Revised colors for Celestia v1.5.0pre4

[dirkpitt]

I think the real problem is, none of the current versions of Celestia have adjustable gamma/color matching. One solution might be to add a gamma slider, but I'm not sure how simple that'd be for Windows and Linux.

However the fact remains it doesn't really solve the general issue of lack of color matching support in Celestia. As an interim measure, I'd recommend using any of the widely available free monitor gamma adjustment utilities.

[LordFerret]

Aside from the gamma problem, I don't suppose a solution would be to define a Celestia palette based on a digital Macbeth color chart for example... and then folks could define their own (monitor specific) color profile which would then (near) perfectly match?

For those interested, you'll find some tools here (requires Java) - http://www.brucelindbloom.com/index.html

[Chuft-Captain]

I think the real problem is, none of the current versions of Celestia have adjustable gamma/color matching. One solution might be to add a gamma slider, but I'm not sure how simple that'd be for Windows and Linux.

However the fact remains it doesn't really solve the general issue of lack of color matching support in Celestia. As an interim measure, I'd recommend using any of the widely available free monitor gamma adjustment utilities.

This is something I have been worried about for a while, and I must admit that it's an area of expertise in which I'm a little "green'.

As I create my addons on a specific monitor (with brightness, contrast, color balance, etc set to my own personal preferences) they won't nescessarily have the appearance that I intended, on other people's setups. (For example, I notice a big difference between my main display and the laptop screen in terms of brightness, contrast and color saturation)
Also... 80% brightness, 70% contrast settings on my monitor is not nescessarly the same as 80% brightness, 70% contrast on a differently rated monitor from another manufacturer (or even the same manufacturer ).

The question I have is: what should be considered the "reference setup".... and how to calibrate it?

Suggestions???

[Vincent]

I think the real problem is, none of the current versions of Celestia have adjustable gamma/color matching. One solution might be to add a gamma slider, but I'm not sure how simple that'd be for Windows and Linux.

A "palette setting" feature including a gamma correction slider (for line and label colors) could be easily added to the Lua Tools. Of course, one advantage of doing this via Lua is that it would be cross-platform.
This would require adding the celestia:getlinecolor and celestia:getlabelcolor methods to celx scripting. Not a big deal...

[dirkpitt]

That's a start, I'm all for the cross platform script-based approach. But will your gamma slider apply gamma adjustment for the entire Celestia rendered scene (including planets, models)? Will the slider require the use of lua hooks?

[selden]

ElChristou,

One should use formal methods of setting the colors of a screen to be correct. These techniques have been documented and available in the "hi-fi" video market for many years. The resulting colors aren't as vivid as many people prefer, but they can be as nearly accurate as the built-in RGB colors of the display can show.

One simplified procedure is described on the Web page http://blog.audiovideointeriors.com/307howto/

Some commercial products to do this are listed on the Web page http://www.ramelectronics.net/html/Vide ... ation.html

I'm not at all recommending that you buy anything from this particular vendor. Their Web page just happened to be near the top when I searched for the products that I've used: "Avia" and "Video Essentials".

[ElChristou]

I'm not really hot for a gamma slider because again the setting will be done by the user and so cannot be thrust in the meaning that both devs or an addon authors cannot be sure of the result the final user will see...

[Vincent]

That's a start, I'm all for the cross platform script-based approach. But will your gamma slider apply gamma adjustment for the entire Celestia rendered scene (including planets, models)?

Da Woon,

No, I've edited my post while you were writing yours: the Lua gamma correction slider would only apply changes to lines and labels colors. Does the entire rendered scene really need gamma correction setting? If yes, then the gamma slider should indeed be implemented in the C++ code, as you suggested.

Will the slider require the use of lua hooks?

The slider will use the lua hooks that are already implemented in the code. No need to add more hooks. Is that what you were asking ?

[ElChristou]

ElChristou,

One should use formal methods of setting the colors of a screen to be correct. These techniques have been documented and available in the "hi-fi" video market for many years. The resulting colors aren't as vivid as many people prefer, but they can be as nearly accurate as the built-in RGB colors of the display can show...

No only in video market, but from the beginning of digital printing! Ok, the specter is not the same (CMYK instead of RGB) but all elements of the printing chain must be finally calibrated.

In our case I think it's unrealistic to think that people will be able to calibrate correctly their monitor it's why at least it would be nice if Celestia could control and correct if possible the color profile used by a config.

Now yes, the dev team and active members should try to calibrate their monitor the best they can using the same protocol (we could try to define it if there is a real interest)

[Fenerit]

Thanks Vincent in advance for this implementation!

[ElChristou]

Now what do you look at? what is more important? the line that will help you or the object that you are searching?

Both ! The stars and the grid don't compete, they are complementary. When we need both at the same time, both must be clearly visible. Especially on the wall, in front of a large audience. And also on a simple PC screen. I'm not asking to have a vivid grid, but a visible one nonetheless. It's a matter of compromise.

And there happens some cases where the grid itself may become more important than the objects ! (when we have to explain what are the conventions used for the celestial coordinates, or to show all the various coordinates systems, for example).

The purpose of constellations is to help in finding stars, no?

Not necessarily. The constellations may be seen as "objects" in their own right, with some historical signification (mythology, religion, etc). Sometimes, the chart itself (grid, constellation lines, borders) may be more interesting than the objects (stars) it's supposed to map.

The constellations borders are very much alike the countries borders on a terrestrial globe : In some topics, they may be more important that the countries details enclosed inside the borders.

EDIT : This reminds me a feature that could be fun, for the celestial grid itself : When you press the ";" key, the grid appears smoothly with some fade-in effect. When you turn it OFF, it goes away with a smooth fade-out effect, like in Stellarium.

Cham, to me you have here some arguments already turned to a very specific use: education.
All the examples you takes are very specific so I suppose they should use specific palettes... (that you can now load easily depending of what you have to show)
I think that the basic palette should be a generalist one made for pure observation of objects and done for computer screen. We should avoid the old argument of the projector because again it's a specific issue that can be fix with a specific palette depending on one use.
(Now I do agree that all must be visible of course!)

The king of fading you are mentioning has been used recently by Vincent for his Lua Tools and is very nice. Indeed perhaps all elements could use such a fading in/out...

[Vincent]

Guys,

I can see at least 4 different discussions in this thread:
1) setting the label and line colors palette (main subject)
2) adding a gamma correction slider
3) running a celx script to perform initial settings, and then launching a start.cel script
4) adding a fading effect to the grid

I've started new topics for 2) and 3) in order to keep this thread focused on the main subject 1). What about doing the same with 4) ?

[dirkpitt]

Does the entire rendered scene really need gamma correction setting?

See my reply in the other thread.
Basically, I think a slider just for lines and colors is probably enough for now.

Will the slider require the use of lua hooks?

The slider will use the lua hooks that are already implemented in the code. No need to add more hooks. Is that what you were asking ?

Yup, sounds cool.

[Cham]

Cham, to me you have here some arguments already turned to a very specific use: education.
All the examples you takes are very specific so I suppose they should use specific palettes... (that you can now load easily depending of what you have to show)
I think that the basic palette should be a generalist one made for pure observation of objects and done for computer screen. We should avoid the old argument of the projector because again it's a specific issue that can be fix with a specific palette depending on one use.
(Now I do agree that all must be visible of course!).

ElChristou,

education is one of the MAIN applications of Celestia. It is used all around the world in schools and planetariums. Even NASA is using it for presentations to the public. So what I was talking about is certainly NOT a very specific and "specialized" application of the software. And the wall screen is a very important argument too, since it's used all around the world in planetariums and schools. Even ESA was showing Celestia to us (here, recently on the forum), on the large screens on the walls of its control room, which isn't exactly a simple computer screen.

So the default color palette MUST have some strong enough colors, to be adequate on ALL systems. Currently, the colors used for the constellations, grids, and many labels are CLEARLY INADEQUATE for MANY users.

If some home users like you want some smoother tones, it is HIS responsability to use a CELX script to change the colors.

[ElChristou]

ElChristou,

education is one of the MAIN applications of Celestia. It is used all around the world in schools and planetariums. Even NASA is using it for presentations to the public. So what I was talking about is certainly NOT a very specific and "specialized" application of the software. And the wall screen is a very important argument too, since it's used all around the world in planetariums and schools. Even ESA was showing Celestia to us (here, recently on the forum), on the large screens on the walls of its control room, which isn't exactly a simple computer screen.

Well as far as I recall Celestia philosophy is to present a general framework to the public for any kind of use...
Are you saying I miss something and now Celestia should be officially considered as an educational tool before all?
Is there consensus at dev level? if yes, then no problemo with your above statement of course...

...Currently, the colors used for the constellations, grids, and many labels are CLEARLY INADEQUATE for MANY users.

That we already knows, it's why meanwhile we don't have a control on color profile the palette should be reset to old values or any other flashy palette.
Chris, will you do that soon to not have to repeat this again and again?

[chris]

ElChristou,

education is one of the MAIN applications of Celestia. It is used all around the world in schools and planetariums. Even NASA is using it for presentations to the public. So what I was talking about is certainly NOT a very specific and "specialized" application of the software. And the wall screen is a very important argument too, since it's used all around the world in planetariums and schools. Even ESA was showing Celestia to us (here, recently on the forum), on the large screens on the walls of its control room, which isn't exactly a simple computer screen.

Well as far as I recall Celestia philosophy is to present a general framework to the public for any kind of use...
Are you saying I miss something and now Celestia should be officially considered as an educational tool before all?
Is there consensus at dev level? if yes, then no problemo with your above statement of course...

...Currently, the colors used for the constellations, grids, and many labels are CLEARLY INADEQUATE for MANY users.

That we already knows, it's why meanwhile we don't have a control on color profile the palette should be reset to old values or any other flashy palette.
Chris, will you do that soon to not have to repeat this again and again?

I'd rather not just revert to the old palette, since I feel that the new one has many advantages. Surely we can just increase the brightness of the elements that currently appear too dim. Let's get a palette that makes all thhe elements visible on everyone's system, and then if people want to tweak the colors for aesthetic reasons via a script, they can do so.

--Chris

[ElChristou]

...I'd rather not just revert to the old palette, since I feel that the new one has many advantages. Surely we can just increase the brightness of the elements that currently appear too dim. Let's get a palette that makes all thhe elements visible on everyone's system, and then if people want to tweak the colors for aesthetic reasons via a script, they can do so...

As you wish, but I prefer someone else do the change to not have anymore Cham on my back!

[Vincent]

I'd rather not just revert to the old palette, since I feel that the new one has many advantages. Surely we can just increase the brightness of the elements that currently appear too dim. Let's get a palette that makes all thhe elements visible on everyone's system, and then if people want to tweak the colors for aesthetic reasons via a script, they can do so.

I agree with Chris. I find both Christophe's and Martin's new palettes far better than the old one. They may just need some extra tuning, and voil?  !

As you wish, but I prefer someone else do the change to not have anymore Cham on my back!

Hey, you both really are like and ...

[ElChristou]

Hey, you both really are like and ...

DO you mean my avatar make you think in a dog??

Indeed, I was just kidding, despite his "caract??re de cochon" I still appreciate Cham!

[Vincent]

DO you mean my avatar make you think in a dog??

No, this was just for kidding. I do like your avatar. Far better than this one: