Just to clarify

When I’m adjusting the highlights and shadows and all that with curves, and using the waveform display or parade, it’s essentially the same idea as this, right? 

The stuff he’s doing (1:20 mark)

Curves is the only thing I really use to make such adjustments...per the suggestion of Triem23. 

But he says “I’m going to go to primaries...” whatever that is. And there he manipulates controls that seem pretty easy and straight forward. We don’t have something like this? Curves is our best option? I understand that curves is pretty much the same no matter what you use. But there isn’t a layout like this in Hitfilm? 

I guess Lift, gain, gamma are essentially shadows, highlights, and mid tones. But for some reason when I hear “gamma” I think of something else. 



  • HitFilmer128619
    HitFilmer128619 Posts: 322
    edited May 2018

    And don’t get me wrong. Using curves isn’t that much of a pain. This just looks like less of a pain and a pretty smart concept. Easy to grasp and make simple, quick adjustments with the slide of a bar. 

    Especially when tweaking individual channels. 

  • Triem23
    Triem23 Posts: 20,069 Ambassador

    "Primaries" should be the same thing as "Color Correction Wheels."

    I always push Curves first cuz, once you learn those you'll realize a lot of the other tools are different interfaces for the same thing.

    I say Curves is the most important color tool, but Color Wheels are the second most important. 

  • Oh those were color wheels? 

    Whats up with the little slider things?  He just did a little zip zap poof. And it was done. No dragging points on lines or jacking around with color wheels. 

    And I thought the wheels were more useful for color GRADING. 

    I don’t even know where I am anymore...

  • Triem23
    Triem23 Posts: 20,069 Ambassador

    I didn't actually watch the video you linked (I'll do that at home on wi-fi), so I'll get back to you later, but I'm 90% certain you'll want Color Correction Wheels. 

    Remember any tools used in Color Correction can be used for Color Grading. Correction is just fixing "incorrect" color (too warm at noon, for example) and getting all the shots in a scene to have consistent color and tone. Color GRADING is the "cool look" stage. So the difference between the two terms is more about intent.

    While Hitfilm's effects list splits tools by Correction and Grading, "Correction" tools can be used for grading. But, the grading tools aren't good for correction. 

  • Triem23
    Triem23 Posts: 20,069 Ambassador

    Ok, after watching the video... And doing a little Google research because those controls weren't what I expected.

    First, let's discuss the term "primary/primaries." This is a one of those terms than can mean multiple things. Sometimes "primary" refers to a stage of the coloring process: primary color correction as the stage where you are matching footage so they all match. "Primary" can also refer to Color Wheels (In Vegas and Premiere, for several iterations Color Wheels were called "Primary Color Correction," while "Secondary Color Correction was a single wheel that operated on a color selected with an eyedropper/pipette tool).

    Now, Resolve started as specific color correction/grading software and didn't add NLE features till v12. With 11 versions as pure color correction it stands to reason Resolve has the easiest to use color tools. Arguably the most powerful, but I'll argue to mostly refute that.

    So, there's not much Resolve does Hitfilm can't, but in Hitfilm you may need to do more steps. 

    Those sliders shown at the bottom were new to me, but, after a minute I realized what they were. And they're 1) pretty basic 2) actually an alternate interface for the Color Wheels using sliders instead of dials. 

    Each control has four sliders. From left to right each slider is global (all channels), Red, Green, Blue. 

    Lift is a targeted adjustment of lower tones - the shadows. Gamma is a targeted adjustment of the mid tones. Gain is a targeted adjustment of highlights. Offset raises and lowers brightness across the entire range. Let me drop in a link to this article which goes into more detail and has some helpful graphs so you can visualize. Let me also note this article shows the normal color wheel interface.  https://www.provideocoalition.com/whats-in-a-name/

    Now, I've been saying Curves can duplicate many functions of other tools, and it turns out Curves can actually do Lift, Gamma, Gain and kind of do offset. 

    Let's pretend we have a curve and we've added three points from bottom left to top right One about 25% from bottom to top, one in the middle and one at 75%.

    Adjusting the 25% point up and down is lift - adjustment of shadows with the other two points pinning the mid and high values. 

    Adjusting the 50% point up and down is changing Gamma - mid tones. 

    Adjusting the 75% is the same as adjusting - you guessed it - gain... Highlights.

    Offset? Well, remove the three added points and move the bottom left corner up and that's almost raising Offset. Drop the top right point and that's almost like lowering Offset. In Hitfilm the Brightness slider in Brightness/Contrast is exactly the same as Offset. However since Offset is global Offset can clip. What I described with the Curve actually prevents clipping.

    Each of these controls in the video also had the individual RGB sliders. This can be replicated in Curves as you have individual curves for each channel. 

    So, what we have in the Resolve video is a special interface for faster adjustment compared to Curves. The trade off is Resolve defines the ranges for shadows, highlights and midtones, where using Curves and setting points you are controlling the value ranges. 

    In Hitfilm's Color Wheels the controls have a different layout than the sliders, but do basically the same things. The Shadow Wheel controls Lift. The wheel itself is a bit like pushing the individual RGB sliders around, except if you push to yellow on the wheel you get yellow. With RGB sliders to get Yellow you actually remove blue... The wheels are supposed to be intuitive since you see the color you are aiming for rather than having to remember how the color channels interact. The color wheels have a brightness slider for each wheel, which is the same as pushing the global fader on the sliders shown in Resolve.

    The Midtones wheel is the same as the Gamma adjustment, Highlights is Lift. 

    So, between Curves, those primary sliders in Resolve and the Color Wheels we have three interfaces that can all do the same thing. Ok, the Color Wheels have saturation sliders and saturation is something Curves can't actually adjust. 

    Side note: Color in video. Video is ADDITIVE color. We start with black and add light from the glowing phosphors/leds/lcds on the screen. Real life is SUBTRACTIVE. We start with a light source and objects absorb some colors and reflect others. 

    ADDITIVE color uses red, green and blue as primary colors (oh, look, a third meaning/use of primary - no wonder this is confusing). Adding red and green makes yellow. Adding red and blue is magenta. Adding green and blue is cyan. Adding all three is white. 

    Color can be mathematically modeled in several ways, and Hitfilm can use three of these models: RGB, HSL, and YUV. 

    The first model is RGB. This is adding linear values for each channel. For simplicity we'll use values of 0-100 (8-bit color is 0-255, 16 bit color is 0-65535, and internally color is usually computed as 0-1). 1-100 is easier to discuss cuz we can think of it as percentages.

    Reading left to right as RGB value of 0,0,0 is black. 100, 100, 100 is white. 100, 0, 100 is magenta (red plus blue).  100, 100, 0 is yellow (red plus green), etc. This is the base color model in most software because it represents direct control over the brightness of the RGB values the monitor is using. RGB is a good space for adjusting almost anything but Saturation. 

    Another model is HSL. This is "Hue, Saturation, Lightness" (Hitfilm has a Hue/Sat/Light effect). Again we'll use 0-100 values. 

    Hue is the "color." Pure Red is 0. Green is 33.33. Blue is 66.67. 100 almost brings us back to pure red, but has the smallest amount of blue. It's a color wheel! Saturation is "how colorful the color is." Saturation of 0 is always a pure gray, no matter the hue. Saturation of 100 is the most colorful of colors. Lighness is "how bright is this color?" Lighness of 0 is always pure black, no matter the Hue or Saturation. Lightness of 100 is a bright color. Lightness of 100 and Saturation of 0 is pure white, no matter the Hue. Lightness is sometimes referred to as Luminance,  Brightness or Value. HSL, HSB and HSV are all the same thing. Just different, confusing names. 

    HSL is designed to be intuitive, since instead of dealing with RGB values you're picking a color, saturation and brightness. Note, technically a "color" has defined Hue, Saturation and Lightness, but Hue isn't a commonly used term and I've found it easier to call Hue "the color" when explaining HSL. If we're being precise red is a hue. It's not a color until saturation and lightness are involved. To put it another way, red is a hue. Green is a hue. Dark, saturated green  is a color - "hunter green" . Light, desaturated red is a color - "pink."

    YUV (also called L.A.B or YCrCb) uses three color channels: Luminance (Black to White) Color Red (an axis moving between magenta and green) and Color Blue (an axis moving from blue to yellow). YUV is the color model analog video used for the signal (although the display was still RGB) There aren't too many effects in Hitfilm using this color space, but YOUR CAMERA DOES. When you're adjusting the White Balance of your t5 you're adjusting the blue/yellow axis. When adjusting the Tint on your t5 you're adjusting the magenta/green axis. Your television does this as well! Adjusting the Tint on a TV is adjusting magenta/green and adjusting Phase is blue/yellow. If you ever had a TV/VCR/DVD/Blu-Ray player with three video cables on the back that's what those were. One cable for luma, one for magenta/green, one for yellow/blue. 

    Remember RGB and HSL. Don't worry about YUV. No tools you're likely to use in Hitfilm Express work in YUV. 

    Ultimately any colors in an image are calculated as RGB, because that's what your monitor understands. HSL is an alternate interface sitting on top of the RGB. 

    So, the point of that digression into color theory? Curves are a very basic, "low level" adjustment of RGB values the bottom axis is the "input" value and the vertical axis is the "output" value. If I place a point at 25% and drag that halfway to the bottom what I've told the computer is "Take this 25 and make it 12." Then the computer draws the curve to smooth the surrounding values. 

    Levels Histogram (a Hitfilm effect) gives you three points, 0, 50 and 100. You adjust these three values and the computer smooths the transitions. If I drag the white point in Levels left about a quarter of the way, I'm telling the computer "change  75 (and higher) to 100.

    Gamma (this is a Hitfilm effect, but also applies to that gamma control in the Resolve video) is one point at 50. If I lower Gamma halfway I've told the computer" change 50 to 25," an, again, the computer smooths the rest of the values. 

    Color Wheels are an HSL interface. For sake of discussion let's pretend we have a single plane at 50% gray and we're adjusting the midtones color wheel. If we push it to yellow, you see the dot moving to yellow... That's the HSL interface. However, internally an RGB calculation is happening. It's really telling the computer "lower the blue values and boost red and green." this can be done in Curves, but it's more fiddly, since you're adjusting points on three individual channels. 

    I hope this isn't too much overload for one night. This is a complex topic and I have multiple books, hundreds of pages each, just talking color theory and modeling. 

    I do hope this illuminated why I've pushed you to start with Curves. It's a reasonably intuitive interface while giving a lot of direct control of the RGB values your monitor understands. Additionally, curves is doing everything Levels Histogram, Gamma, and Brightness/Contrast does as well as Exposure, Shadows/Midtones/Highlights or Color Balance and probably a couple of others.

    So, if you get comfortable with Curves and start to grasp the underlying numbers in RGB channels, you should be able to quickly learn all those other filters, because they're all specialized interfaces adjusting the same RGB values in the same way.

    Color Balance is a good example. You have a predefined range of shadows/mids/highlights. You'll have nice colors on the faders to help visualize, but pushing a shadows fader to blue is the exact same change as adding blue to the lower part of the curve while pulling down red and green. To restate an earlier point Color Balance is easier to use and more intuitive (the faders have color!), but you're adjusting the predefined value range by moving a predefined point. With Curves you have to manually set the points to define your ranges, but this means, ultimately,  Curves has more fine control.

    Shadows/Highlights is another example. Pushing the Highlight slider around quickly raises/lowers the value. Like Color Balance its using a preset value range and adjusting a preset point, and, again, Curves has more control.

    Stick with it and don't get discouraged. If you were taking college/university classes in this stuff you'd have,  literally, hours of lecture and discussion of what's been discussed in just this post. You're trying to absorb a lot of complex information at once. I've said it before, I'll say it now, and I'm sure I'll say it again: there's a lot to cover with color correction and I pushed you into starting with Curves because of its power and versatility. Now that you're starting to understand Curves, poke around in some of the other filters I've mentioned today and see if you can visualize  how adjusting their  controls is pushing around RGB values and how they relate back to curves. Just remember Color Wheels is HSL, so functions a little differently.

    Last note for tonight. Transparency/Alpha. This is just another color channel like red, green, blue. It can also be thought of from 0-100. 0 is transparent, 100 is opaque, anything in between is a degree of translucent. The numbers are adjusted mathematically just like the RGB channels. Ultimately a monitor doesn't understand alpha and, at some point, translucent  layers are combined into a final RGB value for display. 

  • You da man. Thanks.

    like I said, I just end up with questions when I watch tutorials using other software...the language and controls they use and all that. 

    I didn’t actually search the video but it was in my suggested videos so I took a look. I was totally tracking when he was taking about the different scopes and whatnot. And then he started making adjustments and I was like wait, how can I accomplish this in Hitfilm? Besides using the curves like I’ve been doing. I’m just now getting used to working with curves. And I like it. It just looked simpler when he did it. 

    Also, I always wondered what the Alpha channel was. I’ve tried messing with it in the past and it didn’t seem to do anything. Now I know why...I think. 

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