axes than that of hue. All pinks are magenta and all magentas are purple, and by extension, pink is a purple. However, it does not work the other direction: it does not mean that all purples are magenta nor that all magentas are pink, let alone that all purples are pink. "

 

So thats just about as clear as mud isnt it? What I find really interesting is the similarity between violet and purple - the RGB or CMY values of which are very close, and yet as stated, purple is not a spectral colour. In terms of wavelengths, violet is clearly at the short wavelength end, but purple consists of mixed wavelengths.

 

Here is a little page that talks a little more about how we interpret this phenomenon

 

https://jakubmarian....let-and-purple/

 

edit - I just discovered that Deep Purple, plus a few other faves were created by none other that Peter Barnes! Good work Pete.

 

http://www.leefilters.com/lighting/designer-list.html#peter-barnes

[alistermorton]

Regarding your LEDs, Ben, it's worth noting that ETC have two versions of some of their LED lanterns with different blue ranges. One of their (not cheap) lanterns struggles to get the really deep blues (and by implication purples) requiring the other version which is optimised for that part of the spectrum, so it may be that the cheaper LED fixtures will struggle to get a convincing very deep purple.

 

EDIT

 

L507 might be worth a look? Not as deeply bluey purple as congo, but still pretty purplish. Or L707 as mentioned above.

[timsabre]

Regarding your LEDs, Ben, it's worth noting that ETC have two versions of some of their LED lanterns with different blue ranges. One of their (not cheap) lanterns struggles to get the really deep blues (and by implication purples) requiring the other version which is optimised for that part of the spectrum, so it may be that the cheaper LED fixtures will struggle to get a convincing very deep purple.

 

This is very true, I have some chauvet tritour pars where the blue is quite greeny, and it is impossible to mix a decent purple with them.

[paulears]

Isn't it just that blue, red, green, cyan, magenta and yellow are hues that you learn easily? See magenta and say magenta. Magenta vs pink is just a litle extra. Purple is something more used in fabrics to describe a vague colour that people don't have a standard for. It never ever occured to me that Congo Blue was purple? I know the colour very well - but in a quiz would not have said purple.

 

This what I call purple - not sure what gel colour it would be?

[theatretechie]

I'm a big fan of Lee707 Ultimate Violet.

 

I stumbled across it in an unmarked folder when at RADA. Tried as an experiment and have used it on many designs since.

 

Its stunning on Dark/Olive skin tones, great for dance side booms.

[marktownend]

In response to the question in the OP's 1st sentence (and I know there are many others who could explain this better than me!), my understanding is that when you stick a gel in front of a traditional lamp it's subtractive colour mixing. This means that you start with 100% of the light output as it leaves the lamp, but by putting the gel in front you filter out parts of the colour spectrum and the transmission level is whatever is left over and whistles off out towards the stage. So as purple is effectively blue and red combined in whatever percentages happen to give your chosen colour then it's removing more of the light than either blue or red individually, meaning the transmission is lower.

 

With LEDs, it's additive mixing, so by adding some red to your blue to get your purple will give a brighter result than either red or blue.