Why the LUT Strength Limitation?

Red Prince wrote on 7/28/2018, 7:09 PM

Why, oh why, does the Vegas LUT plugin not allow us to enter a negative strength or a strength greater than one? Does Magix not know that some of the best effects are produced by a negative strength (s<0), and some by an exaggerated strength(s>1)?

It is fine that the slider is limited to the 0-1 extent, but it should allow us to type in values outside that range. Alas, as it is, if you type any value < 0, Vegas will immediately change it to 0.000, and if you type anything > 1, Vegas will force it into 1.000. Argh! Gah! 😠 😒 🆘

Yes, I know that many LUTs would look weird outside of 0-1 interval, but so what? We are not stupid, we can see when going outside of the interval does not work. But there are LUTs where it makes perfect sense to go < 0 or > 1, so why is Vegas deliberately curbing our creativity by being rigid?

Please, fix it!

Comments

Musicvid wrote on 7/28/2018, 9:13 PM

But there are LUTs where it makes perfect sense to go < 0 or > 1

Can you show us some evidence and examples of that, and how it looks clipped back to REC 2020? I mean, even a billion colors in 10 bit still isn't infinite, is it?

It all sounds kind of hyperspace to me....

Red Prince wrote on 7/28/2018, 10:55 PM

Hyperspace, eh?

Here is my (as in I made it from scratch) LUT to convert an image to grayscale using Rec 2020:

TITLE "Rec 2020"
DOMAIN_MIN 0 0 0
DOMAIN_MAX 1 1 1
LUT_3D_SIZE 2
0 0 0
0.2627 0.2627 0.2627
0.678 0.678 0.678
0.9407 0.9407 0.9407
0.0593 0.0593 0.0593
0.322 0.322 0.322
0.7373 0.7373 0.7373
1 1 1

And here is a version that keeps the primary colors unchanged, while applying the Rec 2020 grayscale transform to the secondary colors:

TITLE "Rec 2020 for Secondary Colors"
DOMAIN_MIN 0 0 0
DOMAIN_MAX 1 1 1
LUT_3D_SIZE 2
0 0 0
1 0 0
0 1 0
0.9407 0.9407 0.9407
0 0 1
0.322 0.322 0.322
0.7373 0.7373 0.7373
1 1 1

If you could apply the strength of -1, you would be doubling the saturation of the secondary colors, producing a very interesting effect.

Since I know how to manipulate LUTs mathematically, I can easily make another LUT which acts as if the above-mentioned secondary LUT was used with the -1 strength:

TITLE "Rec 2020 Boost Secondary Farba"
DOMAIN_MIN 0 0 0
DOMAIN_MAX 1 1 1
LUT_3D_SIZE 2
0 0 0
1 0 0
0 1 0
1.0593 1.0593 -0.9407
0 0 1
1.678 -0.322 1.678
-0.7373 1.2627 1.2627
1 1 1

But not everyone can do that, and even for me it would be easier to use one LUT instead of two to experiement with the proper adjustment. Here is another creation of mine, doing the opposite, i.e., turning the primary colors into gray, while leaving the secondaries untouched:

TITLE "Rec 2020 for Primary Colors"
DOMAIN_MIN 0 0 0
DOMAIN_MAX 1 1 1
LUT_3D_SIZE 2
0 0 0
0.2627 0.2627 0.2627
0.678 0.678 0.678
1 1 0
0.0593 0.0593 0.0593
1 0 1
0 1 1
1 1 1

Again, setting the strength to -1 would double saturation of primary colors, while keeping the secondary colors untouched, just as the following does with the strength of 1:

TITLE "Rec 2020 Boost Primary Farba"
DOMAIN_MIN 0 0 0
DOMAIN_MAX 1 1 1
LUT_3D_SIZE 2
0 0 0
1.7373 -0.2627 -0.2627
-0.678 1.322 -0.678
1 1 0
-0.0593 -0.0593 1.9407
1 0 1
0 1 1
1 1 1

Among others this would be one of the LUTs useful in restoring old colored Czech movies from the 1950s and 1960s to their original beauty from their faded status. No hyperspace there.

I used this method in a set of Photoshop plug-ins I wrote back in the 20th Century (they are old, and no longer supported, so please do not try to pay for the registration that page still says to do). So I do know what I’m talking about.

Nor is it my original idea. I learned about it from others. For example, you can increase the contrast of an image by using negative strength on a decrease-contrast LUT. This is a well-known to authors of video effects. Otherwise I wouldn’t have said, “Does Magix not know that some of the best effects are produced by a negative strength (s<0), and some by an exaggerated strength(s>1)?” Because I am genuinely puzzled why they do not allow us to do it.

Red Prince wrote on 7/31/2018, 1:38 PM

I was really hoping someone official from Magix would have something to say here..............

Red Prince wrote on 8/6/2018, 6:45 PM

Well, I guess people want me to show you how it works without the strength limitation.

So, here is some random picture of some kid posted by someone somewhere on the Internet (really, I have no idea where it came from):

Here is the same picture processed by the 100% strength of a Bleach-Bypass-type LUT of my own making:

And finally, here is the same picture using the same LUT but these time shown with the -100% (yes, negative 100%, a.k.a, -1.0) strength:

Now, that may not be something one might want to do all the time, but when you need it, you need it. So, it would be nice if Vegas Pro let us do it.

P.S. I have edited this message because I accidentally hit the save button before uploading the third picture.