And even if there were a control to adjust the saturation
There is, it is the "color" control, which really is designed to adjust a composite Y/C signal (i.e. the kind carried by the yellow video cable in a red/white/yellow RCA cable combo) rather than individually adjust each primary. Using it desaturates each primary equally, and also decreases their lightness (Y) equally, but as you can see from the RS1 gamut chart each primary is oversaturated by a different amount. Fixing the saturation of one color using the "color" control results in the others being off, and the lightness of all three primaries being too low.
macgyver655 wrote:
it still would not correct the primaries or the shades in between.
Not quite - the color control can change the primaries (digitally), it just changes them all simultaneously so it's essentially useless for fixing this problem.
Ok, back to "some" confusion. What if the RS1 did have an individual color control for each RGB? Would that fix everything or only something? _________________ macgyver566@gmail.com
Joined: 12 Jan 2007 Posts: 12856 Location: West Seneca NY
TV/Projector: Marquee 8000, 8500 And a 9500LC RetroIV , 2 Longbow 8500 Ultras(2004!!)Hd145's , Ampro 3600, a G90!!
Link Posted: Mon Nov 28, 2011 8:17 pm Post subject:
"What if the RS1 did have an individual color control for each RGB? Would that fix everything or only something?"
Yes and no.To really get every aspect of color calibration you need controls also for the secondaries. And for each control only adjusting the amount of RGB will only change those amounts in every greyscale point and not change the color itself. To do that you need to be able to adjust each attribute of the colors, Hue, saturation and lightness for both primary and secondaries. So this goes back to your question it depends on what controls for each RGB you have.
Not sure what the RS1 has.
Ok is that close kal?
Athanasios _________________ Don't blame your underwear for your crooked ass~ unknown Greek philosopher
"The government can't control the economy without controlling the people" RR
One Smart Dog!!! Tom Bauerle to Andre Cuomo" Elliot Spitzer Screwed some Prostitutes, you screwed the Constitution" On his call to Cuomo to Resign!!!
Joined: 06 Mar 2006 Posts: 12344 Location: Ottawa, Canada
TV/Projector: JVC DLA-RS56
Link Posted: Mon Nov 28, 2011 8:39 pm Post subject:
I think the problem is that I'm not sure what is meant by "individual color control for each RGB". What exactly is being adjusted?
One control per colour isn't enough, that's for sure.
A primary point is just that: A point. You can't adjust a point to anywhere in space with only one control (you can only adjust along a line). While something like an RS1 has oversaturated primaries, they also lean towards other colours. If you only had one control and that control was only meant to affect the saturation of the colour, then the colour would desaturate in a straight line towards the D65 point if everything else was perfect (which it usually isn't).
That works if the tint of the colour is perfect but just oversaturated:
But not when it leans towards other colours:
In relation to the 'perfect line' on the RS1 the green primary is shifted the left, and the red and below are below.
If you were to use a control that adjusted just the intensity of these 3 colours the dots would move towards the center of the triangle in a straight line but miss the correct points at the tips of the triangle.
So you may get close, but not perfect.
Which is why a properly implemented CMS has more than just 1 adjustment per colour. It has ways to adjust the primaries and secondaries separately.
Link Posted: Mon Nov 28, 2011 8:52 pm Post subject:
kal wrote:
You can't adjust a point to anywhere in space with only one control (you can only adjust along a line). While something like an RS1 has oversaturated primaries, they also lean towards other colours. If you only had one control then the colour would desaturate in a straight line towards the D65 point if everything else was perfect (which it usually isn't).
This is it. This is what I was thinking when "I got it"
I just got slightly confused with hogs post and just wanted to clarify.
Now my next question. Why would none of the adjustments that I posted in the post I deleted (if you remember them) not be considered possibly a hue and/or saturation adjustment? _________________ macgyver566@gmail.com
Joined: 06 Mar 2006 Posts: 12344 Location: Ottawa, Canada
TV/Projector: JVC DLA-RS56
Link Posted: Mon Nov 28, 2011 9:04 pm Post subject:
I forgot to mention: Usually when there's only one control per colour, it changes only the light output, not the saturation. Changing the light output (Y value) is not what we want to do at all.
macgyver655 wrote:
Now my next question. Why would none of the adjustments that I posted in the post I deleted (if you remember them) not be considered possibly a hue and/or saturation adjustment?
I remember quickly looking at what you posted and thinking "I have no idea what any of this stuff means". It was (to me) pretty useless without some explanation of what the controls are. None of the terms seemed to be related to adjusting primaries or secondaries for the 6 colours we care about: R G B Y C M.
If it would have been a CMS, it would have likely had at least 2 controls for each of these 6 colours. That much would have been obvious.
To really grasp this you need to understand how the CIE diagram works in terms of displaying a greyscale on it and the 6 points and how they interact. Once you grasp how the giant triangle works (it's actually 3D), you're golden.
Link Posted: Mon Nov 28, 2011 10:34 pm Post subject:
Sorry for the confusion - kal seems to have a handle on things here so I'll spectate for a bit _________________ There are 10 types of people in the world, those who understand binary and those who don't.
Link Posted: Tue Nov 29, 2011 12:11 pm Post subject:
Okay then! Mac, please ignore what I'm about to post as it will most likely confuse you further. It's more nitpicky than anything else.
kal wrote:
I forgot to mention: Usually when there's only one control per colour, it changes only the light output, not the saturation. Changing the light output (Y value) is not what we want to do at all.
kal, I thought your entire CMS explanation was excellent. Regarding the underlined comment above, I do want to point out that a good/complete CMS will have controls that allow you to change the lightness (Y) of a primary or secondary in addition to changing the x and y coordinates. Using green on the RS1 as an example, on a physical level (regardless of whether you're using an HSL or an RGB CMS) you're actually mixing blue and red in with green to create a new, less saturated green primary. When you do this, the lightness (Y) of the new green primary will increase since you're adding light. As it states in your guide, since the Y of a primary (or a secondary) is based upon the Y value of 100% white, the Y of green will have to be re-adjusted (decreased) to meet the proper % value of Y for white. If your CMS has no lightness controls, then you could be left with some rather large dE's for your primaries and secondaries - especially in the case of something like the RS1 that has significantly oversaturated primaries that requires a lot of mixing to be desaturated. So technically speaking, you do want to adjust Y, but only after you adjust x and y.
What's funny about me discussing this with you is that it was your guide that broke the code for me on how to completely calibrate a projector - before that it was all Greek to me I remember sitting in my buddy's basement switching back and forth between HFCR and your guide (which I had downloaded to my laptop) and going step by step to calibrate his Optoma HD7100, which had a CMS in the service menu. What an illuminating experience...after that things started to actually make sense! Of course when I sat down with my Radiance's CMS for the first time to calibrate my 2nd RS1, that really threw me for a loop because I'd never used an RGB CMS before, only an HSL one, and to the amateur HSL makes much more sense. However after figuring out the Radiance CMS, I have to say that RGB CMS's give you a much better understanding of what you're actually doing when you digitally adjust a primary (in terms of mixing colors), so ultimately I prefer that method. Maybe you could update your guide to include a section on using an RGB CMS since the Radiance is a relatively popular VP? I'd be glad to offer some help if you didn't want to do the grunt work yourself
Anyways, I know the intent of what you were trying to communicate to mac about the lightness thing, but I figured I'd throw it out there for discussion's sake. I thought your explanation to mac regarding his most recent (deleted) post was excellent. Hopefully your guide sheds some light on the subject for him as it did with me! _________________ There are 10 types of people in the world, those who understand binary and those who don't.
Joined: 06 Mar 2006 Posts: 12344 Location: Ottawa, Canada
TV/Projector: JVC DLA-RS56
Link Posted: Tue Nov 29, 2011 1:19 pm Post subject:
HogPilot wrote:
... a good/complete CMS will have controls that allow you to change the lightness (Y) of a primary or secondary in addition to changing the x and y coordinates.
Good point! I probably should have written "Changing only the light output (Y value) is not what we want to do at all." instead. (That would have been more in line with what I was thinking). I didn't get that across right.
HogPilot wrote:
Maybe you could update your guide to include a section on using an RGB CMS since the Radiance is a relatively popular VP? I'd be glad to offer some help if you didn't want to do the grunt work yourself
I'll probably be re-vamping it bit if/when I get a new projector. That'll let me play around a bit with a recent CMS to get my bearings again as it's been a while since I've been in the guide in detail. I wrote it when I was doing a complete greyscale calibration on my CRT projector for the first time and had never actually used a CMS at all (since CRT projector's don't have one, nor did I need to use an external processor on mine).
Link Posted: Tue Nov 29, 2011 11:02 pm Post subject:
Once more, mac I'll caution you to not read what I've written here as it will most likely further serve to confuse you until you have a solid grasp on the gamut portion of kal's calibration guide
kal wrote:
HogPilot wrote:
Maybe you could update your guide to include a section on using an RGB CMS since the Radiance is a relatively popular VP? I'd be glad to offer some help if you didn't want to do the grunt work yourself
I'll probably be re-vamping it bit if/when I get a new projector. That'll let me play around a bit with a recent CMS to get my bearings again as it's been a while since I've been in the guide in detail. I wrote it when I was doing a complete greyscale calibration on my CRT projector for the first time and had never actually used a CMS at all (since CRT projector's don't have one, nor did I need to use an external processor on mine).
Kal
That would be awesome! When I did my first calibration with a CMS (on the aforementioned Optoma HD7100 that belonged to my buddy), there were controls for each primary and secondary labled hue, saturation, and lightness, which made sense to a layperson with a basic understanding of the CIE chart and basic color terminology.
However when I switched to the Radiance, I found that the RGB CMS they use works quite differently! For each primary or secondary you get controls labeled red, green, and blue (I believe the CMS on Samsung's displays works the same way). Although the process of using these controls is a little more tricky and less intuitive, it more accurately reflects the underlying mechanics of what's happening inside the light engine so I actually prefer it to the HSL method. Using the red primary as an example, you'd get three controls with the following default values: red 1024, green 0, blue 0. Increasing the value of green or blue moves red across the CIE chart towards that respective primary, allowing you to adjust red's x and y coordinates; decreasing the value of red decreases the lightness of red, which is the 3rd (usually unseen) axis of the CIE chart. The secondaries have the same red, green, and blue controls (starting with a value of 512 for each control), but adjusting them is more tricky because one control can potentially move a secondary in all 3 axes. As before, adding a primary to a secondary moves the secondary towards the primary on the CIE chart and also increases its lightness.
Anyways, I figured that including a discussion and directions for this type of CMS in your guide might be beneficial as it operates quite differently (and less intuitively) than an HSL CMS.
If adding pictures to this would make it much easier for newbies to understand, I could probably do that as well. _________________ There are 10 types of people in the world, those who understand binary and those who don't.
Link Posted: Tue Nov 29, 2011 11:25 pm Post subject:
HogPilot wrote:
Once more, mac I'll caution you to not read what I've written here as it will most likely further serve to confuse you until you have a solid grasp on the gamut portion of kal's calibration guide
Actually quite the contrary. Alot of this discussion only further supports my dislike of digital technology and gives me further ammunition to bash it at every chance I get........... _________________ macgyver566@gmail.com
Link Posted: Tue Nov 29, 2011 11:28 pm Post subject:
macgyver655 wrote:
HogPilot wrote:
Once more, mac I'll caution you to not read what I've written here as it will most likely further serve to confuse you until you have a solid grasp on the gamut portion of kal's calibration guide
Actually quite the contrary. Alot of this discussion only further supports my dislike of digital technology and gives me further ammunition to bash it at every chance I get...........
Don't worry, it's natural to dislike/bash things that you don't understand
Just kidding! Kind of... _________________ There are 10 types of people in the world, those who understand binary and those who don't.
Link Posted: Tue Nov 29, 2011 11:38 pm Post subject:
macgyver655 wrote:
HogPilot wrote:
Don't worry, it's natural to like/praise things that you don't understand
Just kidding! Kind of...
Right back at ya.....
I'm not liking/praising anything here, just explaining how it works _________________ There are 10 types of people in the world, those who understand binary and those who don't.
Joined: 12 Jun 2007 Posts: 1070 Location: Charlotte, NC
Link Posted: Fri Dec 02, 2011 2:12 pm Post subject:
Oh, I didn't know we had a whole thread for this now. Thanks Kal! Anyway, you all know I have an old RS1 now with these nasty primaries and I'm on the hunt for an affordable CMS or processor, whatever. Would a Lumagen HDQ do the job? I assume the DVI ports can adapt to HDMI? _________________ "Coffee is for Closers."
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