View Full Version : Black Light

10-14-2014, 06:31 AM
Is there a setting to make a black light? Or is there a way to fake it in Lightwave?

10-14-2014, 07:24 AM
Black light??

Black color is lack of light, lack of photons at all visible wavelengths..

In old times people were using "negative light", negative value of intensity, to subtract light from some surface.
Not sure whether it will give you wanted effect.
(it has nothing to do with reality)

10-14-2014, 07:27 AM
yup, if looking for negative light than inversed intensity is what you are after.
If you;re looking for UV light than it's a completely different subject.

10-14-2014, 07:32 AM
give it a negative value, say -100 = absolute black, that simple

- - - Updated - - -

and if you add a colour to the light you will get its opposite

10-14-2014, 07:50 AM
Looks like Spotlight with -100% to -1000% Intensity and turn off shadows giving nice black cone.

10-14-2014, 08:49 AM
erikals did this not so long ago, might be useful (might not!).


10-14-2014, 11:15 AM
This kind of light?


10-14-2014, 03:11 PM
I'm pretty sure the op was looking for a UV light. In the states we sometimes call these "black lights". I'm sure swampy's on the right track.

10-14-2014, 08:58 PM
Agree with swampy and amurrell as to the OP's original intent. If so, then it's all about surfacing... saturated colors, luminousity maps matching the "painted" surfaces to make just those areas "glow," and a dark scene. Illuminate using an indigo colored light to tint all surfaces indigo (including anything white or neutral).

10-14-2014, 10:21 PM
Agree with swampy and amurrell as to the OP's original intent.

Yep. Those other guys need to get out more. :D

10-14-2014, 11:56 PM
FWIW, I've always called LW negative value lights "darklights".

(Not to be confused with "dedlights", which are viewpoint placeholders.)

10-15-2014, 03:19 PM
Yep. Those other guys need to get out more. :D

Not all of us grew up in the 70's

10-15-2014, 06:24 PM
I feel for those who missed it.

Then again, some of us never grew up. I feel for the ones who did.

10-15-2014, 08:14 PM
Not all of us grew up in the 70's

ROTFL. Yeahhhhh, that's true. :thumbsup:

10-18-2014, 09:37 AM
The reason I'm asking is because I thought I would get into the Halloween spirit and do a haunted house. Can we envelope the point light fast enough to do a strobe?

10-18-2014, 09:53 AM
I found a video that explained it by William Vaugn

10-18-2014, 10:37 AM
I found a video that explained it by William Vaugn
Which bit, the strobe or the UV?

To save you quite a bit of linking, look at this thread: just skip down to posts by the inimitable XSwampyX to find excellent examples of UV lighting via nodes in LW. http://forums.newtek.com/showthread.php?138201-quot-Magic-Lights-quot-useful-aka-quot-X-channel-Light-quot-nodal-applications-extended-spectrum/page1

10-18-2014, 03:02 PM
Now I saw a video on making a candle flicker. I thought that video plus adding speed would make a strobe but just tried it and couldn't get it to work

10-18-2014, 03:15 PM
Things to consider:

1) Envelope keyframes should be STEPPED.

2) Your strobe timing may run afoul of the frame rate. Weird things can happen with strobes: https://www.youtube.com/watch?v=RB0LYbKLrBw

10-23-2014, 09:03 PM
Since you can't keyframe anything alternating at a rate or frequency faster than the frame rate of the animation (eg. 80 flashes/sec in a 30 fps anim), the best you can do is turn the light on for 1 frame and off for the next and repeat the envelope. This would obviously give you a very noticeable/visible, 15 Hz flash rate. You could minimize the on/off distraction by not turning the light totally off, but setting it to 50% or something.

If you use fractional frames, then you'll get an undulating brightening and darkening of the staccato flickering... IOW, a temporal beat-pattern.

11-05-2014, 08:16 AM
I had to put this on the backburner for a while so now I'm beginning again. What I was wondering if I did a animation with the lights flashing and then do another without the lights and then combine them would I get a realistic strobe light in my animation?

11-12-2014, 03:06 PM
What would be the purpose in doing it that way?

The fastest strobe you can get is 15 fps (if anim is at 30 fps). So, just animate the light intensity on/100% for frame 0, off/0% for frame 1, set keys to stepped, set post behavior to repeat, and render.

11-12-2014, 08:22 PM
...and send some unsuspecting soul into a seizure. :)

11-13-2014, 06:10 AM
LOL... yep, you would want a fair amount of fill lighting or not reduce the strobe light to 0% in order to "smooth" out the flicker. Also, strobes and flashing anything tends to make .h264 compressors very unhappy... even worse when mixed with confetti.

11-13-2014, 06:25 AM
Back in the day, I used to try and run strobes at two or three times the BPM of the track for best effect. So for your average 140BPM Hard Trance track, I'd be running between about 4 and 7 flashes per second.

Still working on my multiple mirror ball effects... :D

11-24-2014, 02:45 AM
Ok, I missed something, how did the subject get onto strobe lighting, when it was about black lights? No where near the same thing.