In this final part we’ll look at how Adobe Premiere handles full swing, and we’ll try to assess how we should go about each of the nine combinations we looked at in Part Two.
What color space does Adobe Premiere Pro use internally?
Adobe Premiere Pro works in the sRGB color space internally. Most people edit on normal computers, with normal displays, with normal graphics cards. Therefore, it is important to conform to sRGB so WYSIWYG.
How can we confirm this? Adobe tells us, but the simplest test is to create an 18% grey (I’m not calling it middle grey) Color Matte using the hex values #777777. When you do this, this is what you see in the YC waveform:
The first one shows the 25 fps waveform, which lists the IRE range in voltages. This corresponds to 0.65 V. The second shows the 24/30 fps waveform, which lists the IRE range as IRE. This corresponds to 46.6 IRE (%).
Guess what? This is what 18% middle grey is for the sRGB color space.
Let’s see how full swing images are handled.
How are full swing images handled in Adobe Premiere Pro?
No matter what the input color space, everything is mapped to sRGB. This happens internally and automatically, and there’s nothing you can do about it.
Remember, your footage does not change, only the timeline. All effects and filters are calculated based on the sRGB space. The math and the viewing spaces stay constant, and everything is brought down to the sRGB ‘level’.
Now, let’s tie this knowledge to the final part of the puzzle, the YC waveform. This is where things get murky. Clench it.
How is the YC waveform displayed for full swing images?
First, the answer:
- If you open a new sequence (Right click on media and select New Sequence from Clip) using a Rec. 709 video file, the YC Waveform will always be within 0-100 IRE.
- If you open a new sequence using a full swing file (CinemaDNG, Arriraw, Redcode, etc.), the YC Waveform will be stretched to -0.6 to 109 IRE.
Let me explain how the -0.6 and 109 comes about. An sRGB image displays white at 255 and black at 0. If you open a new sequence using a full swing file, Adobe Premiere Pro assumes correctly that it does not correspond to 16-235 (Rec. 709), and that there might be data in the shadows and highlights worth preserving. If Premiere Pro didn’t do this, and it tried to clamp down the file, you would see clipped highlights and crushed blacks by default. Because of this, if you open a RAW file in Premiere Pro, it looks perfectly okay!
Now, Premiere Pro cannot change the YC waveform methodology or the Rec. 709 standard, and it must include the additional data in the waveform if you want to know it’s there. In fact, if Premiere Pro didn’t do this, you’d think something was wrong, and that Premiere Pro is eating some of your bits.
Since 0 IRE corresponds to 16 and 100 IRE corresponds to 235, then 0 bits should correspond to -0.6 IRE and 255 bits should correspond to 109 IRE. That’s what we see:
The above image shows the RGB Curves effect allowing the image to go beyond studio swing to finally clip at -0.6 IRE and 109 IRE.
Now here’s where things get murky. When you open an image for the first time, do you always see the YC waveform in full swing? No. I don’t think this is a bug in Adobe Premiere Pro, but a design flaw. It always shows you the full swing range, but since most RAW cameras shoot in a flat gamma, the waveforms stay within 0-100 IRE; and we assume the extra space isn’t there. It only rears its head when you grade the image.
So what’s the design flaw? Premiere Pro shows you that your stuff is there, which is good, but it also allows you to grade outside the studio swing range which is not so good if that’s what you’re delivering to. There should be a clear mention of this which there isn’t.
Anyway, just to put this thing to rest, whenever you open a full swing sequence, the waveform will encompass the entire region of -0.6 IRE to 109 IRE. However, here’s the frustrating part. Just because you have all this extra room to play with doesn’t mean Adobe Premiere Pro will let you! Depending on the effect you use, your mileage may vary!!
Here are some of the effects I tested in full swing mode (please try to control your anger):
- Luma Curves: -0.6 to 109 IRE
- Luma Corrector: -0.6 to 109 IRE
- RGB Curves (one of the most used effects): -0.6 to 109 IRE
- Levels: 0 to 100 IRE (Even in full swing mode!)
- Three-way Color Corrector (of the most used effects): 0 to 109 IRE (How strange!)
- RGB color Corrector: -0.6 to 109 IRE
This ‘bug’ was supposed to be fixed, but as of version v7.2.1 it has not been fixed. So, here’s where things stand:
- If you start a studio swing sequence, Adobe Premiere Pro will not allow you to go beyond 0-100 IRE, no matter what effect you’re using (including the ‘rogues’ listed above). Phew.
- If you start a full swing sequence, Adobe Premiere Pro will allow you to go beyond 0-100 IRE, but it depends on which effects you’re using.
The key word is ‘allow’. It is a relief to know that you can open a Rec. 709 or studio swing sequence and not worry about a thing. If you open a full swing sequence, then you should be way more careful.
Just as an aside, what if you wanted to start a new sequence without referencing a clip? From scratch, follow these steps:
- File > New > Sequence… or Right click > New Item > Sequence…
- Go to the Settings tab
- Under Editing Mode, choose ‘Custom’
- Choose your project resolution, etc.
- For studio swing, uncheck ‘Maximum Bit Depth’. For full swing, check ‘Maximum Bit Depth’:
- If you inherit a timeline from somebody you can quickly check the Sequence settings to know whether the timeline is full swing or studio swing.
- Can you change it by checking or unchecking the box? No. You have to start from scratch, and then copy-paste your timeline. This works.
Oh, the stuff they don’t teach you…
How Adobe Premiere Pro handles the nine circles of hell
Let’s make it a chart, for easy reference:
|Combinations||Input||Output||What to do?|
|2||Full||Studio||Study the YC waveform and ensure levels stay within 0-100 IRE.|
|3||Full||Both||You’ll have to export twice, as per combinations 1 and 2.|
|7||Both||Full||Start sequence in full swing.|
|8||Both||Studio||Start sequence in studio swing.|
|9||Both||Both||Start sequence in full swing. You’ll have to export twice, as per combinations 1 and 2. Study the YC waveform and ensure levels stay within 0-100 IRE.|
All said and done, most of the time, you don’t have to do anything; just ensure your YC waveform stays within 0-100 IRE. In fact, if you know you’re delivering for broadcast and that’s your main priority, then why not start with studio swing? It’s as simple as it gets.
I hope this detailed look at full swing and studio swing within Adobe Premiere Pro has made your life easier. Give me a hug.